Are you a student at a higher institution or a graduate who has published his/her first paper in the Journal of Forestry Research or another legitimate scientific journal? If yes, this paper is written specifically for you since you may soon start receiving invitations to act as a referee. If you are an early career reviewer, you may still find this paper enlightening. Based on his experience, a senior editor summarizes some critical information that, in his view, you may need to know. He provides nine main suggestions to have on your radar, and discusses what you should do or not do as a peer reviewer.

This paper addresses the final stage of the study concerning the practical use of the best Russian methods, technologies and means for detecting and extinguishing forest fires in Russia. In general, the work is aimed at increasing the effectiveness of the forest fire protection system by improving the methodological and technical support for the use of the best new innovations. In the course of the study, analytical methods have been applied, tested and used in silviculture, while developing and improving the regulatory legal and methodological frameworks. Based on the selection of research directions in the preliminary stages of work, analysis of the current state, use, and the development forecast of the most effective and promising technologies was carried out. In addition, for detecting, controlling and extinguishing forest fires, including a comparative analysis of their economic efficiency, methods for practical use of the best Russian innovations was developed. A significant number of new developments have accumulated which, for a number of reasons, have not been implemented. Taking into account the current state and dynamics of these promising methods, technologies, means of detecting and extinguishing forest fires, this study substantiates the development forecast of these promising innovations and their content. Its structure includes general provisions, concepts and terminology, regulatory support, the procedure for assessing the feasibility and effectiveness of the innovations, as well as a list of recommended documents for studying the use of technology for detecting, controlling and extinguishing forest fires. These methods will help meet modern requirements for the protection of forests from wildfires, and present an algorithm for their implementation in practice.

Two systems of additive equations were developed to predict aboveground stand level biomass in log products and harvest residue from routinely measured or predicted stand variables for Pinus radiata plantations in New South Wales, Australia. These plantations were managed under three thinning regimes or stand types before clear-felling at rotation age by cut-to-length harvesters to produce sawlogs and pulpwood. The residue material following a clear-fell operation mainly consisted of stumps, branches and treetops, short off-cut and waste sections due to stem deformity, defects, damage and breakage. One system of equations did not include dummy variables for stand types in the model specification and was intended for more general use in plantations where stand density management regimes were not the same as the stand types in our study. The other system that incorporated dummy variables was for stand type-specific applications. Both systems of equations were estimated using 61 plot-based estimates of biomass in commercial logs and residue components that were derived from systems of equations developed in situ for predicting the product and residue biomass of individual trees. To cater for all practical applications, two sets of parameters were estimated for each system of equations for predicting component and total aboveground stand biomass in fresh and dry weight respectively. The two sets of parameters for the system of equations without dummy variables were jointly estimated to improve statistical efficiency in parameter estimation. The predictive performances of the two systems of equations were benchmarked through a leave-one-plot-out cross validation procedure. They were generally superior to the performance of an alternative two-stage approach that combined an additive system for major components with an allocative system for sub-components. As using forest harvest residue biomass for bioenergy has increasingly become an integrated part of forestry, reliable estimates of product and residue biomass will assist harvest and management planning for clear-fell operations that integrate cut-to-length log production with residue harvesting.

Mulberry is economically important and can also play a pivotal role in mitigating greenhouse gases. Leaf and shoot traits were measured for Morus alba var. Kanmasi, M. alba var. Karyansuban, M. alba var. Latifolia, and M. alba var. PFI-1 to assess aboveground biomass (AGB) and carbon sequestration. Variety-specific and multivariety allometric AGB models were developed using the equivalent diameter at breast height (EDBH) and plant height (H). The complete-harvest method was used to measure leaf and shoot traits and biomass, and the ash method was used to measure organic carbon content. The results showed significant (p < 0.01) varietal differences in leaf and shoot traits, AGB and carbon sequestration. PFI-1 variety had the greatest leaf density (mean ± SE: 1828.3 ± 0.3 leaves tree⁻¹), Karyansuban had the largest mean leaf area (185.94 ± 8.95 cm²). A diminishing return was found between leaf area and leaf density. Latifolia had the highest shoot density per tree (46.6 ± 1.83 shoots tree⁻¹), total shoot length (264.1 ± 2.32 m), dry biomass (16.69 ± 0.58 kg tree⁻¹), carbon sequestration (9.99 ± 0.32 kg tree⁻¹) and CO₂ mitigation (36.67 ± 1.16 kg). The variety-specific AGB models b(EDBH) and b(EDBH)² showed good fit and reasonable accuracy with a coefficient of determination (R ²) = 0.98–0.99, standard error of estimates (SEE) = 0.1125–0.3130 and root mean square error (RMSE) = 0.1084–0.3017. The multivariety models bln(EDBH) and (EDBH)^0.756 showed good-fitness and accuracy with R ² = 0.85–0.86, SEE = 1.6231–1.6445 and RMSE = 1.609–1.630. On the basis of these findings, variety Latifolia has good potential for biomass production, and allometric equations based on EDBH can be used to estimate AGB with a reasonable accuracy.

