In the rainforests of the Guineo-Congolian region, several native tree species have been tested in plantations established with different silvicultural methods and objectives. The results of these experiments remained scattered, hampering our ability to identify the key drivers of variability in survival and growth of planted species. In this study, we carried out a systematic review of the literature. From 45 selected studies, a database was compiled of 89 native tree species planted in different forest types (evergreen, semideciduous and transition). The data included plantation age, survival, height and diameter growth. For each species, information was collected on the planting method (understorey, line planting, gap, degraded area, regrowth and clear-cut), and species functional traits (species guild, dispersal mode, wood density and leaf phenology). Tree survival, height and diameter growth were modelled using linear mixed-effect models. Tree survival depended mainly on plantation age, and mortality was the highest in the seven first years. However, survival did not significantly depend on planting method or species traits. In the study plantations, height and diameter growth depended on planting method and species guild. Diameter growth was negatively correlated with wood density. Pioneer, non-pioneer light-demanding and shade-tolerant species grew faster in diameter when planted in degraded areas and clear-cuts. Pioneer species grew the fastest in gaps. Although we did not find an effect of forest type on tree survival and growth, the variability between sites was substantial. This study provides empirical evidence that planting methods need to be adapted to the species guild.

Pinus koraiensis (Sieb. et Zucc.) is a coniferous tree species naturally distributed in northeastern China. However, the effects of gene flow on its genetic diversity and structure remain unclear. This study investigates these dynamics in seven populations using ten microsatellite markers. The results show a high level of genetic diversity within the populations (Ho = 0.633, He = 0.746). In addition, molecular analysis of variance (AMOVA) shows that 98% of genetic diversity occurs within populations, with minimal differentiation between populations (Fst = 0.009–0.033). Gene flow analysis shows significant migration rates between specific population pairs, particularly C-TH (87%), LS-Y (69%) and TH-LS (69%), suggesting genetic homogenization. Bayesian clustering (STRUCTURE) supports admixture and weak population differentiation. Environmental factors, especially temperature-related variables, significantly influence genetic patterns. Partial Mantel tests and multiple matrix regression show strong correlations between genetic distance and adaptations to cold temperatures (bio6 and bio11). Overall, this study emphasizes the robust genetic diversification and high migration rates in the populations of P. koraiensis and highlights their resilience. These results emphasize the importance of incorporating genetic and ecological factors into conservation strategies for sustainable forest management. This research provides valuable insights into the complex interplay of genetic variation, gene flow and environmental influences in forest tree species and improves our understanding of their adaptive mechanisms.

Photodegradation is considered as a universal contributing factor to litter decomposition and carbon (C) cycling within the Earth’s biomes. Identifying how solar radiation modifies the molecular structure of litter is essential to understand the mechanism controlling its decomposition and reaction to shifts in climatic conditions and land-use. In this study, we performed a spectral-attenuation experiment following litter decomposition in an understory and gap of a temperate deciduous forest. We found that short-wavelength visible light, especially blue light, was the main factor driving variation in litter molecular structure of Fagus crenata Blume, Quercus crispula Blume, Acer carpinifolium Siebold & Zuccarini and Betula platyphylla Sukaczev, explaining respectively 56.5%, 19.4%, 66.3%, and 16.7% of variation in its chemical composition. However, the variation also depended on canopy openness: Only in the forest gap was lignin aromatic C negatively associated with C-oxygen (C–O) bonding in polysaccharides receiving treatments containing blue light of the full spectrum of solar radiation. Regardless of species, the decomposition index of litter that explained changes in mass and lignin loss was driven by the relative content of C–O stretching in polysaccharides and lignin aromatic C. The results suggest that the availability of readily degradable polysaccharides produced by the reduction in lignin aromatic C most plausibly explains the rate of litter photodegradation. Photo-products of photodegradation might augment the C pool destabilized by the input of readily degradable organic compounds (i.e., polysaccharides).

Leptocybe invasa is an invasive pest, native to Australia, which causes serious damage to Eucalyptus all over the world. Here, we monitored gall development in resistant and susceptible Eucalyptus clones to determine whether plant genotype affects the durations of the different gall stages. Gall development varied among six Eucalyptus clones that differed in susceptibility to L. invasa viz., PE-5, 316, 3011, PE-11, 3020 and P-13 in Punjab in a nethouse. In susceptible clones PE-5 and 316, L. invasa emerged from both green and pink galls. Five stages of gall formation were found: Stage 1 (tissue disruption), Stage 2 (gall development), Stage 3 (glossy pink), Stage 4 (dull pink) and Stage 5 (exit hole) in susceptible clones when adults emerged from pink galls. However, in resistant clones, adults emerged only from green galls, and galls formed in three stages. In the susceptible clones, when adults emerged from pink galls, the life cycle was 105–115 d; however, when adults emerged from green galls, the duration was significantly shorter (81–87 d). In the most-resistant clone, P-13, corky tissue formed after oviposition, and galls did not develop further. In the resistant clones (3020, PE-11 and 3011), adults emerged from green galls, and the life cycle lasted 90–96 d. When adults emerged from green galls in susceptible and resistant clones, Stage 1 lasted longer in resistant clones than in the susceptible; however, in susceptible clones, Stage 5 was longer. When adults emerged from pink galls in susceptible clones and from green galls in resistant clones, the life cycle was longer in susceptible clones. In susceptible clones, the number of emergence holes was significantly higher than resistant clones. Gall width and gall length also differed significantly between susceptible and resistant clones. The results showed that the Eucalyptus genotype had a significant effect on gall development induced by gall wasps.

Biological invasions, driven mainly by human activities, pose significant threats to global ecosystems and economies, with fungi and fungal-like oomycetes playing a pivotal role. Ink disease, caused by Phytophthora cinnamomi and P. ×  cambivora, is a growing concern for sweet chestnut stands (Castanea sativa) in Europe. Since both pathogens are thermophilic organisms, ongoing climate change will likely exacerbate their impact. In this study, we applied species distribution modeling techniques to identify potential substitutive species for sweet chestnut in the light of future climate scenarios SSP126 and SSP370 in southern Switzerland. Using the presence-only machine learning algorithm MaxEnt and leveraging occurrence data from the global dataset GBIF, we delineated the current and projected (2070–2100) distribution of 28 tree species. Several exotic species emerged as valuable alternatives to sweet chestnut, although careful consideration of all potential ecological consequences is required. We also identified several native tree species as promising substitutes, offering ecological benefits and potential adaptability to climatic conditions. Since species diversification fosters forest resilience, we also determined communities of alternative species that can be grown together. Our findings represent a valuable decision tool for forest managers confronted with the challenges posed by ink disease and climate change. Given that, even in absence of disease, sweet chestnut is not a future-proof tree species in the study region, the identified species could offer a pathway toward resilient and sustainable forests within the entire chestnut belt.

Rhododendron micranthum Turcz. is a shrub esteemed for its ornamental and medicinal attributes within the Changbai Mountain range of China. We selected 3-year saplings and subjected them to four distinct light conditions: full light (CK), 70% light (L1), 50% light (L2), and 30% light (L3) to investigate variations in morphology, photosynthetic responses, stomatal ultrastructure as well as the mechanisms through which these saplings adapt to differing lighting environments. The results indicate that L2 leaves exhibit significantly greater length, width, and petiole development compared to other treatments across varying intensities. Over time, chlorophyll content and PSII levels in L2-treated saplings surpass those observed in other treatments; Proline (PRO), malondialdehyde (MDA), and soluble protein (SP) contents are markedly lower under L2 treatment. Catalase (CAT) and superoxide dismutase (SOD) demonstrate significant correlations across various light conditions but respond differently among treatments, indicating distinct species sensitivities to light intensity while both contribute to environmental stress resistance mechanisms. Findings reveal that R. micranthum saplings at 50% light intensity benefit from enhanced protection via antioxidant enzymes, and shading reduces osmotic adjustment substances yet increases chlorophyll content. Stomatal length/width along with conductance rates and net photosynthesis rates for L2 exceed those of CK, suggesting an improved photosynthetic structure conducive to efficient photosynthesis under this condition. Thus, moderate shading represents optimal growth at 50% illumination, a critical factor promoting sapling development. This research elucidates the ideal environment for R. micranthum adaptation to varying light conditions supporting future conservation initiatives.

Human activities contribute to elevated nitrogen input in terrestrial ecosystems, influencing the composition of soil nutrients and microbial diversity in forest ecosystems. In this study, we built four addition treatments (0, 20, 40, and 80 kg ha⁻¹ a⁻¹ N for 6 a) at a Korean pine plantation of different soil horizons (organic (O) horizon, ranging from 0 to 10 cm, and organomineral (A) horizon, extending from 10 to 20 cm) to evaluate responses of the structure of saprophytic fungal communities. Here, 80 kg ha⁻¹ a⁻¹ N treatment significantly decreased the community richness in soil A horizon with the Chao1 index decreasing by 12.68%. Nitrogen addition induced changes in the composition of saprophytic fungi community between the different soil horizons. The co-occurrence network and its associated topological structure were utilized to identify mycoindicators for specific fungi to both soil horizons and nitrogen addition levels. In soil O horizon, the mycoindicators included Penicillium, Trichoderma, Aspergillus, and Pseudeurotium across control, low, medium, and high nitrogen treatments. In soil A horizon, Geomyces, Cladophialophora, Penicillium, and Pseudeurotium were identified as mycoindicators. Structural equation modeling determined NH₄⁺-N as the key factor driving changes in saprotrophic fungal communities. Our study aimed to screen mycoindicators that can respond to the increasing global nitrogen deposition and to assess the roles of these mycoindicators in the saprophytic fungal community structure within Korean pine plantations in northeast China.

Tree trunk instance segmentation is crucial for under-canopy unmanned aerial vehicles (UAVs) to autonomously extract standing tree stem attributes. Using cameras as sensors makes these UAVs compact and lightweight, facilitating safe and flexible navigation in dense forests. However, their limited onboard computational power makes real-time, image-based tree trunk segmentation challenging, emphasizing the urgent need for lightweight and efficient segmentation models. In this study, we present RT-Trunk, a model specifically designed for real-time tree trunk instance segmentation in complex forest environments. To ensure real-time performance, we selected SparseInst as the base framework. We incorporated ConvNeXt-T as the backbone to enhance feature extraction for tree trunks, thereby improving segmentation accuracy. We further integrate the lightweight convolutional block attention module (CBAM), enabling the model to focus on tree trunk features while suppressing irrelevant information, which leads to additional gains in segmentation accuracy. To enable RT-Trunk to operate effectively under diverse complex forest environments, we constructed a comprehensive dataset for training and testing by combining self-collected data with multiple public datasets covering different locations, seasons, weather conditions, tree species, and levels of forest clutter. Compared with the other tree trunk segmentation methods, the RT-Trunk method achieved an average precision of 91.4% and the fastest inference speed of 32.9 frames per second. Overall, the proposed RT-Trunk provides superior trunk segmentation performance that balances speed and accuracy, making it a promising solution for supporting under-canopy UAVs in the autonomous extraction of standing tree stem attributes. The code for this work is available at https://github.com/NEFU-CVRG/RT-Trunk.

To better understand the effects of ground-level ozone (O₃) on nutrients and stoichiometry in different plant organs, urban tree species Celtis sinensis, Cyclocarya paliurus, Quercus acutissima, and Quercus nuttallii were subjected to a constant exposure to charcoal-filtered air (CF), nonfiltered air (NF), or NF + 40, 60, or 80 nmol O₃ mol^–1 (NF40, NF60, and NF80) starting early in the summer of the growing season. At the end of summer, net CO₂ assimilation rate (A), stomatal conductance (g_s), leaf mass per area (LMA), and/or leaf greenness (SPAD) either were not significantly affected by elevated O₃ or were even higher in some cases during the summer compared with the CF or NF controls. LMA was significantly lower in autumn only after the highest O₃ exposures. Compared to NF, NF40 caused a large increase in g_s across species in late summer and more K and Mn in stems. At the end of the growing season, nutrient status and stoichiometric ratios in different organs were variously altered under O₃ stress; many changes were large and often species-specific. Across O₃ treatments, LMA was primarily associated with C and Mg levels in leaves and Ca levels in leaves and stems. NF40 enriched K, P, Fe, and Mn in stems, relative to NF, and NF60 enhanced Ca in leaves relative to CF and NF40. Moreover, NF resulted in a higher Ca/Mg ratio in leaves of Q. acutissima only, relative to the other O₃ regimes. Interestingly, across species, O₃ stress led to different nutrient modifications in different organs (stems + branches vs leaves). Thus, ambient and/or elevated O₃ exposures can alter the dynamics and distribution of nutrients and disrupt stoichiometry in different organs in a species-specific manner. Changes in stoichiometry reflect an important defense mechanism in plants under O₃, and O₃ pollution adds more risk to ecological stoichiometries in urban areas.

The increasing frequency of extreme weather events raises the likelihood of forest wildfires. Therefore, establishing an effective fire prediction model is vital for protecting human life and property, and the environment. This study aims to build a prediction model to understand the spatial characteristics and piecewise effects of forest fire drivers. Using monthly grid data from 2006 to 2020, a modeling study analyzed fire occurrences during the September to April fire season in Fujian Province, China. We compared the fitting performance of the logistic regression model (LRM), the generalized additive logistic model (GALM), and the spatial generalized additive logistic model (SGALM). The results indicate that SGALMs had the best fitting results and the highest prediction accuracy. Meteorological factors significantly impacted forest fires in Fujian Province. Areas with high fire incidence were mainly concentrated in the northwest and southeast. SGALMs improved the fitting effect of fire prediction models by considering spatial effects and the flexible fitting ability of nonlinear interpretation. This model provides piecewise interpretations of forest wildfire occurrences, which can be valuable for relevant departments and will assist forest managers in refining prevention measures based on temporal and spatial differences.

The study determined the carbon stocks and litter nutrient concentration in tropical forests along the ecological gradient in Kenya. This could help understand the potential of mitigating climate change using tropical forest ecosystems in different ecological zones, which are being affected by climate change to a level that they are becoming carbon sources instead of sinks. Stratified sampling technique was used to categorize tropical forests into rain, moist deciduous and dry zone forests depending on the average annual rainfall received. Simple random sampling technique was used to select three tropical forests in each category. Modified consistent sampling technique was used to develop 10 main 20 m × 100 m plots in each forest, with 20 2 m × 50 m sub-plots in each plot. Systematic random sampling technique was used in selecting 10 sub-plots from each main plot for inventory study. Non-destructive approach based on allometric equations using trees’ diameter at breast height (DBH), total height and species’ wood specific gravity were used in estimating tree carbon stock in each forest. Soil organic carbon (SOC) and litter nutrient concentration (total phosphorus and nitrogen) were determined in each forest based on standard laboratory procedures. The results indicated that, whilst trees in rain forests recorded a significantly higher (p < 0.001) DBH (20.36 cm) and total tree height (12.1 m), trees in dry zone forests recorded a significantly higher (p < 0.001) specific gravity (0.67 kg m⁻³). Dry zone tropical forests stored a significantly lower amount of total tree carbon of 73 Mg ha⁻¹, compared to tropical rain forests (439.5 Mg ha⁻¹) and moist deciduous tropical forests (449 Mg ha⁻¹). The SOC content was significantly higher in tropical rainforests (3.9%), compared to soils from moist deciduous (2.9%) and dry zone forests (1.8%). While litter from tropical rain forests recorded a significantly higher amount of total nitrogen (3.4%), litter from dry zone forests recorded a significantly higher concentration of total phosphorus (0.27%). In conclusion, ecological gradient that is dictated by the prevailing temperatures and precipitation affects the tropical forests carbon stock potential and litter nutrient concentration. This implies that, the changing climate is having a serious implication on the ecosystem services such as carbon stock and nutrients cycling in tropical forests.