Although the scientific knowledge about some associations between physical parameters of the soil is consolidated, studies focused on investigating the dynamics of forest restoration processes and the structure of soils remain incipient. The study area is located in Cerrado and is called as Private Natural Heritage Reserve (RPPN) Águas Perenes Forest (perennial water forest) and was selected as a “High Conservation Value Forest”, provides scope to investigate the soil physical properties recovery on passive restoration sites, with different ages but with the same land use history. So, the aim was to investigate the soil density, moisture, penetration resistance and infiltration rate with long-term from old (FA, 46 year-old), medium (FB, 11 year-old) and young (FC, 8 year-old) passive restoration sites. It was observed differences in soil density, as well as in soil moisture, resistance to penetration and infiltration rate. Mean densities recorded for FA, FB and FC were 1.38, 1.48 and 1.53 g cm⁻³, respectively. FA recorded higher mean soil moisture (14.9%) than FB (11.5%) and FC (10.0%), whereas mean soil resistance to penetration was increased from FA (0.87 MPa) to FB (0.91 MPa) and FC (1.10 MPa). The average infiltration rate was almost similar in FA and FB (FA = 76.43 mm h⁻¹; FB = 77.48 mm h⁻¹) and approximately 39% higher than FC (55.79 mm h⁻¹). Thus, although soil density and moisture were different in each passive restoration site, 11 year-old passive restoration site showed similar resistance to penetration and infiltration rate to the old (46 years) passive restoration site. These features allowed seeing improvements in hydrological maintenance in the soil and revealed that passive restoration in Cerrado is able to improve the physical features on a soil presenting similar texture, climate and management history.

As forests in neotropical regions, particularly in developing countries, are devastated, interventions to restore biodiversity and its ecological functions are needed. Rural producers have thus been encouraged to grow trees for wood production as an economic activity. The objective of this study was to quantify the increment of wood density of four forest species from different successional classes of a mixed system of restoration in a neotropical forest in Brazil. Tree discs were sampled at breast height and analyzed radially by X-ray densitometry to obtain apparent density and basic density. Three trees each of a species from the pioneer, early and late secondary successional stages and of the dominant species in the climax community. The radial profiles indicated increasing density from the pith to bark of trunks, except for some variations due to wood defects and growth. Average density was 0.576 g cm⁻³, 0.655 g cm⁻³, 0.706 g cm⁻³ and 0.775 g cm⁻³, respectively, for Peltophorum dubium, Schinus terebinthifolius, Cariniana estrellensis and Hymenaea courbaril. Radial profiles indicated higher amplitudes in the apparent densities for slow-growing species. X-ray densitometry generated parameters such as minimum, average and maximum densities, and radial density variations. These parameters are important for understanding the ecological functional role of successional classes of the Atlantic Forest from the Neotropical region.

The stoichiometry of carbon, nitrogen and phosphorous in plants can reflect the interactions between plants and their environment. The interplay between plant nutrients, climatic factors, and soil properties and the underlying regulatory mechanisms are pillars of ecology but remain underexplored. In this study of plant C–N–P stoichiometry and nutrient resorption in Castanopsis hystrix groves in three cities (Guangzhou, Zhongshan, and Lechang) that represent an urban–rural gradient in Guangdong Province, South China, we explored potential relationships among NO₂ concentrations, diameter at breast height (DBH), and resident human population. Mean annual temperature, mean annual precipitation, insolation duration per year, and the human resident population differed significantly among the three cities. Soil C-N-P was always highest in suburban Lechang, and the concentration of NO₂ was highest in urban Guanghzou (55.33 ± 0.67 μg m^–3) and positively correlated with the resident population and leaf N:P. Our findings suggest that C–N–P stoichiometry of C. hystrix was better explained by NO₂ than by soil C–N–P stoichiometry and that nutrient resorption was better explained by leaf nutrients and DBH than by NO₂ and soil stoichiometry. Our study supports the hypothesis that rapid urbanization influences NO₂ concentrations and microclimate, which may jointly change the stoichiometry of plant nutrients in the forest ecosystems.

Ecological stoichiometry provides a framework for the balance and flow of elements between organisms and ecosystems. Elemental phenotypes have an important influence on the environmental adaptation and ecological evolution of plants. There have been few reports on inter- and intra-specific phenotypic variations of ecological stoichiometric traits for congeneric species in a mixed forest although such variations are well- documented at the species level at global, regional and local scales. In this study, total carbon (TC), nitrogen (TN), phosphorus (TP) and potassium (TK) were measured in leaves and the elemental phenotypes were statistically analyzed in four species of oaks—Quercus fabri, Q. serrata var. glandulifera, Q. acutissima and Q. variabilis—in a mixed-oak secondary forest in Yushan, Jiangsu, China. The average element concentrations in the four oak species were not relatively higher than previously reported for oaks from world and Chinese flora. Ecological stoichiometry traits were correlated with tree height and diameter at breast height, indicating that phosphorous and potassium were positively correlated with tree size, while carbon was negatively correlated, especially the relationship between oak growth and total carbon or total phosphorus was obvious, and the study concluded that this was because plant growth depended on phosphorus storage and had opposite effects on leaf carbon accumulation. Based on tree plasticity index and the coefficient of variation, there was medium variation in element concentrations. The plasticity index of total carbon levels was the lowest, and that of potassium the highest. Principal component analysis and cluster analysis showed that the intra-specific variation among the four oak species was higher than inter-specific variation. From the perspective of nutrient supply and ecological adaptation, this study creates a foundation for the management of secondary oak forest stands.

Forests in the aridlands of Sudan are distinctive in nature and require special attention due to the great role they play as a first and last line of defense against southward desertification. Thus, to determine their conservative and protective needs based on current conditions in the Wad Al-Bashir Forest (WF), toward ensuring sustainable forest resources in these areas, we used a systematic field survey, existing and available documents review and key informant interviews (KII), to collect data from 08 December 2017 to 15 May 2018. A severe depletion and changes in the forest tree cover and composition were found during the field survey, where species such as Balanitis aegyptiaca is threatened and invasive species (e.g., Acacia nubica) have started to dominate. Reviewed documents have credited illegal cutting and agricultural activities for the changes in the forest status, whereas the KII indicated that past and current forest conservative and protective practices (CPPs), where forest clearance for agricultural, grazing, pests and disease control, were not given a deserved consideration as they relate to tree cutting and reforestation practices. Likewise, negligence of the needs of those who depend on the forest and inadequate funds have constrained implementation of some CPPs. Accordingly, on the basis of the results of this study, we recommend that CPPs associated with agriculture, grazing, forest fire, pest and disease control should be a top priority concern of forest authorities. Better financial support, which could be enriched by involving governmental and non-governmental organizations, is also needed to boost CPPs in the WF. Invasive species also need to be cleared and replaced by trees such as A. senegal and B. aegyptiaca that are of economic and environmental value.

Erythrophleum fordii Oliv. (Caesalpiniaceae) is a rosewood species naturally distributed in southeast Asia and south China, and the heartwood is commonly used for high-quality crafts and furniture. While there are differences in heartwood development among single trees with distinct social status, the relationship between heartwood development and growth performance remains unclear. This information is essential to improve plantation management for high-yield heartwood production. Forty dominant, intermediate and suppressed trees were sampled from E. fordii plantations aged in 32–35 years in Pingxiang City, Guangxi, China. Stem analysis was carried out to determine horizontal and vertical variations of heartwood and sapwood. Number of annual rings, diameter and area of heartwood and sapwood as well as ratios of heartwood diameter and area at breast height were all significantly influenced by the social status of trees in stands (P < 0.05). In these mid-aged plantations, E. fordii stems developed heartwood once the xylem diameter reached 5–10 cm, and then heartwood diameter and area increased with increasing xylem diameter. Heartwood ring numbers, diameter and area as well as their ratios decreased with increasing height, while sapwood ring numbers and diameter were relatively constant within the section where heartwood occurred. Heartwood and sapwood diameters were equal at heights of approximately 6-m for dominant, 5-m for intermediate and 3-m for suppressed trees. Dominant trees differed considerably from intermediate and suppressed trees in heartwood volume, while heartwood volume ratios were all below 30%, and near 90% in the stem section below 8-m height regardless of social status. Relationship analysis showed that DBH was the most important factor influencing heartwood in even-aged stands. The findings provide evidence for crop tree selection, thinning regimes and reasonable management of plantations of E. fordii.

A Norton-Rice distribution (NRD) is a versatile, flexible distribution for k ordered distances from a random location to the k nearest objects. In a context of plotless density estimation (PDE) with n randomly chosen sample locations, and distances measured to the k = 6 nearest objects, the NRD provided a good fit to distance data from seven populations with a census of forest tree stem locations. More importantly, the three parameters of a NRD followed a simple trend with the order (1, …, 6) of observed distances. The trend is quantified and exploited in a proposed new PDE through a joint maximum likelihood estimation of the NRD parameters expressed as a functions of distance order. In simulated probability sampling from the seven populations, the proposed PDE had the lowest overall bias with a good performance potential when compared to three alternative PDEs. However, absolute bias increased by 0.8 percentage points when sample size decreased from 20 to 10. In terms of root mean squared error (RMSE), the new proposed estimator was at par with an estimator published in Ecology when this study was wrapping up, but otherwise superior to the remaining two investigated PDEs. Coverage of nominal 95% confidence intervals averaged 0.94 for the new proposed estimators and 0.90, 0.96, and 0.90 for the comparison PDEs. Despite tangible improvements in PDEs over the last decades, a globally least biased PDE remains elusive.

Forest resource management and ecological assessment have been recently supported by emerging technologies. Terrestrial laser scanning (TLS) is one that can be quickly and accurately used to obtain three-dimensional forest information, and create good representations of forest vertical structure. TLS data can be exploited for highly significant tasks, particularly the segmentation and information extraction for individual trees. However, the existing single-tree segmentation methods suffer from low segmentation accuracy and poor robustness, and hence do not lead to satisfactory results for natural forests in complex environments. In this paper, we propose a trunk-growth (TG) method for single-tree point-cloud segmentation, and apply this method to the natural forest scenes of Shangri-La City in Northwest Yunnan, China. First, the point normal vector and its Z-axis component are used as trunk-growth constraints. Then, the points surrounding the trunk are searched to account for regrowth. Finally, the nearest distributed branch and leaf points are used to complete the individual tree segmentation. The results show that the TG method can effectively segment individual trees with an average F-score of 0.96. The proposed method applies to many types of trees with various growth shapes, and can effectively identify shrubs and herbs in complex scenes of natural forests. The promising outcomes of the TG method demonstrate the key advantages of combining plant morphology theory and LiDAR technology for advancing and optimizing forestry systems.