Understanding how environmental adaptation varies among families within a species is critical to adapt forestry activities such as management and breeding to possible future climate change. The present study examined home-site advantage and local advantage in growth and basic density of wood in 36 families of Chamaecyparis obtuse (Siebold et Zucc.) Endl., reciprocally planted at two progeny test sites with differing climatic conditions in Japan. A significant home-site advantage for growth was detected between the lowland and mountainous regions within the Kanto breeding region. In addition, the effects of climate differentials between the selection site of mating parents and the progeny test site on growth and basic density were investigated. As a result, temperature was identified as the most significant climatic factor attributed to local adaptation for growth traits. Elongation and radial growth were adversely influenced when the progeny test site temperature exceeded the provenance temperature by more than 2 °C. Therefore, it is crucial to account for temperature differences between the provenance and the planting site to adapt afforestation and forest tree breeding to climate change in the future.

Individual tree health plays a vital role in maintaining a forest’s ecological functions, including resources for waterfowl and other wildlife. Seasonal flooding due to altered hydrology is a major stressor on individual tree health in Greentree reservoirs (GTR), impounded bottomland hardwood forests especially less water tolerant species like red oaks (Quercus spp.). We evaluated the health of individual red oak species (n = 6,432) in 662 plots across elevation gradients in 12 GTRs within the lower Mississippi Alluvial Valley using two tree health assessment approaches. The first approach assigns tree conditions (i.e., stressed, moderate, low) based on overall qualitative tree attributes, while the second approach ranks stress, assigning numerical value based on the severity of four distinct qualitative tree attributes (i.e., tip dieback, epicormics branch, bark condition, basal swell). The result indicated that the highest mean stress rank and the highest proportion of stressed tree conditions were red oak species, nuttall oak (Q. texana; 18.59, 0.44), willow oak (Q. phellos; 18.66, 0.38) and cherrybark oak (Q. pagoda; 18.90, 0.37). Red oak stress is positively correlated to elevation across the landscape (τ = 0.10, p < 0.001), but is negatively correlated to relative elevation, topographical changes, within each GTR (τ =  − 0.11, p < 0.001). Additionally, the two health assessments are significantly associated (χ² = 313.78, df = 2, p < 0.001) and had a 13.1% misclassification rate. By utilizing the stress rank method for better classification of tree conditions to understand the adverse effect of prolonged flooding on the health of desirable red oak and other native tree species, management practices can be adjusted to improve tree health in GTRs, benefiting both wildlife and economic value.

Climate change is expected to alter the population dynamics of pioneer tree species and their planned use in sustainable forest management, but we have a limited understanding of how their demographic rates change in response to climate changes during ecological restoration. Based on 12 years of demographic data for a pioneer tree species (Pinus massoniana) censused in three plots that correspond to three stages of ecological restoration in southeastern China. We built integral projection models (IPMs) to assess vital rates (survival, growth, reproduction) and population growth in each plot, then evaluated demographic changes to simulated changes in seasonal mean temperature and precipitation in the current and previous census period. The plot representing the medium restoration stage had the highest population growth rate (λ = 0.983). Mean population survival probability increased with ecological restoration, and reproduction probability was significantly suppressed at the high restoration stage. Survival is always the most important vital rate for λ, and climate affects λ primarily via survival at each restoration stage. The current spring temperature was the most critical climate variable for λ in the low and medium restoration stages, and previous summer temperature was most critical in the high restoration stage. Simulated warming leads to a decrease in the stochastic population growth rate (λ_s) of P. massoniana in every stage. These findings suggest that during ecological restoration, P. massoniana responds to habitat change via modified demographic performance, thus altering its response to climate change. Despite diverse responses to climate change, the persistence of P. massoniana populations is facing a widespread threat of warming states at each restoration stages.

The increasing frequency and intensity of forest fires, driven by climate change and human activities, pose a significant threat to vital forest ecosystems, particularly where fire is not a natural element in the regeneration cycle. This study aims to identify the indicators influencing forest fire vulnerability and compare maps of forest fire susceptibility that are based on the Intergovernmental Panel on Climate Change tripartite model, with a focus on the vulnerable Hyrcanian forest region in Golestan Province, northern Iran, where forest fires have caused considerable economic losses. On the basis of expert opinions and a literature review, we used geographic information systems, remote sensing and machine learning techniques to select and weigh 30 biophysical, environmental and socioeconomic indicators that affect forest fire vulnerability in the study area. These indicators were rigorously normalized, weighted and amalgamated into a comprehensive forest fire vulnerability index to analyze forest exposure, sensitivity and adaptive capacity. We thus identified and mapped areas with very high forest fire exposure, high sensitivity and low adaptive capacity for urgent targeted intervention and strategic planning to mitigate the impacts of forest fires. The results also revealed a set of critical indicators that contribute more significantly to forest fire vulnerability (e.g., precipitation, elevation and factors related to biodiversity, human activity and economic reliance on forest resources). Our results provide insights that can inform policy-making, community engagement and environmental management strategies to mitigate the vulnerabilities associated with forest fires in the Hyrcanian forest.

Models that predict a forest stand’s evolution are essential for developing plans for sustainable management. A simple mathematical framework was developed that considers the individual tree and stand basal area under random resource competition and is based on two assumptions: (1) a sigmoid-type stochastic process governs tree and stand basal area dynamics of living and dying trees, and (2) the total area that a tree may potentially occupy determines the number of trees per hectare. The most effective method to satisfy these requirements is formalizing each tree diameter and potentially occupied area using Gompertz-type stochastic differential equations governed by fixed and mixed-effect parameters. Data from permanent experimental plots from long-term Lithuania experiments were used to construct the tree and stand basal area models. The new models were relatively unbiased for live trees of all species, including silver birch (Betula pendula Roth) and downy birch (Betula pubescens Ehrh.), [spruce (Picea abies), and pine (Pinus sylvestris)]. Less reliable predictions were made for the basal area of dying trees. Pines gave the highest accuracy prediction of mean basal area among all live trees. The mean basal area prediction for all dying trees was lower than that for live trees. Among all species, pine also had the best average basal area prediction accuracy for live trees. Newly developed basal area growth and yield models can be recommended despite their complex formulation and implementation challenges, particularly in situations when data is scarce. This is because the newly observed plot provides sufficient information to calibrate random effects.

The article considers the impact of forestry machines on the soil of the cutting areas and presents the results of the impact of harvesters of different classes (middle-small, middle and heavy) and configurations of wheeled equipment and additional equipment on the soil of the cutting areas in the conditions of Kronoberg County (South of Sweden). Methods to reduce negative impact of wheeled harvesters on the soil of forests are proposed. The aim of the research is to assess the effect of the structural parameters of the wheel harvesters of different class on the soil of the cutting areas. Wheeled harvesters were loaded with 60 kN force. The results of experimental studies of the impact of wheeled harvesters on the forest soil are presented. Recommendations on the possibility of testing the results of research in the conditions of the rental base of the Western part of the North-Western Federal District of the Russian Federation are given.

The acclimation capacity of Betula pendula and Betula pubescens was studied over 4 years in common gardens in central Italy (43° N) and southern (61° N) and northern Finland (67° N), representing drastically different photoperiod and climate in temperate, boreal and subarctic vegetation zones. Two study sites that differed in soil fertility were established at each location, giving a total of six common gardens. The birch material was micropropagated from naturally regenerated stands of B. pendula and B. pubescens from Susa Valley and Rochemolle Valley in northern Italy, Punkaharju in southern Finland and Kittilä in northern Finland. The plants were measured for height growth, stem diameter, leaf chlorophyll content, leaf herbivory and pathogen damage. The effects of soil fertility on the common garden results were also analyzed. The results showed high acclimation capacity of B. pendula and B. pubescens after a long-range transfer from southern to northern Europe, despite the major shift in climate and photoperiod. First-year growth on average was best in boreal southern Finland for all origins. Betula pendula grew more than B. pubescens in Italy and southern Finland, while B. pubescens grew more in northern Finland and better tolerated the northward transfer. The height growth of origins showed a clear latitude gradient from slowly growing northern to fast growing southern origins in the nursery and laboratory, but not in the field. Soil fertility explained a significant part of variation among locations not only for growth variables, but also for leaf chlorophyll content and leaf herbivory and pathogen damage. Leaf herbivore and pathogen damage was greatest in southern Finland. Our results demonstrate good survival of birch from northern Italy in Finnish conditions and support the possibility of long-range south-to-north transfer of Betula species to provide resistant planting material in boreal forests for the rapidly changing climate.

Enhancing the carbon sink of terrestrial ecosystems is an essential nature-based solution to mitigate global warming and achieve the target of carbon neutrality. Over recent decades, China has launched a series of long-running and large-scale ambitious forestation projects. However, there is still a lack of year-to-year evaluation on the effects of afforestation on carbon sequestration. Satellite remote sensing provides continuous observations of vegetation dynamics and land use and land cover change, is becoming a practical tool to evaluate the changes of vegetation productivity driven by afforestation. Here, a spatially-explicit analysis was conducted by combining Moderate Resolution Imaging Spectroradiometer (MODIS) land cover and three up-to-date remote sensing gross primary productivity (GPP) datasets of China. The results showed that the generated afforestation maps have similar spatial distribution with the national forest inventory data at the provincial level. The accumulative areas of afforestation were 3.02 × 10⁵ km² in China from 2002 to 2018, it was mainly distributed in Southwest (SW), South (Sou), Southeast (SE) and Northeast (NE) of China. Among them, SW possesses the largest afforestation sub-region, with an area of 9.38 × 10⁴ km², accounting for 31.06% of the total. There were divergent trends of afforestation area among different sub-regions. The southern sub-regions showed increasing trends, while the northern sub-regions showed decreasing trends. In keeping with these, the center of annual afforestation moved to the south after 2009. The southern sub-regions were the majority of the cumulative GPP, accounting for nearly 70% of the total. The GPP of new afforestation showed an increasing trend from 2002 to 2018, and the increasing rate was higher than existing forests. After afforestation, the GPP change of afforestation was higher than adjacent non-forest over the same period. Our work provides new evidence that afforestation of China has enhanced the carbon assimilation and will deepen our understanding of dynamics of carbon sequestration driven by afforestation.

Primary challenges with a forest inventory program are surveyors with various levels of experience and the turnover of inexperienced surveyors. Few studies have looked at the consistency of an instrument’s results among inexperienced surveyors. Most studies have assessed whether instruments were significantly different. These tests do not indicate whether instruments were statistically equivalent, i.e., that choosing either one would be acceptable under a certain level of tolerance. This study evaluated the consistency and statistical equivalence among instruments for measuring diameter at breast height (DBH) and for total tree height (HT) among inexperienced surveyors. The study was conducted as a randomized experiment with students from an introductory tree measurement course, using four types of DBH and HT instruments, and with different tree attributes. For DBH, the results show that D-tape was the most consistent across tree attributes and teams of inexperienced surveyors and was only statistically interchangeable with Caliper with a tolerance ≥ 3 cm. For HT, Ultrasound was the most consistent but only statistically interchangeable with Laser with a tolerance ≥ 8 m. A single type of instrument for measuring DBH and for HT is recommended, especially when field crews may be a mixture of experienced and inexperienced surveyors. Our study provides initial recommendations on the choice of instruments when either purchasing new ones or replacing old ones in forest inventories.

Entomopathogenic nematodes (EPNs) represent a promising biological control strategy for managing insect pest populations, offering an environmentally sustainable alternative to conventional chemical pesticides. This review examines the application of EPNs in forestry, highlighting their biological and ecological characteristics, mechanisms of action, and efficacy against key forest pests. By exploring various methods of EPN application, including soil injection, foliar spray, and trunk injection, practical challenges and potential solutions for effective implementation are assessed. Case studies demonstrate successful use of EPNs in controlling pests such as bark beetles, wood borers, and root weevils, underscoring their potential for integration into integrated pest management (IPM) programs. Despite current limitations, including environmental sensitivity and application constraints, ongoing research and technological advancements continue to enhance the efficacy and reliability of EPNs. This review underscores the importance of EPNs in sustainable forestry practices and calls for further research to optimize their use and to address existing challenges, ultimately contributing to healthier forest ecosystems and reduced reliance on chemical pesticides.

Volume models for the long-term management of Okomu National Park in Nigeria are not available. The main challenge in assessing forest resources is the lack of accurate, species-specific baseline data and updated information on volume models, growth rates, and disturbances. This complicates the development of effective management plans. This study addresses this by modelling tree volume using temporary sample plots laid out using a systematic line transect method Data was collected from 16 40 m × 50 m plots using a Spiegel relascope. DBH, top, middle, and base diameters, and overall height were measured for trees ≤ 10 cm DBH. Newton’s formula calculated volume of each tree, and per hectare estimates generated. The results showed an average of 132 trees per hectare. Population densities of individual species ranged from 1–11/ha, indicating a low density. Strombosia pustulata was the most abundant species. For coefficients that form the basis for species grouping, species-specific volume equations were developed and grouped into three clusters. Regression equations were fitted and selected based on specific statistical metrics. The volume models showed that generalized

The Andean montane forests provide a wide range of ecosystem services like water supply, carbon sequestration, and biodiversity preservation. Restoration of these forests is critical due to their degraded state and the need to recover, maintain and enhance the ecosystem services they provide. However, we lack understanding of aboveground biomass (AGB) accumulation in restored Andean montane forests. AGB is a key indicator of ecosystem productivity and provides essential data on vegetation carbon stocks, permitting the assess successfulness of restoration efforts. In 2010 the initiative Más Bosques para Medellín was formulated in Medellín City, tropical Andes, Colombia, aiming to restore the forests located in the surrounding rural areas of the city, with interest in preserving the ecosystems services like water supply. The project established 548 ha of mixed plantations with native species. After 13 years, our study aims to developed in situ allometric equations and to evaluate AGB accumulation to assess restoration performance. We measured, harvested, and weighted 144 individuals from these arrangements to fit a general equation for the project and six specific equations for each one of the six most frequent species. The AGB had a positive correlation with diameter at breast height (D), total height (H) and specific wood density (WD). The best general equation uses D and WD as predictors (R² = 0.928). The specific species equations certainly responded to the functional traits of each species. Using the latest inventory of permanent plots of the project we estimated a mean AGB accumulation of 41.91 ± 30.34 Mg ha^–1 and a total accumulation of 22,996.05 Mg of AGB for the 548 ha. We compared these results with studies developed for natural forest in the region and other land covers. We found contrast behaviors in the AGB accumulation across our study zones. The developed equations have broad applicability across the Andes region, offering valuable insights for similar restoration initiatives. Furthermore, will facilitate the assessment of current restoration efforts and inform scientifically based decisions for future mixed plantation practices.

Hydraulic vulnerability, the sensitivity of xylem embolism to water stress, is a major determinant trait associated with conifer mortality. This study investigated branch P50 (50% hydraulic conductivity loss) of adult and juvenile ponderosa pines across multiple locations in the southwestern United States (SWUS), and examined relationships between P50 and climatic conditions, soil properties and forest management. Juvenile ponderosa pines had significantly more negative P50 values than adults on average. Both age groups exhibited a latitudinal pattern in P50 associated with regional climate conditions. Across the SWUS, juvenile P50 was positively correlated with growing season precipitation and temperature, and negatively correlated with soil pH and clay content. In some cases, significant differences in juvenile P50 between SWUS locations were associated with growing season moisture deficit, whereas other significant differences were less attributable to climate and may attest to potential genetic variation between populations. Climate variation, soil properties and population-level acclimation and/or adaptation may all influence the hydraulic vulnerability of juvenile ponderosa pines in the SWUS, promoting differences in stress tolerance of ponderosa pine forests across the region.