Recent applications of digital photogrammetry in forestry have highlighted its utility as a viable mensuration technique. However, in tropical regions little research has been done on the accuracy of this approach for stem volume calculation. In this study, the performance of Structure from Motion photogrammetry for estimating individual tree stem volume in relation to traditional approaches was evaluated. We selected 30 trees from five savanna species growing at the periphery of the W National Park in northern Benin and measured their circumferences at different heights using traditional tape and clinometer. Stem volumes of sample trees were estimated from the measured circumferences using nine volumetric formulae for solids of revolution, including cylinder, cone, paraboloid, neiloid and their respective fustrums. Each tree was photographed and stem volume determined using a taper function derived from tri-dimensional stem models. This reference volume was compared with the results of formulaic estimations. Tree stem profiles were further decomposed into different portions, approximately corresponding to the stump, butt logs and logs, and the suitability of each solid of revolution was assessed for simulating the resulting shapes. Stem volumes calculated using the fustrums of paraboloid and neiloid formulae were the closest to reference volumes with a bias and root mean square error of 8.0% and 24.4%, respectively. Stems closely resembled fustrums of a paraboloid and a neiloid. Individual stem portions assumed different solids as follows: fustrums of paraboloid and neiloid were more prevalent from the stump to breast height, while a paraboloid closely matched stem shapes beyond this point. Therefore, a more accurate stem volumetric estimate was attained when stems were considered as a composite of at least three geometric solids.

To verify if the response by Eucalyptus clones in a single-tree plot is influenced by neighboring plants and to determine the effect of missing and/or dominated plants, seven eucalyptus trials in four Brazilian states were analyzed in a randomized complete block design with one plant/plot and 30 replications. Mean annual increment (MAI, m³ ha⁻¹ per year) was determined for three-year-old clones. The influence of neighboring clones was estimated by a linear regression coefficient between the MAI of each clone/plot and the average of a clonal MAI and its eight neighbors. To determine the effect of missing and/or dominated trees, a correction between the MAI and the area available/plant was applied. Subsequent analysis considered unadjusted and adjusted data for missing and dominated trees. Estimate of accuracy and index of coincidence were used to compare the adjustments. In single-tree plots, clone performances were not influenced by neighboring plants. Experimental accuracy was not increased by any of the adjustments employed and the clone ranking was not altered, and therefore did not justify their use.

Tree mortality models play an important role in predicting tree growth and yield, but existing mortality models for Larix gmelinii subsp. principis-rupprechtii, an important species used for regeneration and afforestation in northern China, have overlooked potential regional influences on tree mortality. This study used data acquired from 102 temporary sample plots (TSPs) in natural stands of Prince Rupprecht larch in the state-owned Guandi Mountain Forest (n = 67) and state-owned Boqiang Forest (n = 35) in northern China. To model stand-level tree mortality, we compared seven model forms of county data. Three continuous (dominant height, plot mean diameter, and basal area per hectare) and one dummy variable with two levels (region) were used as fixed effects variables. Tree morality variations caused by forest blocks were accounted for using forest blocks as a random effect in selected models. Results showed that tree mortality significantly positively correlated with stand basal area and dominant height, but negatively correlated with stand mean diameter. Incorporating both the dummy variables and random effects into the tree mortality models significantly increased the fitting improvements, and Hurdle Poisson mixed-effects model showed the most attractive fit statistics (largest R ² and smallest RMSE) when employing leave-one-out cross-validation. These mixed-effects dummy variable models will be useful for accurately predicting Larix tree mortality in different regions.

Investigating the effects of ontogenetic stage and leaf age on leaf traits is important for understanding the utilization and distribution of resources in the process of plant growth. However, few studies have been conducted to show how traits and trait-trait relationships change across a range of ontogenetic stage and leaf age for evergreen coniferous species. We divided 67 Pinus koraiensis Sieb. et Zucc. of various sizes (0.3–100 cm diameter at breast height, DBH) into four ontogenetic stages, i.e., young trees, middle-aged trees, mature trees and over-mature trees, and measured the leaf mass per area (LMA), leaf dry matter content (LDMC), and mass-based leaf nitrogen content (N) and phosphorus content (P) of each leaf age group for each sampled tree. One-way analysis of variance (ANOVA) was used to describe the variation in leaf traits by ontogenetic stage and leaf age. The standardized major axis method was used to explore the effects of ontogenetic stage and leaf age on trait-trait relationships. We found that LMA and LDMC increased significantly and N and P decreased significantly with increases in the ontogenetic stage and leaf age. Most trait-trait relationships were consistent with the leaf economic spectrum (LES) at a global scale. Among them, leaf N content and LDMC showed a significant negative correlation, leaf N and P contents showed a significant positive correlation, and the absolute value of the slopes of the trait-trait relationships showed a gradually increasing trend with an increasing ontogenetic stage. LMA and LDMC showed a significant positive correlation, and the slopes of the trait-trait relationships showed a gradually decreasing trend with leaf age. Additionally, there were no significant relationships between leaf N content and LMA in most groups, which is contrary to the expectation of the LES. Overall, in the early ontogenetic stages and leaf ages, the leaf traits tend to be related to a "low investment-quick returns" resource strategy. In contrast, in the late ontogenetic stages and leaf ages, they tend to be related to a "high investment-slow returns" resource strategy. Our results reflect the optimal allocation of resources in Pinus koraiensis according to its functional needs during tree and leaf ontogeny.

In scenarios of climatic change when increased global temperatures can be expected, it is essential to search for technologies that favor sapling survival and growth after planting and increase yield in the field. Kaolin-based particle films (KBPF) have been applied as barriers against the deleterious effects of high levels of solar radiation. The objective of the present study was to assess the effects of applying purified calcined kaolin-based particle film to young eucalyptus plants. Five treatments were carried out: 0% (just water), 3%, 5%, 7%, and 10% calcined kaolin applied to the adaxial part of the leaves. A complete randomized block design was used with five treatments and ten replicates. The plants were assessed for height, diameter at ground level, gas exchanges (net photosynthetic CO₂ assimilation, stomatal conductance and transpiration), instantaneous (WUE) and intrinsic water use efficiency (IWUE), chlorophyll a fluorescence (maximum quantum yield of photosystem II (PSII) (F_v/F_m), concentration of active reaction centers in relation to the quantity of photons absorbed (RC/ABS) and the maximum ratio of quantum yields of photochemical and concurrent non-photochemical processes in PSII (F_v/F₀), SPAD reading and leaf ontogeny. The 3% KBPF concentration showed the best responses in biometric assessments 80 days after planting (DAP) and were corroborated by the responses of the leaf, stem and shoot dry matter production as a whole. The leaf ontogeny assessments showed positive responses following KBPF application when considering leaf development, with 7% KBPF concentration resulting in the highest mean values. The mean specific leaf mass had negative response to high KBPF concentrations. At 60 DAP, the gas exchange variables during both assessment periods declined with an increase in KBPF concentration. Significant differences as a result of KBPF applications were found only at the start of the assessments (34 DAP) for both WUE and for IWUE. Leaf ‘greenness’ (SPAD reading) at 47 days showed a quadratic relationship in both periods. The variables of chlorophyll fluorescence showed a linear response at 34 DAP and a quadratic response 60 DAP. KBPF application increased height and diameter growth in plants treated with 3% KBPF but this response was not associated with photochemical efficiency and photosynthetic carbon assimilation values on a single-leaf basis. The best performance among the variables was provided by 3% KBPF application.

To explore the critical relationships of photosynthetic efficiency and stem sap flow to soil moisture, two-year-old poplar saplings were selected and a packaged stem sap flow gauge, based on the stem-heat balance method, and a CIRAS-2 portable photosynthesis system were used. The results show that photosynthetic rates (P _n), transpiration rates (T _r), instantaneous water use efficiency (WUE) and the stem sap flow increased initially and then decreased with decreasing soil water, but their critical values were different. The turning point of relative soil water content (W _r) from stomatal limitation to nonstomatal limitation of P _n was 42%, and the water compensation point of P _n was 13%. Water saturation points of P _n and T _r were 64% and 56%, respectively, and the WUE was 71%. With increasing soil water, the apparent quantum yield (AQY), light saturation point (LSP) and maximum net photosynthetic rate (P _nmax) increased first and then decreased, while the light compensation point (LCP) decreased first and then increased. When W _r was 64%, LCP reached a lower value of 30.7 µmol m⁻² s⁻¹, and AQY a higher value of 0.044, indicating that poplar had a strong ability to utilize weak light. When W _r was 74%, LSP reached its highest point at 1138.3 µmol∙m⁻² s⁻¹, indicating that poplar had the widest light ecological amplitude and the highest light utilization efficiency. Stem sap flow and daily sap flow reached the highest value (1679.7 g d⁻¹) at W _r values of 56% and 64%, respectively, and then declined with increasing or decreasing W _r, indicating that soil moisture significantly affected the transpiration water-consumption of poplar. Soil water was divided into six threshold grades by critical values to maintain photosynthetic efficiency at different levels, and a W _r of 64–71% was classified to be at the level of high productivity and high efficiency. In this range, poplar had high photosynthetic capacity and efficient physiological characteristics for water consumption. The saplings had characteristics of water tolerance and were not drought resistant. Full attention should be given to the soil water environment in the Yellow River Delta when planting Populus.

Plantations have been widely established to improve ecosystem services and functioning. Black locust, Robinia pseudoacacia L. is a common, widely planted species to control soil erosion on the Loess Plateau. Previous studies have focused on economic values but the interactions between soil and plant carbon (C), nitrogen (N) and phosphorus (P) remain unknown. Investigating variations of soil, green and senesced leaf C, N and P levels in R. pseudoacacia along a latitudinal gradient is useful to understanding its ecological functions. The results show that soil C, N and senesced leaf N and P significantly decreased with an increase in latitude, but there were no significant changes in the senesced leaf C and soil P. The resorption efficiency of N was related with latitude and soil N levels, and the relation between green leaf N and soil N was significant. These relations suggest that soil N was the key in affecting green leaf N levels. At higher latitudes, senesced leaves had lower N levels associated with higher N resorption efficiency to maintain a stable N content in green leaves. With a decrease of soil N, R. pseudoacacia can enhance N resorption efficiency to meet the demand of growth. Thus, it is an important species for reforestation, especially in nutrient-poor environments.

Taxol (Paclitaxel), an important anticancer drug, is derived at very low yields from Taxus (yew) species that grow very slowly. In the present study, thirteen genes that encode enzymes involved in Taxol biosynthesis in Taxus spp. were analyzed with bioinformatics methods, and their expression levels in different tissues and after cold and hormone treatments were also analyzed. The results indicated that many cis-elements related to abiotic stresses and hormones were found in the promoter sequences of the 8 genes involved in Taxol biosynthesis. Moreover, the 13 enzymes encoded by the target genes were located in different organelles and had many phosphorylation sites in the response proteins. The 13 genes were expressed highly either in roots or in stems, with lower transcripts in needles, and they were highly expressed after treatment with cold, gibberellin, methyl jasmonate or coronatine, consistent with predictions based on the bioinformatics analysis. These results suggest that the factors such as hormones and abiotic stresses stimulate taxane biosynthesis in yews, providing an important way to sustainably generate taxanes from yew trees or their cell cultures to improve Taxol yields.