Leaf turgor loss point has been recognized as an important plant physiological trait explaining a species’ drought tolerance (π_tlp). Less is known about the variation of π_tlp in time and how seasonal or interannual differences in water availability are affecting π_tlp as a static trait. I monitored the seasonal variation of π_tlp during a drought year starting in early spring with juvenile leaves and assessed the interannual variation in π_tlp of fully matured leaves among years with diverting water availability for three temperate broad-leaved tree species. The largest seasonal changes in π_tlp occurred during leaf unfolding until leaves were fully developed and matured. After leaves matured, no significant changes occurred for the rest of the vegetation period. Interannual variation that could be related to water availability was only present in one of the three tree species. The results suggest that the investigated species have a rapid period of osmotic adjustment early in the growing season followed by a period of relative stability, when π_tlp can be considered as a static trait.

Effective forest regeneration is essential for sustainable forestry practices. In Sweden, mechanical site preparation and manual planting is the dominating method, but sourcing labour for the physically demanding work is difficult. An autonomous scarifying and planting system (Autoplant) could meet the requirements of the forest industry and, for this, a tool for regeneration planning and routing is needed. The tool, Pathfinder, plans the regeneration and routes based on the harvested production (hpr) files, soil moisture and parent material maps, no-go areas (for culture or nature conservation), digital elevation models (DEM), and machine data (e.g., working width, critical slope, time taken for different turn angles). The overall planting solution is either a set of capacity constrained routes or a continuous route and could be used for any planting machine as well as for traditional scarifiers as disc trenchers or mounders pulled by forwarders. Pathfinder was tested on eleven regeneration areas throughout Sweden, both with continuous routes and routes based on a carrying capacity of 1500 seedlings. The net operation area, species and seedling density suggestions were deemed relevant by expert judgement in the field. The routes provided by Pathfinder were compared with solutions given by two experienced drivers and a third solution based on the actual soil scarification at the site. Total driving distance did not differ significantly between the suggestions, but Pathfinder included less side-slope driving on steep slopes (≥ 27% or 15°) and medium slopes (15–27%). The chosen threshold value for steep slopes (where side-slope driving should be avoided) affects the routing, and a lower threshold means more turning and longer driving distance. Pathfinder is not only a tool for routing of planting machines, but also helps in planning of traditional regeneration by providing a more correct net area and tree species suggestions based on the growth of the previous stand. It also diminishes the risk of severe soil disturbance by excluding the wettest area in the planning.

The effectiveness of fluopyram suspension concentrate against pine wilt disease (PWD) is limited by spraying efficiency and water dependence. A traditional dust formulation with strong dispersibility can overcome these shortcomings. However, its efficacy against PWD remains uncertain. This study evaluated the translocation of fluopyram dust within tree tissues, soil and water degradation, and its effective control against PWD. Nursery tests showed effective prevention; field tests showed dust absorption and translocation into pine tissues. Thirty days following application, residual concentrations in soil were low at 0.09 mg kg⁻¹; no detectable residues were found in water samples. Three years after applying fluopyram, its effectiveness increased to approximately 87%. Based on this study, fluopyram had a half-life of 346 d with persistence lasting up to three years. This provides valuable insight for managing PWD through dust applications.

Evapotranspiration (ET), vapor pressure deficit (VPD) and water use efficiency (WUE) are crucial components of the hydrological cycle in forest ecosystems, serving as indicators that reflect the intricate coupling of carbon and water fluxes within the ecosystem. The cold temperate zone, being ecologically fragile and sensitive to climate change, accentuates the significance of exploring the variation characteristics of the dynamics of hydrological processes of a Larix gmelinii forest ET, VPD and WUE were measured in the June to August growing season and the April, May, September and October freeze–thaw period from 2011 to 2016. A structural equation model (SEM) quantitatively analyzed the impact of environmental factors on ecohydrological variables. The results reveal that: (1) Daily average ET in the growing season was significantly higher than in the freeze–thaw period. WUE showed the opposite. Peaks for both ET and VPD occurred in July. In contrast, the freeze–thaw period saw maximum ET and VPD, and minimum WUE in May. July and May emerged as the most active months for hydrological processes in the ecosystem; (2) During the growing season, VPD was influenced by relative humidity (RH) and temperature (T_a), ET responded negatively to solar radiation, and WUE negatively to VPD. Throughout the freeze–thaw period, the ecosystem experienced heat stress, and ecohydrological processes were influenced by T_a. This study provides valuable references for further research on hydrological cycles in forest systems within cold temperate zones.

Studying the reproductive system of the pine wood nematode, Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle, will identify its characteristics and life cycle. This is crucial for developing more targeted control strategies. In this study, the development of the gonads and reproductive organs were observed using microscopy, gonad dissection, and DAPI staining techniques. Second-stage juveniles (J2) had gonads composed of four primordial germ cells (Z1, Z2, Z3, and Z4) that form the adult gonads by proliferation within 72 h at 25 °C. There were subtle differences in somatic gonad cell morphology between males and females, which developed from Z1 and Z4 in third-stage juveniles (J3). These differences became more pronounced at fourth-stage juveniles (J4) and adult stages. Z2 and Z3 germ cells underwent mitosis and two rounds of meiosis, ultimately developing into male and female gametes. Female vulval precursor cells and male cloacal cells developed rapidly during the J4 stage. These results provide a basis for identifying the expression sites and biological functions of key genes regulating reproductive system development. Based on this, in situ hybridization and RNA interference (RNAi) were used to determine the function of the Bxy-glp-1 gene to show that it is involved in vulval formation and spermatogenesis. The results of this study will lay the foundation for disrupting critical stages in the reproduction of B. xylophilus.

As part of the global effort to mitigate climate change effects, New Zealand’s Climate Change Commission has recommended the establishment of 300,000 ha of native trees across the country by 2035. To achieve this goal, significant improvement in seedling production and field establishment is needed. Across New Zealand, there is a trade-off between seedling size and early seedling establishment success; plants grown in large pots are more resistant to weeds, pests and frost; however, they are more expensive and take longer to grow. We tested this trade-off between cost and establishment success by raising seedlings of twelve key native species in three container grade sizes: small, large, and revegetation grade, and tracking their success across five sites around Rotorua, in the Central North Island of New Zealand. After two-year post-planting, we found that high-quality sites and larger container systems tended to promote higher survival and faster early growth (plant height and root collar diameter). Some species, such as Kunzea ericoides and Leptospermum scoparium, survived and grew well (> 75%) even when raised in small container sizes. Other species such as Sophora microphylla had very low survival (< 25%) even when raised in revegetation container grade sizes. If the quality of the planting site is high, the container size seems to be less important for most species. Other species such as Aristotelia serrata, Cordyline australis, Plagianthus regius and Podocarpus totara appear to depend more on site quality. In conclusion, nursery container systems for raising New Zealand native plants should be chosen based on the biology of the species, nursery management practices, quality of the planting site, and a balance between cost and benefit for each situation.

Snowpack in the Northern Hemisphere is gradually disappearing due to rising global temperatures. Snowmelt water is a critical water resource for vegetation in the arid areas of the Northeast Tibetan Plateau. We used a random forest model to analyze the main factors influencing tree growth and using structural equation modelling to examine the pathways through which snowpack affected vegetation growth. The results show that soil moisture, controlled by snowmelt water, dominates the radial growth of Qinghai spruce (Picea crassifolia Kom.). At the same time, snow melt on vegetation is affected by both elevation and land cover. Atmospheric circulation patterns regulated by North Atlantic sea surface temperatures determine spring snowpack variability in this area. In future scenarios based on the Coupled Model Intercomparison Project Phase 6 (CMIP6) simulations, snowpack will continue to decrease, presenting significant constraints to the growth of vegetation.

Nitrogen and phosphorus (NP) deposition can change the nutrient input of forest ecosystems. The effects of NP deposition on soil aggregate need to be analyzed to propose effective environmental management strategies. In this study, representative Korean pine mixed forests and Korean pine plantations in northeastern China were selected. Soil samples were sieved to obtain four different particle sizes of soil aggregates (> 2, 2–0.25, 0.25–0.053, and  < 0.053 mm). Four NP treatments were applied to simulate N and P deposition, and an indoor incubation experiment was conducted over a period of 360 d. Total nitrogen, microbial nitrogen, dissolved organic nitrogen, hydrolyzed nitrogen, NH₄⁺–N, NO₃⁻–N content, and extracellular enzyme activities of NAG, LAP, and AP were determined. Different fractions of N responded differently to NP addition. Lower NP addition had a greater promoting effect on aggregate N compared to higher NP addition. NAG was the main extracellular enzyme affecting N in both forest types. NP addition had a greater effect on the extracellular enzyme activities of the soil aggregates from the Korean pine plantations. These results enhance our understanding of the effects of NP addition on soil nitrogen within temperate forest ecosystems.

Climate change is a global phenomenon that has profound impacts on ecological dynamics and biodiversity, shaping the interactions between species and their environment. To gain a deeper understanding of the mechanisms driving climate change, phenological monitoring is essential. Traditional methods of defining phenological phases often rely on fixed thresholds. However, with the development of technology, deep learning-based classification models are now able to more accurately delineate phenological phases from images, enabling phenological monitoring. Despite the significant advancements these models have made in phenological monitoring, they still face challenges in fully capturing the complexity of biotic-environmental interactions, which can limit the fine-grained accuracy of phenological phase identification. To address this, we propose a novel deep learning model, RESformer, designed to monitor tree phenology at a fine-grained level using PhenoCam images. RESformer features a lightweight structure, making it suitable for deployment in resource-constrained environments. It incorporates a dual-branch routing mechanism that considers both global and local information, thereby improving the accuracy of phenological monitoring. To validate the effectiveness of RESformer, we conducted a case study involving 82,118 images taken over two years from four different locations in Wisconsin, focusing on the phenology of Acer. The images were classified into seven distinct phenological stages, with RESformer achieving an overall monitoring accuracy of 96.02%. Furthermore, we compared RESformer with a phenological monitoring approach based on the Green Chromatic Coordinate (GCC) index and ten popular classification models. The results showed that RESformer excelled in fine-grained monitoring, effectively capturing and identifying changes in phenological stages. This finding not only provides strong support for monitoring the phenology of Acer species but also offers valuable insights for understanding ecological trends and developing more effective ecosystem conservation and management strategies.

Tropical forests, critical for global carbon storage and biodiversity, are failing to adapt at the pace required by accelerating climate change. A comprehensive study by Aguirre-Gutiérrez et al. (Science 387:eadi5414, 2025) analyzing four decades of data from 415 forest plots and 250,000 trees across the Americas reveals significant mismatches between functional trait shifts (e.g., leaf area, wood density, photosynthetic capacity) and climatic pressures. Survivor trees tracked climatic changes at less than 8% of the necessary rate, while recruits achieved only 22%, leaving ecosystems increasingly vulnerable. Lowland forests exhibited stronger trait responses compared to nutrient-limited montane forests, but neither aligned with future climate projections. By 2100, projected temperature rises (~ 4 °C) and precipitation declines (~ 20%) may push forests into “no-analog” climates, surpassing adaptive thresholds. These lags threaten carbon sequestration, biodiversity, and ecosystem stability, underscoring the urgent need for emissions reduction, conservation of climate refugia, and assisted migration strategies to mitigate irreversible biome transitions.

Both abiotic conditions and management influence the success of forest restoration. Despite growing interest and practical effort in restoring degraded forest landscapes, understanding of how disparate factors, such as terrain, soil conditions, climate and silvicultural treatments, directly or collectively control species performance and shape community recovery remains limited. In this study, we assessed how topography and management intervention affect seedling survival and growth in the early stages of restoration. To do so, we established seven experimental plots, each measuring 20 m × 20 m (400 m²) subdivided into 48 subplots, in coarse, anthropogenic grassland on a mid-elevation mountain slope in Hong Kong, and planted a total of 3975 native tree seedlings belonging to 12 tree species within them. To characterise topography, we modelled the elevation, slope, convexity and aspect of each subplot. Two types of tree guard (enclosed blue plastic sleeve and open yellow mesh), two types of fertiliser (organic and inorganic) and cardboard weeding mats were used to assess the impact of management interventions on the establishment of the seedlings. Survivorship, height and basal diameter were measured at 1, 2 and 4 years after planting. We used generalised linear models to examine the effect of these factors and their interactions on seedling survival, and we applied linear models and hierarchical partitioning to explore their relative importance in determining the relative growth rate (RGR) of each species. The most parsimonious models were selected using the Akaike Information Criterion. Survivorship was 98.1%, 95.2% and 86.4% across all plots in the first, second and fourth year, respectively. On average, topographic and management variables explained 1.48–3.34% of total variation in RGR, respectively, for all species. The models revealed that type of tree guard, aspect and elevation were the most important factors explaining RGR and survival. Results of hierarchical partitioning by species and growth period showed that the key determinants of performance vary by species and shift over the course of early seedling establishment, emphasising the importance of both spatial and temporal scales in the restoration of degraded tropical forests. Our findings support the use of enclosed tree guards and fertiliser to improve survivorship and growth across a range of broadleaved Asiatic species. All potential limiting factors pertaining to both site factors and management, as well as their interactions, should be considered in restoration planning to maximise restoration success.

The influence of global climate change on endangered species is of growing concern, especially for rosewood species that are in urgent need of protection and restoration. Ecological niche models are commonly used to evaluate probable species’ distribution under climate change and contribute to decision-making to define efficient management strategies. A model was developed to forecast which habitat was most likely appropriate for the Dalbergia odorifera. We screened the main climatic variables that describe the current geographic distribution of the species based on maximum entropy modelling (Maxent). We subsequently assessed its potential future distribution under moderate (RCP_2.6) and severe (RCP_8.5) climate change scenarios for the years 2050 and 2070. The precipitation ranges of the wettest month and the warmest quarter are the primary limiting factors for the current distribution of D. odorifera among the climatic predictors. Climate change will be expected to have beneficial effects on the distribution range of D. odorifera. In conclusion, the main limits for the distribution of D. odorifera are determined by the level of precipitation and human activities. The results of this study indicate that the coasts of southern China and Chongqing will play a key role in the protection and restoration of D. odorifera in the future.

Forests play a vital role in mitigating climate change through their physiological functions and metabolic processes, including their ability to convert solar energy into biomolecules. However, further research is necessary to elucidate how structural characteristics of a forest and topographic settings influence energy conversion and surface temperature of a forest. In this study, we investigated a beech forest in central Germany using airborne laser scanning (ALS) point cloud data and land surface temperature (LST) data derived from Landsat 9 satellite imagery. We constructed 30 m × 30 m plots across the study area (approximately 17 km²) to align the spatial resolution of the satellite imagery with the ALS data. We analyzed topographic variables (surface elevation, aspect and slope), forest attributes (canopy cover, canopy height, and woody area index), as well as forest structural complexity, quantified by the box-dimension (D_b). Our analysis revealed that LST is significantly influenced by both forest attributes and topographic variables. A multiple linear regression model demonstrated an inverse relationship (R² = 0.38, AIC = 8105) between LST and a combination of D_b, elevation, slope, and aspect. However, the model residuals exhibited significant spatial dependency, as indicated by Moran’s I test. To address this, we applied a spatial autoregressive model, which effectively accounted for spatial autocorrelation and improved the model fit (AIC = 746). Our findings indicate that elevation exerts the most substantial influence on LST, followed by forest structural complexity, slope, and aspect. We conclude that forest management practices that enhance structural complexity can effectively reduce land surface temperatures in forested landscapes.