Coumarate 3-hydroxylase (C3h) genes participate in the synthesis of lignin and may affect the properties of wood that are important for its commercial value. A better understanding of the natural variation in C3h genes and their associations to wood properties is required to effectively improve wood quality. We used a candidate gene-based association mapping approach to identify CfC3h allelic variants associated with traits that affect the wood properties of Catalpa fargesii. We first isolated the full-length CfC3h cDNA (1825 bp), which was expressed at relatively high levels in xylem according to real time-polymerase chain reaction. In totally, 17 common single-nucleotide polymorphisms (minor allele frequency > 5%) were identified through cloning and sequencing the CfC3h locus from a mapping population (including 88 unrelated natural C. fargesii individuals collected from main distribution area). Nucleotide diversity and linkage disequilibrium (LD) in CfC3h indicate that CfC3h has low nucleotide diversity (π _t = 0.0031 and θ _w = 0.0103) and relatively low LD (within 1800 bp; r ² ≥ 0.1). An association analysis identified eight common single-nucleotide polymorphisms (SNPs) (false discovery rate, Q < 0.10) and ten haplotypes (Q < 0.10) associated with wood properties, explaining 4.92–12.09% of the phenotypic variance in an association population consisted of 125 unrelated natural individuals (The 88 individuals from the mapping population were comprised in the association population). Our study would provide new insight into C3h gene affecting wood quality, and the SNP markers identified would have potential applications in marker-assisted breeding in the future.

Cold-resistance pathways that operate in model plants such as Arabidopsis thaliana and Oryza sativa have been studied extensively. It has been found that CBF genes play an important role in plant cold resistance. Liriodendron chinense, a tree known for its graceful tree shape and widely spread in south China, has weak cold tolerance. However, little is known about its response to cold. To further study the function of L. chinense CBF gene family, we started by characterizing all members of this gene family in the L. chinense genome and their expression profiling. Phylogenetic analysis found that 14 CBF genes in L. chinense are more closely related to their homologues in woody plants and A. thaliana than those in O. sativa. Cis-acting elements and GO analysis showed that some LcCBF genes participated in the biological process of cold stress response. The transcriptomic and RT-qPCR data showed that most of LcCBF genes displayed an initially increasing and subsequently decreasing trend during cold stress course and the expression profile of each member was different. Some LcCBF genes exhibited a different abundance in callus, root, stem and leaf tissues. The structure and expression characteristics of LcCBF genes imply that they may have similar and different functions in response to cold stress conditions. The identification and analysis of LcCBF gene family have laid the foundation for future studies into L. chinense cold stress mechanisms and for the cultivation of cold-resistance cultivars.

Reducing greenhouse gas emissions is one of the major challenges in combating global warming. Carbon, including in the form of carbon dioxide (CO₂), is considered an essential greenhouse gas under human control to demonstrate success in emission reductions. However, many carbon stock quantifications in forest ecosystems still rely on the estimated 50% carbon content instead of more precise species-, tissue- and site-specific values. Thus, this study aimed to thoroughly measure and analyze the carbon content and variability using the 14 major tree species in Northeast China. Over 600 trees were destructively sampled from three different major mountainous regions (i.e., the Changbai, Daxing’an, and Xiaoxing’an mountains), and the carbon contents of each species were precisely measured to the sub-tissue level. Carbon contents varied significantly between species, with foliage carbon mostly found to be the highest, while root carbon contents were the lowest. Average carbon contents can be ranked as: Ulmus laciniata (43.4%) <  Phellodendron amurense (43.5%) <  Acer mono (43.8%) <  Tilia amurensis (44.2%) <  Populus davidiana (44.5%) <  Fraxinus mandshurica (44.7%) <  Juglans mandshurica (44.9%) <  Quercus mongolica (45.3%) <  Betulla davurica (45.8%) <  Betulla platyphylla (46.7%) <  Picea koreansis (46.9%) <  Larix gmelinii (47.4%) <  Pinus koreansis (48.3%) <  Abies nephrolepis (48.3%). Carbon contents were higher in conifers (47.7%) compared to broadleaf species (44.9%). In addition, both tree tissues and growing sites also had a significant effect on carbon content. At the sub-tissue level, only stem’s sub-tissues (i.e., bark, heartwood, and sapwood) carbon contents showed significant variations. The results suggest that bark should be separated from other stem sub-tissues and considered separately when determining carbon stocks. This research contributes to improving estimates of terrestrial carbon quantifications, and in particular, the values obtained can be used in China’s National Forest Inventory.