The predominant causal agent of poplar leaf blight is the pathogenic fungus Alternaria alternata (Fr.) Keissl., which exhibits host specificity toward Populus species. To elucidate the molecular response mechanisms of A. alternata under fludioxonil fungicide stress, the fungus was cultured at the half-maximal effective concentration (EC₅₀) of fludioxonil. Transcriptomic and metabolomic profiles were analyzed using mycelia harvested under these conditions. Comparative analysis revealed 1,001 differentially expressed genes (DEGs) in the resistant strain (RS) relative to the wild-type strain (WT), comprising 628 upregulated and 373 downregulated genes. Concurrently, 524 differentially accumulated metabolites (DAMs) were identified, with 336 upregulated and 188 downregulated metabolites. KEGG pathway enrichment demonstrated pronounced upregulation in glycerophospholipid metabolism, α-linolenic acid metabolism, nucleic acid biosynthesis, and glycosylation processes. Conversely, arachidonic acid and galactose metabolism pathways were suppressed. Significant downregulation was observed in phosphatidylinositol signaling, aflatoxin biosynthesis, and cutin/suberin/wax biosynthesis pathways. Transcriptomic profiling further indicated that upregulated DEGs were predominantly associated with amino sugar/nucleotide sugar metabolism, ABC transporters, aflatoxin biosynthesis, and purine metabolism, while downregulated DEGs were enriched in N-glycan biosynthesis, endoplasmic reticulum protein processing, steroid biosynthesis, and riboflavin metabolism. Fludioxonil exerted substantial inhibitory effects on fungal growth, pathogenicity, and metabolic activity. Mechanistically, A. alternata counteracted fungicide-induced stress through modulation of its antioxidant defense system. This integrative multi-omics study delineates the dynamic gene expression and metabolic reprogramming in A. alternata under fludioxonil exposure, providing novel insights into potential molecular targets and informing the development of next-generation fungicidal strategies for phytopathogen control.

South Florida’s natural forest ecosystems, including pine rocklands and hardwood hammocks, are threatened by land use change and urbanization, invasive species, and climate change. It is critical to understand the responses of these ecosystems to anthropogenic disturbances to conserve the remnants of the USA natural subtropical forests. Using dendrochronology, long-term growth patterns were characterized in three dominant native tree species: Bursera simaruba, Swietenia mahagoni, and Pinus elliottii. Core samples were collected from > 30 individuals of each species in hardwood hammocks (B. simaruba and S. mahagoni) and pine rocklands (P. elliottii) to examine growth patterns. Relationships between annual tree growth rates and climatic variables were assessed to address three questions: (1) What are the climatic drivers of growth in these three South Florida tree species? (2) Are their growth rates stable or changing through time? and (3) Are tree growth rates affected by urbanization? Standardized growth rates of the three species have changed through time, with small young trees showing accelerated growth through time, whereas larger, older trees showed declining growth rates. S. mahagoni and B. simaruba grew faster in urbanized parks than in more natural parks, whereas P. elliottii grew slower in urban parks. There were positive correlations between tree growth and the current year’s fall precipitation and no discernable effects of the current year’s monthly temperatures on growth rates of any of the species. These results suggest that the foundational tree species of the southern USA endangered pine rocklands and hardwood hammocks may be vulnerable to ongoing changes in precipitation and temperature as well as other environmental effects associated with urbanization.

Forest inventory is increasingly producing information on the locations and sizes of individual trees. This information can be acquired by airborne or terrestrial laser scanning or analyzing photogrammetric data. However, all trees are seldom detected, especially in young, dense, or multi-layered stands. On the other hand, the complete size distributions of trees can be predicted with various methods, for instance, kNN data imputation in an area-based LiDAR inventory, predicting the parameters of a distribution function from remote sensing data, field sampling, or using histogram matching and calibration methods. The predicted distribution can be used to estimate the number and sizes of the non-detected trees. The study’s objective was to develop a method for forest planning that efficiently uses the available tree-level data in management optimization. The study developed a two-stage hierarchical method for tree-level management optimization for cases where only part of the trees is detected or measured individually. Cutting years and harvest rate curves for the non-detected trees are optimized at the higher level, and the cutting events of the detected trees are optimized at the lower level. The study used differential evolution at the higher level and simulated annealing at the lower level. The method was tested and demonstrated in even-aged Larix olgensis plantations in the Heilongjiang province of China. The optimizations showed that optimizing the harvest decisions at the tree level improves the profitability of management compared to optimizations in which only the dependence of thinning intensity on tree diameter is optimized. The approach demonstrated in this study provides feasible options for tree-level forest planning based on LiDAR inventories. The method is immediately applicable to forestry practice, especially in plantations.

The growth of Sakhalin fir (Abies sachalinensis) seedlings, an important forest tree species in northern Hokkaido, Japan, is significantly affected by competition from surrounding vegetation, especially evergreen dwarf bamboo. In this study, we investigated the height and root collar diameter (RCD) growth of Sakhalin fir seedlings under various degrees of cover by deciduous vegetation and evergreen dwarf bamboo. Generalized additive models were used to quantify the effects of canopy cover and forest floor cover on the relative growth rates of these two parameters. The canopy cover of Sakhalin fir seedlings had a nonlinear negative effect on both the height growth of seedlings in the subsequent year and the RCD growth in the current year, given the general growth pattern in this species, where height growth ceases in early summer and RCD growth continues until autumn. Height growth declined sharply after the canopy cover rate exceeded 50%, while RCD growth declined rapidly between 0 and 50% canopy cover rate. The forest floor cover had a greater negative impact on RCD growth than on height growth. These results suggested that Sakhalin fir seedlings respond to vegetative competition by prioritizing height growth for light acquisition at the expense of diameter growth and possibly root growth for belowground competition. The cover of evergreen dwarf bamboo reduced the height growth of fir seedlings significantly more than the cover of deciduous vegetation. This difference is likely due to the timing of light availability. When competing with deciduous vegetation, Sakhalin fir seedlings exposed to light during the post-snow melt and early spring before the development of the deciduous vegetation canopy can photosynthesize more effectively, leading to greater height growth. The results of this study highlighted the importance of vegetation control considering the type of vegetation for successful Sakhalin fir reforestation. Adjusting the intensity and timing of weeding based on the presence and abundance of dwarf bamboo and other competing vegetation could potentially reduce weeding costs and increase biodiversity in reforested areas.

Climate change has significantly increased the frequency and severity of droughts and risk of tree death worldwide. Differences in leaf habit, plant size, and species diversity are associated with differences in the risk of drought-induced mortality, but the relative contributions of these factors to the risk of mortality are unclear. In a study of the mortality of tree and shrub species during the extreme drought of 2019 in a savanna ecosystem in Southwest China, we assessed the relative contributions of evergreen and deciduous leaf habit, plant size, and species richness and diversity to the mortality of shrubs and trees after the 2019 extreme drought. The deciduous species had significantly lower hydraulic safety margins than the coexisting evergreen species, resulting in a higher mortality risk. Additionally, species and individuals with taller canopies tended to have deeper root systems, an advantage during extreme drought that reduced mortality risk. Notably, mortality risk was largely independent of stand species richness and diversity. Overall, leaf habit and plant height were better predictors of mortality risk than species richness and diversity. These novel insights provide a better understanding of the mechanisms driving drought-induced mortality in the ecosystems with a low canopy and weak interspecific and intraspecific competition for shared resources. Leaf habit and tree size should be incorporated into hypotheses on the mechanisms underlying drought-induced tree mortality.

Accurately forecasting ecosystem services is critical for enhancing our understanding and improving management practices within nature reserves, particularly in light of climate change, land use/cover changes, and their complex interactions. However, existing studies often fail to fully consider vegetation response, constituting a gap in the comprehensive assessment of changes in ecosystem services. Therefore, a coupled model framework integrating climate change, land use change, and vegetation dynamics was developed to allow for the simulation of dynamic ecosystem service scenarios throughout the twenty-first century. The Jiulianshan National Nature Reserve in Jiangxi Province was considered as the study area. The results showed that ecosystem services and their synergistic effects will be optimized under scenarios that emphasize strict protection of ecological lands and incorporating the SSP1-2.6 scenario. However, sustaining optimized ecosystem services poses significant challenges in scenarios characterized by resource-intensive development and ongoing climate warming, as in the SSP5-8.5 scenario. Notably, discernible variations exist in balancing and synergizing the management of ecosystem services across diverse land uses and forest types. Our study underscores the importance of integrating vegetation response into the framework of ecosystem service forecasting, which is essential for assisting nature reserves in effectively addressing the multifaceted risks associated with climate change and rapid socio-economic development.

Eucalyptus urophylla ×  E. grandis is a major hybrid species of timber plantations. However, our understanding of Eucalyptus mitochondrial genome, especially within the Myrtaceae family, is limited. In this study, we employed hybrid sequencing combining the Illumina and Oxford Nanopore sequencing to assemble and annotate the mitogenome (mtDNA) of E. urophylla ×  E. grandis. Our results reveal a structure characterized by one circular molecule, with a cumulative length of 483,907 base pairs (bp) and a GC content of 44.96%. The circular molecule collectively harbored 59 annotated genes. Among these, 38 were unique protein-coding genes (PCGs), accompanied by 18 transfer RNA (tRNA) genes and 3 ribosomal RNA (rRNA) genes. Our study also examined repetitive sequences, RNA editing sites, and intracellular sequence transfers within the mtDNA. Furthermore, we conducted a phylogenetic analysis between E. urophylla ×  E. grandis and 30 closely related species based on genetic affinities. The outcomes furnish a high-quality organelle genome for E. urophylla ×  E. grandis, thereby explaining basic insights into organelle genome evolution and phylogenetic relationships.

Fires have historically played a natural role in shaping ecosystems, contributing to biodiversity and ecological renewal. However, in the Anthropocene, the interplay of climate change and human activities has exacerbated fire frequency and intensity, with cascading impacts on soil health, biodiversity, and ecosystem resilience. This study highlights the complex effects of fire on soil ecosystems, particularly in Mediterranean environments, by analysing the aftermath of the 2021 wildfire in Aspromonte National Park. The results of this research reveal the multifaceted impact of fire on soil composition and biological activity. Burned areas exhibited altered microbial communities, characterized by a higher biomass of bacteria and actinomycetes but reduced fungal presence, aligning with findings that fungi are more sensitive to heat than other microorganisms, particularly under moist conditions. Changes in enzyme activity, such as decreased oxidoreductase and hydrolase activities but elevated catalase activity, suggest significant metabolic adjustments among surviving microbial strains. Additionally, increased potassium, magnesium, sulphates, and total phenols in burned areas point to shifts in nutrient dynamics driven by the combustion of organic matter. Fire also impacted microarthropod communities but the rapid recovery of microarthropod communities that has been recognized by numerous authors suggests that fire may not universally impair soil biodiversity in Mediterranean environments. The transition zone played a critical intermediate role, retaining a higher organic matter content than the unburned zone, suggesting its potential as a buffer or recovery zone in post-fire dynamics. Microarthropod communities, while initially affected, demonstrated resilience in line with previous research, indicating that Mediterranean soils might possess adaptive mechanisms to recover from low- to moderate-severity wildfires. Importantly, the incorporation of ashes and partially burned organic material in such fires may lead to enhanced soil fertility, fostering bacterial and actinomycetes proliferation and facilitating ecosystem recovery.

Forests play a critical role in mitigating climate change by sequestering carbon, yet their responses to environmental shifts remain complex and multifaceted. This special issue, “Tree Rings, Forest Carbon Sink, and Climate Change,” compiles 41 interdisciplinary studies exploring forest-climate interactions through dendrochronological and ecological approaches. It addresses climate reconstruction(e.g., temperature, precipitation, isotopes) using tree-ring proxies, species-specific and age-dependent growth responses to warming and drought, anatomical adaptations, and methodological innovations in isotope analysis and multi-proxy integration. Key findings reveal ENSO/AMO modulation of historical climates, elevation- and latitude-driven variability in tree resilience, contrasting carbon dynamics under stress, and projected habitat shifts for vulnerable species. The issue underscores forests’ dual role as climate archives and carbon regulators, offering insights for adaptive management and nature-based climate solutions. Contributions bridge micro-scale physiological processes to macro-scale ecological modeling, advancing sustainable strategies amid global environmental challenges.

A geomagnetic field is a significant factor during the growth and development of trees. Changes in the magnetic field (MF) will result in reactions at the biochemical, molecular, cellular and gene levels. However, it is not clear how a magnetic field affects metabolism and homeostasis under stressful conditions such as salinity. In this study, a novel method was developed of a static magnetic field (SMF) to investigate magnetobiological changes in trees. The results show that pre-treatment of poplar (Populus ×  euramericana ‘Neva’) cuttings with a static magnetic field significantly mitigated the negative effects of salinity stress on their growth and physiological activities. Biochemical assays revealed that several chemical messengers, including hydrogen peroxide (H₂O₂) and O₂^•−, were significantly improved in roots treated with salt, implying an increase reactive oxygen species. A static magnetic field also significantly increased proline concentrations, soluble protein contents, and CAT and SOD activities. Electrophysiological experiments further revealed that pre-treatment with a static magnetic field remarkably decreased salt-induced Na⁺ influx and H⁺ efflux which control plant salt tolerance. In pharmacological experiments, because the Na⁺/H⁺ correlation was closely related to the SMF-activated plasma membrane and Na⁺ antiporter activity alleviated the massive accumulation of salt-induced reactive oxygen species (ROS) within the roots. In addition, a static magnetic field dramatically increased the transcriptional activity of stress-responsive genes, including PtrRBOHD and PtrHA5. Together, these results indicate that SMF reduced Na⁺ influx by activating Na⁺/H⁺ antiporters and plasma membrane H⁺-ATPase to effectively maintain homeostasis by regulating the reactive oxygen species system and cytoplasmic osmotic potential. Ultimately, these static magnetic field methods improved salt tolerance in poplar cuttings, and, for future research, similar methods could be applied to other plants.

Over the last century, the Mediterranean basin has been widely affected by the abandonment of farming activities, leading to a natural succession towards forested ecosystems. This process is resulting in a carbon (C) stock increase at an ecosystem level, often assessed through the measurement of aboveground biomass, while the contribution of soil organic carbon (SOC) remains unclear. We investigated C changes caused by secondary succession on previously grazed areas in central Italy, specifically focusing on the SOC pool. The natural succession is described through a chronosequence approach over four successional stages: pastures, shrublands, young and mature forests. Eight replicates per stage were studied, and C stock was estimated in the mineral soil down to a 30-cm depth, and in all other ecosystem C pools: aboveground and belowground biomass, deadwood and litter. In the mature forests, SOC stock was significantly higher (p < 0.05) than in pastures by 40 ± 8 Mg ha^–1, corresponding to 28% of the total ecosystem C stock gain. The same trend was observed for aboveground biomass, the pool that increased the most (62 ± 23 Mg ha^–1), with a 43% contribution to total ecosystem gain. Our results point to a substantial contribution of SOC to overall C stock during secondary succession in Mediterranean ecosystems.

Exploring the formation and changes in tree microclimates can help improve the quality of urban green spaces. Temperature is an important indicator of microclimate, and tree temperature categories can be divided into ambient temperature and tree surface temperature (T_ts), from which the mean radiation temperature (T_mrt) and thermal comfort values are derived. In this study, the summer microclimate of Ficus altissima in southern subtropical China was determined, focusing on soil (T_s), air (T_a), globe (T_g), and T_ts. T_mrt and four commonly used thermal comfort indicators, i.e., predicted mean vote (PMV), physiologically equivalent temperature (PET), standard effective temperature (SET*), and universal thermal climate index (UTCI), were also calculated. The results showed that: (1) T_mrt can be used to explain both the cooling effect and to predict thermal comfort in the shade; (2) the PET indicator is more advantageous for analyzing thermal comfort in the microclimate of Ficus altissima; (3) T_s is not a suitable important indicator for predicting ambient temperatures and thermal comfort; and (4) the site-specific sampling method of the crowns or trunks can be used to accurately explain changes in the whole-plant thermal environment and thermal comfort, respectively.

Afforestation on formerly cultivated or abandoned agricultural land is a common strategy to increase forest areas and enhance carbon sequestration. Deep soil ploughing before afforestation improves soil conditions, facilitating tree growth and carbon storage. This study assessed the growth and biomass parameters of Pinus sylvestris in 10- and 20 years old plantations established on deeply ploughed and non-ploughed soils in Lithuania. Biomass allocation and carbon and nutrient concentrations including N, P, K, Ca and Mg were analysed in aboveground biomass components. Deep ploughing in the 10 years old stands negatively impacted vertical growth and stem development but did not significantly affect overall biomass accumulation. In contrast, in the 20 years old stands, deep ploughing resulted in taller trees with larger diameters and higher biomass accumulation compared to non-ploughed sites. Biomass distribution within tree canopies varied between ploughed and non-ploughed sites, indicating diverse effects of deep ploughing. Carbon and nutrient concentrations in biomass components showed site-specific variations, with deep ploughing influencing carbon concentrations in needles and stem bark. Overall, deep ploughing showed potential for enhancing tree growth and biomass accumulation, with implications for carbon sequestration in forest ecosystems. These findings help us understand the impact of an alternative soil management practice, deep ploughing, on forest development and carbon dynamics.

Two leaf color variants red-leaf (R-type) and common-leaf (G-type) of Euonymus sacrosancta Koidz., were employed as experimental materials to elucidate the molecular mechanisms underlying chromatic transition. Physiological profiling identified anthocyanins and flavonoids as the predominant pigments responsible for the red foliar phenotype, which exhibited reduced chlorophyll and carotenoid accumulation but elevated soluble sugars and proteins. Comparative transcriptomic analysis revealed that differentially expressed genes (DEGs) between R-type and G-type were significantly enriched in flavonoid biosynthesis and carotenoid metabolism pathways. The up-regulation of 22 key genes of anthocyanin synthesis (e.g., CHS, CHI, LAR, LDOX and UFGT) in R-type may lead to the phenotype of red leaves through the increase of anthocyanin accumulation. The downregulated expression of 13 carotenoid synthesis-related genes (e.g., PSY, PDS and VDE) and 6 carotenoid degradation genes (e.g., ABA2, CYP707A and NCED) may lead to lower carotenoid content in R-type compared to G-type. Combined with weighted gene co-expression network analysis (WGCNA), five candidate genes (EsLAR, EsLDOX, EsPDS, EsCYP707A and EsABA2) were screened from two modules highly correlated with anthocyanin content in E. sacrosancta leaves. These genes may play key regulatory roles in leaf coloration and could serve as candidate genetic resources for leaf color improvement in E. sacrosancta. Additionally, transcription factors such as C2H2s, C3Hs, and WRKYs were identified as potential regulators in the formation of R-type in E. sacrosancta. This study provides the first systematic elucidation of the transcriptional regulatory network governing red-leaf formation in E. sacrosancta, establishing a critical theoretical foundation for molecular breeding in ornamental plants.

Numerous clustering algorithms are valuable in pattern recognition in forest vegetation, with new ones continually being proposed. While some are well-known, others are underutilized in vegetation science. This study compares the performance of practical iterative reallocation algorithms with model-based clustering algorithms. The data is from forest vegetation in Virginia (United States), the Hyrcanian Forest (Asia), and European beech forests. Practical iterative reallocation algorithms were applied as non-hierarchical methods and Finite Gaussian mixture modeling was used as a model-based clustering method. Due to limitations on dimensionality in model-based clustering, principal coordinates analysis was employed to reduce the dataset’s dimensions. A log transformation was applied to achieve a normal distribution for the pseudo-species data before calculating the Bray–Curtis dissimilarity. The findings indicate that the reallocation of misclassified objects based on silhouette width (OPTSIL) with Flexible-β (– 0.25) had the highest mean among the tested clustering algorithms with Silhouette width 1 (REMOS1) with Flexible-β (– 0.25) second. However, model-based clustering performed poorly. Based on these results, it is recommended using OPTSIL with Flexible-β (– 0.25) and REMOS1 with Flexible-β (– 0.25) for forest vegetation classification instead of model-based clustering particularly for heterogeneous datasets common in forest vegetation community data.

Commercially managed forests are often poor in terms of biodiversity. Saproxylic beetle species could be a useful bioindicating group for the conservation of forest stands. In recent decades, oak stands have been affected by a wide range of factors that have intensified stand decline. Saproxylic beetle richness was investigated in declining oak stands that have been consequently targeted for clearcutting due to concerns about insect pest outbreaks. The research was conducted at six managed oak forests, where we compared beetle occurrences in declining stands and in healthy stands that did not show any symptoms of decline. Beetles were collected using window traps placed on the basal and mid-trunk sections of trees. A total of 2925 adults belonging to 239 saproxylic beetle species were captured, of which 56 species are on the IUCN Red List. The results show that declining stands were richer in saproxylic species, and that the diversity of beetle species was greater in these stands. Approximately 1.4 times more species were caught within declining stands than in healthy ones (1.6 times for Red List species). Declining stands hosted more pest species (e.g., cambiophagous and xylophagous species). However, only low numbers of these species were recorded in these stands. In summary, results of this study suggest that decline of managed oak stands is creating a wide spectrum of habitats for many saproxylic species. Thus, salvage logging of declining oak trees can represent a natural trap and reduce local beetle biodiversity, mainly for saproxylic, endangered or low-mobility species that would be attracted by new suitable habitats.

Branch length and branch diameter are important characteristics that determine wood quality and yield. Development of static branch length and diameter models by incorporating individual tree variables, site quality and competition have been widely studied, while the climate effect has rarely been reported. In this study, mixed-effects climate-sensitive branch length and diameter models were developed based on 228 sample trees of Larix kaempferi from three latitude regions in China (approximate 42°N in Liaoning Province, 33°N in Gansu Province, and 30°N in Hubei Province). Results revealed that diameter at breast height, and crown ratio, sum of the basal areas of trees larger than the subject trees, dominant tree height, mean warmest month temperature, and summer precipitation substantially improved branch length model. Diameter at breast height, and crown ratio, ratio of the sum of DBH in sample plot to the subject tree, dominant tree height, mean warmest month temperature, and spring precipitation significantly improved branch diameter model. Compared with base model, mean square error reduction of mixed-effects branch length and diameter models were 32.9% and 44.1%, respectively. The relative contributions of covariates to branch length model were tree size (59.1%), site quality (25.7%), competition (13.5%), and climate (1.7%), and branch diameter model were tree size (57.0%), competition (21.9%), site quality (18.3%), and climate (2.8%). Relative contributions of covariates on branch length and diameter models from different latitude regions were different. Effects of competition on branch length model in Liaoning and Hubei were larger than climate, whereas climate in Gansu was larger than competition. As for branch diameter model, competition in Liaoning was larger than site quality, whereas site quality in Hubei and Gansu was larger than competition. The present study strengthened the importance of considering climate variables in developing branch length and diameter model. It is desirable to disentangle the different sources of variations in affecting branch length and diameter from different latitude regions to reduce the uncertainty in predicting branch characteristics under the condition of climate changing.

Sessile oak (Quercus petraea (Matt.) Liebl.) is widely distributed across most of Europe particularly the hills and lower mountain ranges, so is considered “the oak of the mountains”. This species grows on a wide variety of soils and at altitudes ranging from sea level to 2200 m, especially in Atlantic and sub-Mediterranean climates, and it is sensitive to low winter temperatures, early and late frosts, as well as high summer temperatures. Sessile oak forms both pure and mixed stands especially with broadleaves such as European beech, European hornbeam, small-leaved lime and Acer spp. These form the understorey of sessile oak stands, promoting the natural shedding of lower branches of the oak and protecting the trunk against epicormic branches. Sessile oak is a long-lived, light-demanding and wind-firm species, owing to its taproot and heart-shaped root system. Its timber, one of the most valuable in Europe, is important for furniture-making (both solid wood and veneer), construction, barrels, railway sleepers, and is also used as fuelwood. It is one of the few major tree species in Europe that is regenerated by seed (naturally or artificially) and by stump shoots in high forest, coppice-with-standards and coppice forests. Sessile oak forests are treated in both regular and irregular systems involving silvicultural techniques such as uniform shelterwood, group shelterwood, irregular shelterwood, irregular high forest, coppice-with-standards and simple coppice. Young naturally regenerated stands are managed by weeding, release cutting and cleaning-respacing, keeping the stands quite dense for good natural pruning. Plantations are based on (1) 2–4-year old bare-root or container-grown seedlings produced in nurseries using seeds from genetic resources, seed stands and seed orchards. The density of sessile oak plantations (mostly in rows, but also in clusters) is usually between 4000 and 6000 plants ha⁻¹. Sessile oak silviculture of mature stands includes crown thinning, focusing on final crop trees (usually a maximum of 100 individuals ha⁻¹) and targeting the production of large-diameter and high quality trees at long rotation ages (mostly over 120 years, sometimes 250–300 years). In different parts of Europe, conversion of simple coppices and coppice-with-standards to high forests is continuing. Even though management of sessile oak forests is very intensive and expensive, requiring active human intervention, the importance of this species in future European forests will increase in the context of climate change due to its high resistance to disturbance, superior drought tolerance and heat stress resistance.

The current trends in forestry in Europe include the increased use of continuous cover forestry (CCF) and the increased availability of tree-level forest inventory data. Accordingly, recent literature suggests methodologies for optimizing the harvest decisions at the tree level. Using tree-level optimization for all trees of the stand is computationally demanding. This study proposed a two-level optimization method for CCF where the harvest prescriptions are optimized at the tree level for only a part of the trees or the first cuttings. The higher-level algorithm optimizes the cutting years and the harvest rates of those diameter classes for which tree-level optimization is not used. The lower-level algorithm allocates the individually optimized trees to different cutting events. The most detailed problem formulations, employing much tree-level optimization, resulted in the highest net present value and longest optimization time. However, restricting tree-level optimization to the largest trees and first cuttings did not significantly alter the time, intensity, or type of first cutting. Computing times could also be shortened by applying accumulated knowledge from previous optimizations, implementing learning aspects in heuristic search, and optimizing the search algorithms for short computing time and good-quality solutions.

Climate changes in cold-temperate zones are increasingly altering the state of climatic constraints on photosynthesis and growth, leading to adaptive changes in plant phenology and subsequent seasonal carbon assimilation. However, the spatio-temporal patterns of climatic constraints and seasonal carbon assimilation are poorly understood. In this study, the timing of peak photosynthetic activity (DOY_pmax) was employed as a proxy for plant adaptive state to climatic constraints on growth to examine the spatio-temporal dynamics of DOY_pmax. By using multiple remote sensing metrics, DOY_pmax was characterized with changes in the solar-induced chlorophyll fluorescence (SIF) and leaf area index (LAI) from 2000 to 2018. Based on SIF, the DOY_pmax was generally around day 190, while based on LAI was about 10 d later. Peak photosynthetic activity of forests occurs earlier compared to other vegetation types. Overall, the advanced DOY_pmax were observed based on both SIF and LAI, with annual rates of 0.2 (P = 0.31) and 0.3 (P < 0.05) d, respectively. DOY_pmax dynamics were influenced by hot temperature extremes and vapor pressure deficits (VPD) during the early growing season, regardless of sub-zone and different vegetation type. The generalized linear mixed model (GLMM) showed the largest contribution by hot extremes to DOY_pmax dynamics accounted for 55.5% (DOY_{pmax_SIF}) and 49.1% (DOY_{pmax_LAI}), respectively, followed by VPD (DOY_{pmax_SIF}: 23.1%; DOY_{pmax_LAI}: 29.5%). These findings highlight the crucial role of climate extremes in shaping seasonal carbon dynamics and regional carbon balance.

Land use/land cover (LULC) change monitoring is critical for understanding environmental and socioeconomic processes and to identify patterns that may affect current and future land management. Forest cover evolution in the Mediterranean region has been studied to better understand forest succession, wildfires potential, and carbon stock assessment for climate change mitigation, among other reasons. However, though multiple sources of current LULC exist, data from last century’s forest cover are less common, and are normally still reliant on locally orthophoto-interpreted data, making continuous maps of historical forest cover relatively uncommon. In this work, a pipeline based on image segmentation and random forest LULC modeling was developed to process three high resolution orthophotos (1956, 1989, and 2021) into LULC continuous land cover maps of Spain’s island of Ibiza. Next, they were combined to quantify forest evolution of Mediterranean Aleppo pine (Pinus halepensis Mill.) and to generate a continuous map of forest age classes. Our models were able to differentiate forestland with an accuracy higher than 80% in all cases, and were able to approximate forestland cover change since the mid-twentieth century, estimating 21,165 ± 252 ha (37.0 ± 0.4%) in 1956, 27,099 ± 472 ha (46.8 ± 0.8%) in 1989, and 30,195 ± 302 ha (52.8 ± 0.5%) in 2021, with a mean increase of 139 ± 6 ha (0.46 ± 0.02%, calculated from current forest cover estimate) per year. The most important variables for the identification of the forestland were the terrain slope and the image gray level or color information in all orthophotos. When combining the information from the three periods, the analysis of forest evolution revealed that a significant portion of current forest cover, approximately 15,776 ha, fell within the 75–120 year age range, while 5388 ha fell within the range of 42–74 years, and 9022 ha within the 10–41 years forest age class. Younger forests, except when mapped after known wildfires, were not considered due to the limitations of the methodology. When compared to forest age data based on ground measurements, significant differences were found among each of the remotely sensed forest age classes, with a mean difference of 13 years between the theoretical age class central value and the real observed plot average age. Overall, 63% of the forest inventory plots were assigned with the correct forest age class. This work will allow a better understanding of long-term Mediterranean forest dynamics and will help landowners and policymakers to better respond to new landscape planning challenges and achieve sustainable development goals.

Soil microbial communities play a crucial role in forest ecological processes, but the differences between rhizosphere and non-rhizosphere soils, as well as their variations with stand ages remain unclear. We collected rhizosphere and non-rhizosphere soils in Castanopsis hystrix plantations at ages (6, 10, 15, 25, 30 and 34 years) in the southern subtropics and analyzed soil microbial communities using the phospholipid fatty acid (PLFA) method. There were significant differences in microbial communities between the two. Rhizosphere soils had higher total PLFAs and fungal to bacterial (F:B) ratios, and lower arbuscular mycorrhizal fungi to ectomycorrhizal fungi (AMF:EMF) ratios in the 34-year-old stand but microbial communities in non-rhizosphere soils showed no changes with stand age. Rhizosphere soils had higher total PLFAs and F:B ratios but lower AMF:EMF ratios. Further analysis revealed a strong correlation between fine root nutrients and rhizosphere soil PLFAs, indicating a closer interaction between root exudates and microbial communities. In contrast, non-rhizosphere soil PLFAs appeared to be more influenced by soil nitrogen availability. Overall, soil microbial communities exhibited significant differences between rhizosphere and non-rhizosphere soils over various stand ages. A strong correlation was observed between rhizosphere soil PLFAs and fine root nutrients, which may improve our understanding of forest management strategies.