Silvicultural practices applied in managed forest plantations may help counteract the effects of climate change by influencing soil surface CO₂ efflux (F _s). Understanding the effects of silvicultural practices on F _s will provide unbiased estimates of carbon fluxes and allow better silvicultural decisions for carbon sequestration. Therefore, we assessed how F _s differed seasonally across silvicultural practices (i.e., stocking levels, clone, fertilization and weed control treatments) and evaluated the effects of soil temperature (T _s) and soil volumetric water content (θ _v) on F _s across these practices for a mid-rotation (14 year-old) Pinus radiata plantation in the Canterbury region of New Zealand. There were significant differences in F _s (p < 0.05) over the four seasons, three levels of stocking, and five clones. The effects of fertilization and weed control applied 12 years previously on F _s were insignificant. Annual estimate of F _s (mean ± 1 standard deviation) from the study site was 22.7 ± 7.1 t ha⁻¹ a⁻¹ in the form of CO₂ (6.2 ± 2.1 t ha⁻¹ a⁻¹ in the form of C). F _s values were consistently higher in plots with 1250 stems ha⁻¹ compared to 2500 stems ha⁻¹, which may be related to a strong soil resource limitation because of the close spacing in the latter plantation. Significant differences in F _s across clones suggest that variations in carbon partitioning might explain their growth performance. Silvicultural treatments influenced F _s response to soil temperature (p < 0.05), resulting in models explaining 28–49% of the total variance in F _s. These findings provide insights into how silvicultural management decisions may impact F _s in mid-rotation radiata pine plantations, contributing towards developing more precise and unbiased plantation carbon budgets.

Nitrogen is an essential component in forest ecosystem nutrient cycling. Nitrogen fractions, such as dissolved nitrogen, ammonium, nitrate, and microbial biomass nitrogen, are sensitive indicators of soil nitrogen pools which affect soil fertility and nutrient cycling. However, the responses of nitrogen fractions in forest soils to organic mulching are less well understood. The rhizosphere is an important micro-region that must be considered to better understand element cycling between plants and the soil. A field investigation was carried out on the effect of mulching soil in a 15-year-old Ligustrum lucidum urban plantation. Changes in total nitrogen and nitrogen fractions in rhizosphere and bulk soil in the topsoil (upper 20 cm) and in the subsoil (20–40 cm) were evaluated following different levels of mulching, in addition to nitrogen contents in fine roots, leaves, and organic mulch. The relationships between nitrogen fractions and other measured variables were analysed. Organic mulching had no significant effect on most nitrogen fractions except for the rhizosphere microbial biomass nitrogen (MBN), and the thinnest (5 cm) mulching layer showed greater effects than other treatments. Rhizosphere MBN was more sensitive to mulching compared to bulk soil, and was more affected by soil environmental changes. Season and soil depth had more pronounced effects on nitrogen fractions than mulching. Total nitrogen and dissolved nitrogen were correlated to soil phosphorus, whereas other nitrogen fractions were strongly affected by soil physical properties (temperature, water content, bulk density). Mulching also decreased leaf nitrogen content, which was more related to soil nitrogen fractions (except for MBN) than nitrogen contents in either fine roots or organic mulch. Frequent applications of small quantities of organic mulch contribute to nitrogen transformation and utilization in urban forests.

In the last few decades, the use of environmental radionuclides, particularly caesium-137 (¹³⁷Cs), represented one of the most valid methods for estimating soil erosion. However, the cost associated with the use of the equipment needed for radiometric analyses is still high and, for this reason, finding more easily measurable indicators can be useful. There is a strong correlation between ¹³⁷Cs, organic carbon (OC), nitrogen (N) and water soluble phenols (WSP) exists, indicating the latter parameters as possible early indicators of soil erosion. Based on the above assumptions, the main purpose of this work is to identify specific soil chemical parameters able to indicate early triggering of soil erosion. Specifically, several soil parameters such as pH, electric conductivity (EC), WSP, OC, N and C/N have been evaluated against ¹³⁷Cs and on a comparative basis. In addition, since the rate of soil erosion depends on the degree of coverage and canopy structure, two different tree species (Pinus nigra laricio Poir. and Fagus sylvatica L.) have been considered in this contribution in which ten different scenarios of forest management have been analysed. The results show that the reduction in tree cover of managed sites triggers erosion and nutrient loss processes. It has been observed that the loss of ¹³⁷Cs, compared to the control areas, is closely correlated with those of WSP, OC and N. These parameters (WSP, OC and N), more easily assessable, can be a valid tool to understand easily, triggering of erosive phenomena.

This study explores the effects of vegetation and season on soil microorganisms and enzymatic activity of different wetlands in a temperate climate. Microbial carbon metabolism diversity was assessed using community-level physiological profiles (CLPP) with 31 different carbon substrates. CLPP indicated that significant interactions occur during carbon substrate metabolism of the microorganisms. Furthermore, the different types of vegetation present in the wetland ecosystem combined with the seasonal effects to influence microbial carbon metabolism and enzymatic activity. The most significant differences occurred to carbohydrates, carboxylic acids, and amino acids. The Mantel test confirmed positive correlations between soil enzymatic activities and microbial carbon metabolism. Soil microorganisms in Betula ovalifolia and Carex schmidtii wetlands used carbon substrates more efficiently in summer than those in other forested wetlands during other periods. Enzymatic activities also showed a similar trend as microbial carbon metabolism. The results demonstrate that microbial carbon metabolism patterns can be used as biological indicators in wetland ecological alterations due to vegetation type or to seasonal factors.