Texas experienced the worst drought in its 100-year history in 2011, resulting in the death of approximately 300 million trees. The high number of sudden deaths had a significant impact on forest ecosystems. This study aimed to gain insight into the long-term and combined impacts of drought-induced forest tree deaths and their effects on biomass. This study used data obtained from 1797 National Forest Inventory (NFI) plots to analyze trends and major causes of changes in tree biomass at the sample plot level in East Texas forests over the past 20 years (2000 − 2019). In this study, forest trees in East Texas were divided into diameter at breast height (dbh), height, stand types, latitude, elevation, ecological zones, and FIA Unit. Principal component analysis (PCA) was also performed using drought intensity, drought duration, the four competing factor indicators, and the biomass loss rate of forest trees to better understand r drought impacts on forest trees. The results showed the lowest biomass loss rate of Pine species. Similarly, trees with shorter height and smaller dbh experienced a higher biomass loss rate. A higher biomass loss rate was observed in natural forests, West Gulf Coastal Plain and Plain and Southern East Texas ecoregion experienced higher biomass loss. Principal component analyses of drought intensity, drought duration, and the four competing metrics revealed that overall drought was the main contributor to biomass loss rates, and that drought intensity and drought duration had comparable effects on biomass loss rates.

While the fire protection function of tree bark has been extensively documented, other critical functions, including storage and mechanical support, have received less attention. In this study we examined: (1) the allometry of bark thickness (and biomass) against wood radius (and biomass) at a disc level, (2) differences in bark allocation between the ratio and the regression approaches, (3) differences between bark thickness and biomass as metrics of bark allocation, and (4) how bark allocation is associated with the evolution of wood from non-porous to diffuse-porous and ring-porous types. Thickness and biomass of bark and wood were measured using trunk discs of 88 individual trees of 36 species in a temperate forest characterized by a long fire interval. Allometric relationships of bark thickness (and biomass) against wood radius (and biomass) explained why both relative bark thickness and biomass decreased with increasing stem diameter. Variations in both among species varied by factors of 3.5 to 7.5 depending on the measurement methods. The ratio approach produced higher estimates of both relative bark thickness and biomass compared to the regression approach, while relative bark thickness was significantly lower than relative bark biomass. Ring-porous species exhibited higher bark thickness based on the ratio approach, which might reflect evolutionary adaptations where ring-porous species have developed thicker bark as protection: thermal insulation against freeze–thaw embolism coupled with carbohydrate reservoirs for hydraulic repair. The regression slope of bark allocation against wood density increased along the wood porosity gradient, demonstrating evolutionary biomechanical coordination between bark and wood. These findings highlight systematic coupling between bark and xylem multifunctionality.

The duration of snow cover has shortened in the boreal region, and the amount of seasonal snow decreased. This affects the coupling between soil and air temperatures and may thus lead to colder soil and deeper soil frost. We prevented snow reaching the forest floor for two winters in mature boreal forest and studied how that affects tree and forest floor processes. The studied species were Scots pine, Norway spruce, silver birch, and a dwarf shrub bilberry. Decreased soil temperature, due to the lack of snow cover, decreased forest floor respiration in winter and spring. Simultaneously, response of respiration to temperature seemed to increase, perhaps due to the exposure of forest floor vegetation to cold air temperature. Indeed, lack of snow cover induced mortality of bilberry, but the remaining ramets grew more in height and their average leaf size was larger likely to compensate for the lost plant biomass. Lack of snow cover also affected tree hydraulics as tree water uptake was decreased in spring, and the start of the sap season delayed in birch. Pine and birch tended to grow less in the snow exclusion treatment (differences not statistically significant), whereas spruce grew more. Coarse root traits, e.g. water content and cellular frost damages, were not affected by the snow exclusion treatment. The results of this case study increase our understanding on the effects of changing snow cover on spring-time tree and forest floor processes in mature boreal forest, but also reveal the need for further studies on mature trees.

Forest ecosystems are among the most important and play a vital role in maintaining ecological balance and supporting biodiversity. Integrated forest management (IFM) has gained prominence in European countries as a strategy to meet human needs for ecosystem services while ensuring biodiversity conservation. Given the complementary strengths of China and the European Union (EU) in forestry and the potential for collaboration, it is beneficial to compare and analyze the research status of both in IFM-related fields to provide insights into key areas and future directions for cooperation. This study employs bibliometric analysis to systematically evaluate IFM-related research status and trends between China and the EU. By examining publication trends, collaborative networks, prominent scholars, keyword co-occurrence patterns, research hotspots, and thematic clusters, providing a comprehensive overview of IFM-related research. The findings reveal that core research areas—such as forest management practices, ecosystem services, biodiversity conservation, and data-driven assessment methods—remain central to IFM-related research. In contrast, frontiers in climate change mitigation, disturbance and restoration dynamics, and multi-stakeholder governance represent critical areas for future exploration and collaboration. Our results provide areas for enhancing China-EU collaboration in future research in IFM.

The restoration of severely fragmented forests requires urgent guidance from succession theory. New theories and methods in plant functional ecology offer novel perspectives on the mechanisms that drive forest succession and productivity. Here, we established a restoration gradient of seven forest logging periods in temperate forests in China, and conducted systematic surveys on the leaf functional traits of all observed plant species, plant community structure, and soil properties. Inspired by the new concept of two-dimensional plant community traits (i.e., efficiency and quantity traits) and plant trait networks (PTNs), we explored the adaptation mechanisms of forest communities along a restoration succession and their relationship to productivity. Efficiency and quantity traits initially increased and then stabilized, whereas multi-trait relationships (MR) exhibited fluctuations, with community resource utilization efficiency increasing initially before stabilization. As expected, productivity is poorly explained by either efficiency or quantity traits alone but is substantially better explained by their joint consideration as two-dimensional community traits. Among these, the efficiency and quantity traits of leaf area and leaf dry weight can explain up to 43% of productivity. Furthermore, MR exhibit a time-lag effect on productivity. A structural equation model (SEM) with time-lag analysis showed that efficiency traits, quantity traits, MR, and soil properties explained 64% of the spatial variation in productivity during forest succession. Efficiency and quantity traits directly regulated productivity, whereas soil properties and MR indirectly regulated productivity. Our findings are the first to demonstrate the regulation mechanisms between forest succession and productivity from the framework of efficiency traits–quantity traits-MR, providing theoretical guidance and a reference for ecological restoration, and predicting the spatial variation of forest productivity, especially at small scale.

Planting genetically improved, fast-growing tree seedlings is gaining importance as a strategy to enhance forest productivity and reduce labor requirements during plantation establishment. In this study, we evaluated the early growth and survival of advanced-generation Cryptomeria japonica seedlings compared to conventional stock, under varying planting densities and cultivation methods. A field experiment was conducted over 5 years using container-grown and bare-root seedlings derived from first- and second-generation plus trees, alongside traditional seedlings. The results showed that advanced-generation seedlings exhibited higher growth in tree height, stem diameter, and crown development than traditional seedlings, particularly when planted as container stock. These seedlings also had higher survival rates, likely due to their rapid initial height growth, which reduced the risks of accidental damage during weeding operations. Wider planting intervals increased the risk of man-made injury and seedling mortality, while faster-growing seedlings were more likely to escape from competing vegetation. Our findings highlight the potential of improved seedling stock to enhance early plantation success and reduce management inputs in the critical establishment phase of forestry.

Nitrogen (N) deficiency is a critical factor limiting natural regeneration in coastal shelterbelt forests, but the influence of different N forms on seedling establishment under varying light conditions remains poorly understood. This study investigated the effects of N forms and N concentrations on Ligustrum compactum seedlings under simulated canopy gap conditions using a three-factor design: N form (NO₃^⁻-N, NH₄⁺-N, mixed N), N concentration (30 and 60 kg ha^⁻1 a^⁻1), and light intensity (30%, 60%, and 90% full sunlight). Results showed that N addition significantly promoted seedling growth, net photosynthesis rate, and water use efficiency; however, the effects varied among N forms and concentrations. Overall, NO₃⁻-N or mixed N were more favored by L. compactum seedlings; however, the N preference was altered by light intensity and N concentration. For instance, L. compactum showed greater NO₃⁻-N or mixed N preference under low and medium light intensities, while displaying more NH₄⁺-N preference under high light intensity. N concentration also affected the growth and N preference of L. compactum seedlings, but the variance explained by N concentration was lower than that of light intensity. Leaf C, N, P stoichiometry exhibited stronger correlations with seedling’s morphological trait plasticity than those of leaf gas exchange, and further analysis demonstrated that leaf C:P and N:P were the top two critical factors affecting seedling growth, indicating that the coordination and balance among C, N, P elements were more important in explaining the seedling growth under N addition. Therefore, our results clarified that the N preference of L. compactum seedlings could be altered by light intensity and revealed that leaf C, N, P ratios were stronger predictors than leaf gas exchange parameters for explaining the N effects on seedling performance. These findings demonstrated the mechanisms of light-N interactions affecting seedling performance, providing practical guidance for optimizing N fertilization and improving natural regeneration in canopy gaps of degraded coastal shelterbelt forests.

Radial growth of trees is highly sensitive to environmental changes, but the effect of climate on tree rings in Qinghai spruce (Picea crassifolia), a widely distributed endemic conifer in western China, is more complex than in many other conifers. A comprehensive understanding of the spatiotemporal climatic responses of its rings is needed to develop theoretical basis for designing strategies for its conservation and management. Here, our synthesis of the literature on responses of radial growth of Qinghai spruce to monthly climate variables in different environmental conditions by meta-analysis showed that precipitation and drought severity are the main limiting factors for Qinghai spruce radial growth in the semiarid region of northwestern China. In warmer and drier areas, radial growth of Qinghai spruce is mainly limited by drought. In the areas north of the 600-mm annual precipitation isoline, the tree-ring width (TRW) was significantly positively correlated with precipitation and significantly negatively correlated with temperature during the growing season (June–August). The limiting effect of drought on Qinghai spruce is also gradually increasing from southeast to northwest, to the west of 103° E and within 37° N–39° N.

Forest ecosystems are critical to ecological stability, yet their functionality is increasingly threatened by the growing frequency of drought, particularly in arid and semi-arid regions. While afforestation enhances forest cover in these areas, the capacity of planted forests to adapt to climate change is poorly understood. This study examines the drought resistance and adaptive capacity of planted and naturally growing Schrenk spruce (Picea schrenkiana Fisch. & C. A. Mey.) in the Ili River Basin, Xinjiang, China using tree-ring analysis. The results indicate that natural stands have a stronger correlation with meteorological factors than plantations. Over the past 50 years, significant growth declines occurred during 1995–1997, 2007–2009, and 2012–2014, with natural forests showing a greater frequency and severity of declines compared to plantations. Planted stands demonstrated greater resistance to drought, whereas natural forests had higher resilience and recovery. Over time, natural forests have shown declining resistance to drought but increased resilience and recovery. Conversely, plantations showed declines in resistance and recovery but an increased capacity for recovery. Older natural forests are more prone to growth decline, while structurally simpler planted forests show stronger drought resistance. However, following periods of drought, natural forests demonstrated a stronger capacity for recovery. These findings provide valuable insights into the response of P. schrenkiana to climate change and offer support for the sustainable management and conservation of forest ecosystems in the Xinjiang region of China.

Norway spruce (Picea abies (L.) Karst.) in the Harz Mountains National Park (Germany) has experienced widespread mortality (> 97% of trees in the study stands) due to infestation with the large spruce bark beetle (Ips typographus L.). The dead trees (snags) remain standing in the forest for 2–5 years before harvesting. It is important to identify trees that can still produce quality timber, which may be achieved by examining their outer appearance using selected characteristics. The aim of this study was to identify possible correlations between the standing storage duration and defined external characteristics of the snags. The mean tree height at compartment level was calculated using a vegetation height model, based on light detection and ranging data from 2018, to derive the stem breakage proportion. The condition of the crown and the bark and presence of fungi, wood rot, stem cracks and bark stripping damage were also assessed. The majority of the snags were broken at least once. Windthrows were less likely compared to living spruce trees because of reduced resistance to the wind as a result of needle loss and breakage. The mean stem breakage proportion increased significantly with the duration of the standing storage; however, prolonged storage durations did not always lead to complete breakage. The occurrence of fungal fruiting bodies was significantly correlated with a higher proportion of stem breakage, and the longer the storage, the more snags had fungal fruiting bodies. The condition of the crown, assessed by the presence of branchlets, was a good indicator of the duration of the standing storage. If trees had few or no branchlets, they had been standing for at least 4 years. Overall, this initial description of the external appearance of spruce trees that have been stored standing for many years suggests that time significantly influences the tree condition and breakage intensity, which is reflected by certain tree characteristics. Future studies should examine these aspects in greater depth, particularly with regard to utilization options and safety during timber harvesting.

This study looks at the impact of climate change on the future distribution of Taxus baccata L., a species under threat. It examines how altitudinal changes may influence distribution, projecting scenarios to 2100 using the SSPs 585 SSPs 245 scenarios in 20-year intervals. The results show a contraction in distribution in areas such as in Iceland and the United Kingdom, with certain extreme points disappearing. Simultaneously, new suitable areas are expected to emerge in select regions of Asia. The study underscores the significant changes anticipated in the distribution of T. baccata due to global climate change. It suggests that the threshold for addressing climate change on this particular species has been exceeded, and emphasizes the need for concerted efforts to mitigate and adapt to climate change impacts on ecosystems and organisms. As climate change affects various aspects of life, the study advocates for sector-wide plans. These would include efficient resource utilization, selecting genotypes for afforestation of this species with lower water requirements, incorporating climate change predictions into management plans, conserving biological and genetic diversity, and developing in-situ and ex-situ conservation strategies. Anticipation of future climate changes and corresponding measures in response are crucial to minimizing the impact on this species. The study recommends establishing mixed forests composed of species resilient to a range of climate scenarios, thereby enhancing forest continuity across regions with varying degrees of climate impact. Genetic diversity is an important defense mechanism important to preserving it. Global climate change will result in significant alterations in the distribution of certain species, potentially causing population declines. Intervention is required to support the adaptation of vulnerable species, necessitating forward-looking strategies that anticipate shifts in their habitat suitability. This study emphasizes the implications of climate change for T. baccata and underscores the urgency of targeted conservation efforts to protect its populations and ensure long-term persistence.

Tree plantations in the tropical-subtropical transition zone (TSTZ) represent crucial ecological regions where diverse biomes converge. Investigating the carbon sequestration potential and dynamic changes within these plantation ecosystems is of considerable ecological significance. However, the spatial distribution, driving factors, and underlying mechanisms of carbon sequestration in plantations in this region are poorly understood, thereby limiting accurate assessments of their carbon sequestration potential. This study examines four types of plantation forests located within the TSTZ on the Puwen forest farm of Xishuangbanna, China. Two slope gradients were established to quantify and compare the rate of carbon sequestration across these ecosystems. Using random forest modeling and structural equation modeling, the study identifies key environmental factors influencing the rate of carbon sequestration in the plantations. The results reveal substantial variation in DBH growth rates, biomass carbon sequestration, and soil organic carbon sequestration rates (R_SOC) among the four forest types. Critical factors affecting R_SOC include leaf nitrogen and phosphorus concentrations (LP), total soil nitrogen (STN), total soil phosphorus (STP), soil available phosphorus, and nitrogen concentration in ground surface litter. Among these, STN and STP exerted positive effects on R_SOC, while LP is exerted negative. Overall, the concentration of soil carbon, nitrogen and phosphorus, along with the nitrogen and phosphorus levels in leaves, under different species and topographic slopes, play decisive roles in regulating soil carbon sequestration rates in tropical and subtropical plantations. This research provides support for vegetation protection and restoration in ecologically sensitive areas and watersheds, contributing to the enhancement of regional forest carbon sequestration capacity.

Although Quercus mongolica is a widely distributed, economically and ecologically important deciduous tree in northern China, models to accurately predict stand growth at a regional scale are limited. The physiological process model (3-PG) has the potential to predict stand growth dynamics under varying site conditions and climate change scenarios. Here, we used field inventory, tree ring sampling, and Bayesian calibration to parameterize a model for Q. mongolica. Stand volume and productivity were then predicted under present conditions and three future climate scenarios (RCP26, RCP45 and RCP85). Our results demonstrated that after Bayesian calibration, the posterior ranges of the sensitivity parameters aphaCx, wSx1000 and pRn accounted for 34%, 45% and 65%, respectively, of their prior range. Calibration and validation results revealed a strong correlation between predicted and measured values (R² > 0.87, P < 0.01), with < 20% bias for all growth indicators. Stand volume was projected to increase by 145% and productivity by 80% by the year 2100 under the RCP85 scenario, although these projections may vary across regions. The present study developed a tailored set of 3-PG model parameters for Q. mongolica, based on a comprehensive range of climate conditions, stand structure, and age classes. These parameters offer a scientific basis to accurately predict growth of other monospecific oak or mixed-species stands.

Biodiversity has always been valued by ecology, Diversity is generally believed to lead to stability, and biodiversity is an important condition for ecosystems to maintain health. So what factors are related to forest ecosystem biodiversity, and what kind of forest structure affects and determines the size of biodiversity. This study proposes the concept of contained uniformity based on the theory of uniformity, and uses the convergence of contained uniformity to obtain the judgment model of the forest station pattern type. At the same time, it proposes the concept of forest ecosystem distance diversity, and uses the judgment model of the stand pattern type to derive the mathematical definition of forest ecosystem distance diversity. Combining the ecological characteristics of different stand patterns and measurement indicators of forest ecosystem biodiversity, the connection between forest ecosystem distance diversity and biodiversity is derived, and this is used as an indicator to evaluate forest ecosystem biodiversity. Forest ecosystem distance diversity, as an indicator of biodiversity, can not only conduct early assessment and prediction of the biodiversity of immature forests (forests in the early succession or recovery stage), but also provide a quantitative basis for forest structure optimization. Ultimately realize the sustainable development of forestry production and operation and biodiversity protection.

Stress in plants refers to adverse changes in their functioning. The occurrence and intensity of a stress can be assessed by alterations in plant traits, termed stress indicators. The ultimate goal of this study was to test whether six morpho-physiological plant traits, frequently used as stress indicators, respond consistently across species to various environmental stressors, with the aim of detecting universal stress indicators in forest tree species. We examined changes in vertical increment, leaf/needle size, shoot length, needle longevity, photosynthetic efficiency and fluctuating asymmetry in three common European tree species, mountain birch (Betula pubescens var. pumila), Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) along three environmental gradients (elevation, pollution and seashore) from forests to stressful open environments. Data were collected in 2003, 2004 and 2005 from 297 trees growing naturally across 36 sites in north-western Russia. Fluctuating asymmetry was the only trait that did not vary among sites with differing levels of environmental stress. Leaf/needle size and shoot length occasionally changed along stress gradients, but the magnitude and direction of these changes differed by gradient type and species, resulting in no significant overall stress effect for either trait. In contrast, photosynthetic efficiency, vertical increment and needle longevity consistently decreased from low-stress to high-stress sites. The overall effect was significant for each of these three traits despite the magnitudes of these decreases differed depending on the gradient type and location, species, study year and individual tree. Replication at spatial, temporal and taxonomic levels ensured the robustness and reliability of our results that photosynthetic efficiency, vertical growth and needle longevity reliably captured a general stress syndrome and may serve as stress indicators in forest species.

Spring phenology is one of the most sensitive ecological indicators of forest responses to climate warming. Understanding the precise climatic drivers of bud break in keystone species is crucial for developing robust phenological models and predicting future ecological and economic impacts. In this study, spring bud phenology was recorded 2020–2022 of 42 provenances of sugar maple (Acer saccharum Marsh.) originating from the northern range of the species in Quebec, Canada. The effect of temperature on budburst timing was assessed, and based on the observed linear relationship, we reconstructed the budburst timings of maple forests located between 45° and 49°N latitude and –70° and –76°W longitude over the past two decades. In the common garden the entire bud break process lasted between 20 and 40 d. Bud swelling occurred mid-April to mid-May, on average 5 d earlier in the southern and warmer stands. A strong correlation was observed between bud swelling dates and mean temperatures in the last two weeks of April, with temperature explaining 90% of the variance. An increase of 1 °C in mean temperature during this period advanced budburst by 4 d. At the northern limit of sugar maple, late April had an average temperature between 1.6 and 8.7 ℃ during 2003–2022, resulting in an estimated variability of 28 d in bud swelling from early April to early May. Our findings confirm that late April temperatures play a major role in the reactivation of sugar maple at its northern range. The earlier onset of leaf development under warming conditions could increase the risk of late frost damage, with consequences for maple syrup production and species distribution.

The ectomycorrhizal fungus Paxillus involutus was inoculated onto tissue-cultures of the hybrid poplar, Populus davidiana ×  P. bolleana, to evaluate the elemental defense effect to heavy metals copper and cadmium at different concentrations by simulating Alternaria alternata fungus infection. The enrichment capacity of Populus davidiana ×  P. bolleana for Cu and Cd was closely associated with the degree of heavy metal stress. There was a significant positive interaction of applying Cu and Cd and the inoculation with P. involutus on A. alternata leaf blight disease index. The incidence rate and disease index of leaf blight underwent a significant reduction compared with the controls. Similarly, the ratio of the area of disease spot to leaf area, incidence rate, and disease index for Populus davidiana ×  P. bolleana leaves inoculated with Paxillus involutus (Batsch) Fr. were significantly lower than those of their non-mycorrhizal counterparts. With increasing the degree of Cu and Cd stress, a gradual increase in the average value of the membership function for the incidence rate and disease index was observed, indicating the weakened pathogen’s ability to cause infection and the improved resistance of Populus davidiana ×  P. bolleana to leaf blight disease under Cu and Cd stress. Moreover, superoxide dismutase enzyme activity in Populus davidiana ×  P. bolleana increased significantly, reaching levels of 411.0 U/g FW and 421.6 U/g FW under Cu and Cd treatments, respectively. These changes in metabolic products and antioxidant enzyme activities suggest that P. involutus may enhance the resistance of Populus davidiana ×  P. bolleana to the fungus, Alternaria alternata Fr. Keissel under heavy metal stress by modulating these physiological indicators.

Upper Andean tropical forests are renowned for their extraordinary biodiversity and heterogeneous environmental conditions. Despite the critical role of litter decomposition in carbon and nutrient cycles, its dynamics in this region remains unexplored at finer scales. This study investigates how microsite conditions influence litter decomposition of 15 upper Andean species over time. A reciprocal translocation field experiment was conducted over 18 months in 14 permanent plots within four sites in Colombian Andean mountain forests. Each plot contained three litterbeds (microsites), each with the 15 species, harvested at 3, 6, 12 and 18 months, totaling 2520 litterbags. Different forest variables, including canopy openness, leaf area index, slope and depth of litter, were measured in each litterbed. ANOVAs and linear mixed models were used to assess variation between sites and plots respectively, while multiple linear regression analyses evaluated the effects of forest variables on decay rates over time at the microsite scale. Results showed differences in absolute decay rates between sites but consistent relative decay rates, indicating varying magnitudes of decomposition, yet maintaining the same order based on their litter quality. Decay rates varied between species, with more variation in labile species compared to recalcitrant ones. Despite substantial variation in forest characteristics within sites, their influence on litter decomposition was minimal and declined over time. This suggests that, at finer spatial scales, the forest microenvironment plays a lesser role in litter decomposition, with litter quality emerging as the primary driver. This study is a step towards understanding the fine-scale dynamics of litter decomposition in upper Andean tropical forests, highlighting the intricate interplay between microenvironmental factors and decomposition processes.

Xishui National Forest Park in Heilongjiang Province hosts China’s most pristine temperate forests and serves as a key site for ecotourism and forest therapy. However, the emission patterns of phytoncides (key bioactive compounds) remain poorly understood, limiting their therapeutic application. This study provides the first comprehensive characterization of spatiotemporal dynamics in airborne phytoncides and their synergistic interactions with environmental factors throughout the autumn-early spring seasonal transition in a temperate forest ecosystem. We analyzed the compositional dynamics of phytoncides and terpenoid content variations using thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) from September 2024 to March 2025. This period encompassed seasonal transitions from autumn to early spring, including diurnal variations in September and snowfall events in November. The method demonstrated detection limits (LODs) ranging from 1.35 to 5.33 ng m⁻³ and quantification limits (LOQs) from 4.09 to 16.15 ng m⁻³. Our results revealed pronounced seasonal fluctuations in phytoncide composition. In September, terpenoids, esters, alcohols, and alkanes displayed a diurnal “decrease-increase” trend, whereas aldehydes and ketones peaked at midday. Notably, esters and alcohols were undetectable in November and January. By January, terpenoids reached their lowest proportion (0.17 ± 0.02%) at noon. Five terpenoids (α-pinene, myrcene, D-limonene, camphene, p-cymene) were detected in September, four (α-pinene, D-limonene, camphene, p-cymene) in November, two (D-limonene, p-cymene) in January, and only p-cymene in March. The total concentration and emission rate of the five terpenoids peaked in September afternoons at 1961.58 ± 106.67 ng m⁻³ and 653.86 ± 35.56 ng m⁻³ h⁻¹, respectively. Nocturnal emissions (32131.95 ± 2522.21 ng m⁻³) significantly surpassed daytime levels (14473.04 ± 958.49 ng m⁻³), with emission rates escalating from 1447.30 ± 95.85 ng m⁻³ h⁻¹ (day) to 5355.33 ± 420.37 ng m⁻³ h⁻¹ (night), marking a 3.7-fold increase. Snowfall dramatically elevated terpenoid concentrations (pre-snowfall: 158.58 ± 14.12 ng m⁻³; post-snowfall: 1080.57 ± 57.76 ng m⁻³) and emission rates (pre-snowfall: 52.86 ± 4.71 ng m⁻³ h⁻¹; post-snowfall: 360.19 ± 19.25 ng m⁻³ h⁻¹), reflecting a 6.8-fold surge. This study underscores the profound influence of light intensity, seasonal shifts, and climatic conditions on airborne phytoncide levels, offering a scientific foundation for optimizing forest therapy and ecotourism strategies.

Urban forests are highly multifunctional and provide numerous ecological functions. Plant functional traits individually or jointly influence the ecological multifunctionality of tree species (TS-EMF) and can also modify TS-EMF in response to environmental changes. However, there has been limited exploration of multitrait combinations for predicting TS-EMF across seasons and of trait thresholds that enhance TS-EMF. Here, for 10 dominant tree species in urban forests of Northeast China, 14 traits were measured and four aboveground and three belowground ecological functions assessed in three seasons. Ecological functions and TS-EMF differed significantly throughout the seasons (P < 0.05). Synergistic relationships were found between carbon sequestration and oxygen release, between cooling and humidification, and between organic carbon accumulation and nutrient cycling. Notably, aboveground multifunctionality played a leading role in TS-EMF. With seasonal changes, resource allocation shifted toward traits related to resource acquisition rather than conservation to maintain TS-EMF. The combination of traits that predicted TS-EMF varied by type, accounting for up to 66.45% of the variation. TS-EMF was primarily driven by leaf structure in spring and by nutrient accumulation in autumn. Leaf carbon content (LCC) consistently served as a stabilizing factor for predicting TS-EMF across seasons. At 36.5–36.8 mg g^–1, LCC had its optimal effect on TS-EMF. Other traits in combination that positively influence total TS-EMF include leaf nitrogen content (3.43–3.45 mg g^–1), leaf phosphorus content (0.80–0.83 mg g^–1), and leaf area (65.86–68.43 cm²). Within these specified trait thresholds, Morus alba and Quercus mongolica were identified as key species. These findings suggest that the trade-off between various ecological functions can be managed by altering plant traits across seasons. This approach could provide a theoretical foundation for enhancing the TS-EMF of urban forests through trait-based management, offering practical guidance for selecting tree species.

Non-structural carbohydrates (NSCs) are critical for plant drought adaptation, but their environmental drivers under prolonged drought remains unclear. We investigated seasonal NSCs dynamics in the leaf, stem and root of Picea crassifolia (Qinghai spruce) during the growing seasons of 2021−2023 under intensifying drought at three altitudes in Qilian Mountains, Northwest China. Our results revealed synchronous seasonal patterns in soluble sugar, starch, and total non-structural carbohydrate within the same year, contrasting with marked altitudinal disparities. As drought progressed (from 2021 to 2023), soluble sugars initially increased (2022) then declined (2023), while starch showed consistent reduction (except leaves). Moreover, the altitude of peak NSCs concentrations shifted from 3200 m in 2021 to 2700 m in 2023. In particular, prolonged drought alters the environmental factors affecting NSCs. NSCs demonstrated significant positive correlations with soil temperature during humid 2021, then negatively with air temperature, vapor pressure deficit, and precipitation during 2022’s initial drought, whereas under 2023’s persistent drought conditions, soil temperature and water content emerged as dominant drivers. Concurrently, the ratio of soluble sugar to starch transitioned from air temperature and precipitation associations (2021−2022) to soil parameter dependence in 2023. These findings provide new insights into the seasonal carbon dynamics of Qinghai spruce and the environmental response mechanisms under increasing drought stress, contributing to a better understanding of tree physiological adaptations in drought stress.

Cryptorhynchus lapathi L., a globally distributed wood-boring pest, significantly threatens poplar (Populus spp.) and willow (Salix spp.) trees. Entomopathogenic fungi (EPFs), particularly Beauveria bassiana (Bals.-Criv.) Vuilla, play a crucial role in integrated pest management because of their broad-spectrum insecticidal properties. This study clarifies the pathogenic mechanisms of B. bassiana CFCC81428 treatment and its oil-based formulation against male and female C. lapathi adults, alongside their impacts on cumulative mortality, enzyme activity and nutrient metabolism. The results indicated that the oil-based formulation significantly enhanced B. bassiana pathogenicity, achieving cumulative mortality rates of 91.7% and 83.8% for male and female adults, respectively, with LT₅₀ values of 7.9 and 8.7 d, markedly outperforming the B. bassiana treatment. Scanning electron microscopy revealed that the oil-based formulation improved spore adhesion to the insects’ cuticle, accelerated spore germination and hyphal growth, and significantly improved cuticular penetration efficiency. Within the host, the activities of detoxification enzymes (GST and CarE) were upregulated, whereas the activities of catalase and peroxidase enzymes were suppressed. Superoxide dismutase activity remained elevated throughout most of the observation time points. Polyphenol oxidase activity significantly increased between 24 and 120 h postinfection, indicating its critical role in preventing B. bassiana invasion. The infection also triggered substantial shifts in the host’s nutrient metabolism, with time-dependent changes observed in carbohydrates, free fatty acids, and soluble proteins. The oil-based formulation exacerbated the depletion of these nutrients, ultimately leading to metabolic collapse. This study indicates that the oil-based formulation optimizes spore germination conditions and accelerates infection, thereby significantly increasing B. bassiana pathogenicity in C. lapathi males, whereas female adults exhibited stronger physiological and metabolic responses, providing new insights for the application of B. bassiana in the biological control of pests.

Allometric equations are fundamental tools in ecological research and forestry management, widely used for estimating above-ground biomass and production, serving as the core foundations of dynamic vegetation models. Using global datasets from Tallo (a tree allometry and crown architecture database encompassing thousands of species) and TRY (a plant traits database), we fit Bayesian hierarchical models with three alternative functional forms (power-law, generalized Michaelis–Menten (gMM), and Weibull) to characterize how diameter at breast height (DBH), tree height (H), and crown radius (CR) scale with and without wood density as a species-level predictor. Our analysis revealed that the saturating Weibull function best captured the relationship between tree height and DBH in both functional groups, whereas the CR–DBH relationship was best predicted by a power-law function in angiosperms and by the gMM function in gymnosperms. Although including wood density did not significantly improve predictive performance, it revealed important ecological trade-offs: lighter-wood angiosperms achieve taller mature heights more rapidly, and denser wood promotes wider crown expansion across clades. We also found that accurately estimating DBH required considering both height and crown size, highlighting how these variables together distinguish trees of similar height but differing trunk diameters. Our results emphasize the importance of applying saturating functions for large trees to improve forest biomass estimates and show that wood density, though not always predictive at broad scales, helps illuminate the biomechanical and ecological constraints underlying diverse tree architectures. These findings offer practical pathways for integrating height- and crown-based metrics into existing carbon monitoring programs worldwide.

Frequent droughts pose considerable threat to global forest carbon uptake, but little is known about the response of forest carbon fluxes in climatic transition zones to seasonal drought. In this study, the responses of carbon fluxes to seasonal drought in two natural forests (Quercus aliena var. acute serrata Maxim and Pinus tabuliformis Carr.) in the Baotianman Nature Reserve were investigated. The Q. aliena forest exhibited a high resilience with stable gross primary productivity (GPP). However, ecosystem respiration (Re) significantly declined by 18.4% compared with normal years, leading to an increase in net carbon sequestration capacity of 4.1%. This resilience was attributed to its deep root system accessing soil water (SWC_50cm) to sustain stomatal openness, coupled with the efficient utilization of photosynthetically active radiation to drive photosynthesis. In contrast, the P. tabuliformis forest, which relied on shallow soil moisture (SWC_20cm), experienced simultaneous decreases in both GPP and Re during drought, with a sharply greater decrease in GPP, resulting in low net carbon sink capacity. Further analysis revealed that the Q. aliena forest prioritized carbon assimilation through a deep water-stomatal synergy strategy (anisohydric behavior), whereas the P. tabuliformis forest adopted an isohydric strategy favoring water conservation at the expense of carbon fixation efficiency. These findings highlight distinct mechanisms underlying drought adaptation between forest types, providing critical insight into optimizing forest carbon cycle models and selecting drought-resistant species under the influence of climate change.

Tree plantations are globally significant, and therefore, growth-related challenges cannot be ignored. Canopy structure and light environment influence the growth of plantations, but the precise relationship remains unclear. We selected seven-year-old poplar plantations of varying cultivars planted various densities and measured their growth, canopy structure, and light environment. The findings indicate that poplar plantations of different cultivars and at different planting densities showed variations in leaf area index (LAI), average leaf angle (ALA), crown length (CL), length ratio (CLR), roundness (CR) and surface area (CSA), which directly or indirectly affect growth, resulting in disparities in their growing conditions. Crown roundness directly impacted growth, while LAI, CLR and ALA influenced growth indirectly by affecting intercellular carbon dioxide concentration. LAI and CLR had a positive effect; ALA had a negative one. Crown length and surface area directly and indirectly influenced growth by affecting photosynthetically active radiation and net photosynthetic rate, with direct impacts being more pronounced. This research has clarified the regulatory role of canopy structure in plantations growth, providing valuable insights for developing more effective management strategies.

Drought influences carbon fixation by plants. Therefore, elucidating its impact on carbon fluxes in plants at the ecosystem level is crucial for assessing their role in mitigating climate change. Using carbon fluxes and environmental factor data from FLUXNET sites, we analyzed the influence of drought on carbon fluxes, their drivers, time-lag effects, and recovery times across various climatic regions and seasons. Results showed drought significantly decreased gross primary production (GPP), ecosystem respiration, and net ecosystem productivity in arid regions but slightly increased carbon sequestration in humid regions. Summer droughts negatively affected vegetation carbon fluxes, partly offset by the positive impact of spring droughts. Nonforest carbon fluxes were more susceptible to drought effects than forest fluxes. Soil water content (SWC) was the main influence on changes in arid regions, whereas vapor pressure deficit (VPD) dominated humid regions. Decreased SWC and increased VPD reduced carbon sequestration in arid regions but increased it in humid regions. Increased VPD reduced GPP, leading to forest carbon loss, whereas decreased SWC reduced GPP, leading to nonforest carbon loss. The lag time of the drought effects on carbon fluxes was longer in humid regions (19.44 d) than in arid regions (14.71 d). Compared to nonforest areas (16.74 d and 57 d for drought lag and recovery time, respectively), forest areas had a longer lag (18.81 d) and recovery time (92 d). The findings revealed discrepancies in the main factors regulating vegetation carbon fluxes during droughts between arid and humid regions and between forest and nonforest ecosystems. These insights provide a new perspective on understanding and simulating carbon–climate feedback. Enhancing ecosystem diversity is a feasible measure to increase drought resistance.

Peri-urban plantations in the Mediterranean are often degraded due to human inactivity and climate change, leading to a loss of ecosystem services and biodiversity. This study investigates the impact of different thinning practices on carbon sequestration and tree stability in a degraded peri-urban plantation in the Italian Apennines, six years after thinning. Three treatments were compared: (a) moderate thinning from below (− 25% biomass), representing the typical practice; (b) intense selective thinning (-35% biomass), representing an innovative approach; and (c) no management as the control. Growth projections were used to estimate carbon recovery for these treatments, based on site-specific models calibrated with real data. The results show that both thinning approaches increased carbon sequestration over time, with the innovative thinning achieving a 7% higher annual carbon sequestration rate than traditional thinning and 8% more than the control. Estimated payback times were 9 years for recovering the harvested volume in both thinning approaches, 10 years for innovative thinning to surpass traditional thinning, 17 years for innovative thinning to surpass the control, and 24 years for traditional thinning to surpass the control. Additionally, tree mechanical stability improved significantly in both thinning treatments after two years, with further increases observed in the innovative thinning group after six years. These results suggest that selective thinning can accelerate forest recovery and carbon sequestration, especially in areas with high stem density, where it can reduce the negative impacts of tree mortality and deadwood accumulation. However, careful planning is required to mitigate potential short-term stability issues, particularly in challenging environments (e.g., windy conditions, steep slopes). Forest management strategies should therefore aim to balance growth, carbon storage, and tree stability, considering both long-term sustainability and local environmental conditions. The findings are particularly relevant for current climate change mitigation strategies, emphasizing that thinning should be carefully tailored to forest type and conditions to maximize benefits in carbon credit generation and sustainable forest management practices.

The latitudinal diversity gradient (LDG) is one of the most notable biodiversity patterns in biogeography. The metabolic theory of ecology (MTE) explains ecological patterns, including the LDG. However, little is known about whether the LDG remains stable over time as climate warming progresses and whether MTE remains applicable to clarify this pattern. In this study, forest data spanning temperate, subtropical, and tropical zones across China were used to analyze long-term changes in the LDG of tree species over 2005–2020. Based on the MTE framework, spatial scales were considered to assess temperature dependence of typical forest trees species. Our results show that species richness decreased with increasing latitude, and that temperature was the primary driver of this change. Although temperature in China has significantly increased over the past two decades, the LDG of tree species has remained stable. However, there was a decrease in species richness in tropical regions over time. With predictions of the MTE, the logarithm of typical forest tree species richness exhibited negative linear relationships with the inverse of ambient temperature, indicating temperature dependence of species richness. However, the relationship remained stable and was strongly influenced by spatial scale, intensifying as spatial scale increased. The findings emphasize the important role of temperature in shaping the LDG. The effects of spatial scale, in particular, should be considered when biodiversity management plans are developed for future climate change.

The formation of wood is affected by the growing season and the environment. Ring-porous tree species have distinct earlywood-latewood differences. However, it is not clear how earlywood and latewood respond to drought and the differences in adaptation. Therefore, based on the analyses of phenology, growth, and xylem development over a year, xylem development in Fraxinus mandshurica was divided into earlywood, transition, and latewood stages. Variation patterns of 38 wood indices from 31 genotypes indicated that the formation of wood tissues was inhibited, and the proportion of xylem cells was affected by drought at each stage. However, soluble sugar affected osmotic regulation only during drought across earlywood and transition stages. To maintain water and nutrient transport during drought and to resist embolism risk, drought in the earlywood stage leads to varying degrees of earlywood vessel diameter reduction, with pits enlarging to compensate. In contrast, during the latewood stage, drought causes latewood vessel diameter to increase and pits to shrink accordingly. In addition, the results indicate that several wood indices correlate with drought resistance at each stage, but earlywood vessel diameter, soluble sugar, and latewood vessel diameters exhibited the strongest correlations in the earlywood, transition, and latewood stages. These findings provide clues to understanding plant survival strategies under drought stress and are of significance for plant ecology research on the growth and adaptation of tree species under climate change.

Evaluating the effectiveness of forest restoration projects is crucial for designing adaptive restoration strategies. However, existing studies have primarily focused on ecological outcomes while overlooking cost inputs. This gap can lead to increased uncertainties in restoration planning. Here we investigated forest dynamics in China’s Upper Yangtze River Basin (UYRB) using kernel Normalized Difference Vegetation Index (kNDVI), Leaf Area Index (LAI), Gross Primary Productivity (GPP), Ku-band Vegetation Optical Depth (Ku-VOD) time series and climate data from 1982 to 2020. Subsequently, we employed a residual trend analysis integrating temporal effects to determine the relative contributions of climate change and human activities to forest dynamics before and after the implementation of forest restoration engineering in 1998. Additionally, we developed an Afforestation Efficiency Index (AEI) to quantitatively assess the cost efficiency of afforestation projects. Results indicated that forest in the UYRB showed sustained increases during 1982–2020, with most areas experiencing greater growth after 1998 than before. Temporal effects of climatic factors influenced over 42.7% of the forest, and incorporating time-lag and cumulative effects enhanced climate-based explanations of forest variations by 1.61–24.73%. Human activities emerged as the dominant driver of forest dynamics post 1998, whereas climate variables predominated before this period. The cost-effectiveness of forest restoration projects in the UYRB typically ranges from moderate to high, with higher success predominantly observed in the northeastern and eastern counties, while the central, western, and northwestern counties mainly showed relatively low efficiency. These findings stress the need for assessing forest restoration outcomes from both ecological and cost perspectives, and can offer valuable insights for optimizing the layout of forest restoration initiatives in the UYRB.

Soil fertility and forest structure influence tree carbon stocks. However, it remains unclear how tree mycorrhizal types affect these relationships. This study addressed the question of how aboveground and belowground tree carbon stocks in soils with different mycorrhizal types are affected by soil fertility and forest structure. Tree demographic data were used from a 21.12-ha study area collected over a ten-year period (2009–2019), covering 43 species of woody plants and more than 50,000 individuals. Relationships between tree carbon stock, soil fertility and forest structure (stand density, diameter variation, species diversity and spatial distribution) were examined, as well as whether these relationships differed between arbuscular mycorrhiza and ectomycorrhizal mycorrhiza groups in a typical temperate conifer and broad-leaved mixed forest. We found that total tree carbon stock was positively impacted by variations in stand density and tree diameter but negatively influenced by soil fertility, tree species diversity and uniform angle index. Soil fertility promoted carbon stock of trees associated with arbuscular mycorrhiza (AM) but inhibited the carbon stock of trees with ectomycorrhizal mycorrhiza fungi (EcM). Carbon stock of AM trees was mainly influenced by soil fertility, while carbon stock of EcM trees was influenced by stand density. Our findings show that mycorrhizae types mediate the impact of stand structure and soil fertility on tree carbon stocks and provides new evidence on how forest tree carbon stocks may be enhanced based on the types of mycorrhizal associations. Tree species with different mycorrhizal types can be managed in different ways.

Desert shrubs are indispensable in maintaining ecological stability by reducing soil erosion, enhancing water retention, and boosting soil fertility, which are critical factors in mitigating desertification processes. Due to the complex topography, variable climate, and challenges in field surveys in desert regions, this paper proposes YOLO-Desert-Shrub (YOLO-DS), a detection method for identifying desert shrubs in UAV remote sensing images based on an enhanced YOLOv8n framework. This method accurately identifying shrub species, locations, and coverage. To address the issue of small individual plants dominating the dataset, the SPDconv convolution module is introduced in the Backbone and Neck layers of the YOLOv8n model, replacing conventional convolutions. This structural optimization mitigates information degradation in fine-grained data while strengthening discriminative feature capture across spatial scales within desert shrub datasets. Furthermore, a structured state-space model is integrated into the main network, and the MambaLayer is designed to dynamically extract and refine shrub-specific features from remote sensing images, effectively filtering out background noise and irrelevant interference to enhance feature representation. Benchmark evaluations reveal the YOLO-DS framework attains 79.56% mAP40weight, demonstrating 2.2% absolute gain versus the baseline YOLOv8n architecture, with statistically significant advantages over contemporary detectors in cross-validation trials. The predicted plant coverage exhibits strong consistency with manually measured coverage, with a coefficient of determination (R²) of 0.9148 and a Root Mean Square Error (RMSE) of 1.8266%. The proposed UAV-based remote sensing method utilizing the YOLO-DS effectively identify and locate desert shrubs, monitor canopy sizes and distribution, and provide technical support for automated desert shrub monitoring.

The rise in urbanization has increasingly restricted access to natural environments, posing substantial risks to the physical and mental health of urban populations, including university students and other high-stress groups. This study examines the comparative effects of outdoor forest meditation (OFM) and indoor nature meditation (INM) in simulated nature environments (SNEs) on the physiological and psychological health of university students. A pretest–posttest repeated measures design was employed, with 40 students participating in three replicated OFM sessions and three identical INM sessions across varied SNE settings. Key physiological metrics, including heart rate (HR), blood pressure (BP), and salivary amylase concentration (SAC), were measured before and after each session. Psychological well-being was assessed using the Perceived Stress Scale-10 (PSS-10) and Profile of Mood States (POMS). Results revealed significant reductions (p < 0.05) in most post-intervention outcomes, except in the second indoor session across physiological and psychological responses, while multi-sensory INM sessions produced comparable benefits. Notably, SNEs with enhanced sensory components were effective, though slightly less impactful than OFM. These findings suggest that both OFM in nature and INM in SNEs can benefit university students’ well-being. INM in SNEs offers a promising alternative for those with limited access to natural settings, contributing meaningfully to stress reduction and overall well-being. This study highlights the potential for nature-based strategies for human health in urban centres, advocating for further investigation into the long-term impacts of SNEs and optimal sensory configurations for maximizing therapeutic effects in urban populations.

We investigated the impact of convexity and isoperimetric deficits on the accuracy of sectional area estimates of tree stems using traditional methods (caliper, tape, formulas based on stem diameter and circumference). In two complementary experiments, the use of photographs to estimate cross-sectional areas was first validated, then the use of a caliper and diameter tape was computer-simulated. The results indicated that the photographic method offers high precision, with mean relative errors below 0.1%, minimal deviation, and no significant bias, and the traditional methods led to substantial and systematic errors, with deviations from circularity and convexity significantly increasing the errors in area estimation.