In southern China, the eucalyptus plantation industry has been severely restricted by government policy over concerns on negative environmental impacts. In its place, large-scale plantations of high-value tropical tree species such as nitrogen-fixing Dalbergia odorifera and hemiparasite Santalum album have been widely cultivated including in mixed-species plantations. However, despite their poor growth, little information is available on suitable silvicultural practices of these plantations. Therefore, we subjected an 8-year-old mixed stand of D. odorifera and S. album to weeding, fertilization, weeding + fertilization, or no (CK) treatments and measured soil microbial biomass, respiration, nutrients, nitrogen mineralization and leaching and tree growth and litter production. Weeding and fertilization decreased microbial biomass but increased soil respiration, inhibited mineralization, had not effect on leaching of soil nitrogen, and improved the nutrient status of plantation soil. All practices improved the growth of D. odorifera. In the mixed plantation, fertilization increased litter production and nutrient content, but weeding and weeding + fertilization decreased growth of S. album and litter production in mixed plantation because weeding decreased the number of S. album haustoria in underground plant roots. In conclusion, fertilization is recommended; however, weeding-related practices are inappropriate for D. odorifera and S. album mixed plantations. These conclusions have important implications for managing other parasite or mixed-species plantations.

Soil microorganisms and physicochemical properties are considered the two most influencing factors for maintaining plant diversity. However, the operational mechanisms and which factor is the most influential manipulator remain poorly understood. In this study, we examine the collaborative influences of soil physicochemical properties (i.e., soil water, soil organic matter (SOM), salinity, total phosphorus and nitrogen, pH, soil bulk density and fine root biomass) and soil microorganisms (fungi and bacteria) on plant diversity across two types of tree patches dominated by big and small trees (big trees: height ≥ 7 m and DBH ≥ 60 cm; small trees: height ≤ 4.5 m and DBH ≤ 20 cm) in an arid desert region. Tree patch is consists of a single tree or group of trees and their accompanying shrubs and herbs. It was hypothesized that soil physicochemical properties and microorganisms affect plant diversity but their influence differ. The results show that plant and soil microbial diversity increased with increasing distances from big trees. SOM, salinity, fine root biomass, soil water, total phosphorus and total nitrogen contents decreased with increasing distance from big trees, while pH and soil bulk density did not change. Plant and soil microbial diversity were higher in areas close to big trees compared with small trees, whereas soil physicochemical properties were opposite. The average contribution of soil physicochemical properties (12.2%–13.5%) to plant diversity was higher than microbial diversity (4.8%– 6.7%). Salinity had the largest negative affect on plant diversity (24.7%–27.4%). This study suggests that soil fungi constrain plant diversity while bacteria improve it in tree patches. Soil physicochemical properties are the most important factor modulating plant diversity in arid desert tree patches.

The shortage of information regarding the effects of root damage on forest plants, especially trees and shrubs, is the most critical gap in our knowledge of belowground insect herbivory. This study examines how the tea-leaved willow, Salix phylicifolia, responds to simulated root herbivory and how nutrient availability affects these responses. Hydroponically grown cuttings were used to precisely apply the desired levels of root damage. Root: shoot ratios increased proportionally to the intensity of root damage, whereas specific leaf area, leaf water content and chlorophyll fluorescence were not affected. The removal of 2–64% of roots once in early summer and the removal of 25% of roots three times during the summer did not change biomass production by cuttings. The repeated removal of 50 and 75% of roots decreased shoot biomass and, to a lesser extent, total root production. The tolerance of tea-leaved willow to root damage was greater in low nutrient treatment than in high nutrient treatment, thus supporting the Growth Rate Model. According to this model, in low resource conditions plants do not attain their maximum growth rate and therefore have a higher capacity for regrowth after damage. We conclude that, in the absence of water limitations, tea-leaved willow shows high tolerance to root losses and is unlikely to be affected by realistic levels of root herbivory.

Dry evergreen montane forests in Ethiopia are severely threatened. The status of species composition and structure of forest vegetation are important indicators to understand the trends of threats on local plant communities. In the present study, we examined the floristic composition and structure of the Kibate Forest, Wonchi Highland, Ethiopia along environmental gradients. Sixty-six (30 m × 30 m) plots were established every 100 m interval along altitudinal gradients (2811‒3073 m a.s.l.) in five transect lines for vegetation and environmental data collection. In total, 125 vascular plant species belonging to 104 genera and 52 families were identified. Eighteen species (14%) were endemic to Ethiopia and Eritrea. The two most dominant families, Asteraceae (29 species) and Lamiaceae (eight species) accounted for 30% of the total number of species. The highest number of species (54%) was herbs. Four major community types (viz., Olinia rochetiana-Myrsine melanophloeos, Ilex mitis-Galiniera saxifraga, Erica arborea-Protea gaguedi, and Hagenia abyssinica-Juniperus procera) were identified. The highest species richness, evenness, diversity, and importance value index were in community types 2 and 4. About 82% of the species and all endemic taxa except five were recorded in these two community types. The most dominant woody species were O. rochetiana, E. arborea, Olea europaea subsp. cuspidata, Myrica salicifolia, I. mitis var. mitis, and H. abyssinica with different patterns of population structure. The results show that there was a weak correlation between species richness and altitude. Our findings confirm that environmental variables both with interactions (such as altitude) and without interactions (such as livestock grazing) significantly (p < 0.05) affect species richness. Anthropogenic activities and overgrazing by livestock appear to be the main threat in community types 2 and 3. Urgent management practices and conservation measures such as prohibiting forest clearing and overgrazing and planting indigenous trees through community participation should be considered in community types that are rich in endemic species but are highly threatened.

Larch caterpillars are widely distributed in the Great Xing’an boreal forests; however, the relationship between caterpillar defoliation dynamics and climatic factors is poorly understood. The aims of this study are to investigate the primary weather conditions that might influence forest defoliation and to identify the most important life stage of the larch caterpillar at which forest defoliation might be mitigated by incorporating more inhibitory influences from climatic factors. The life cycle of the larch caterpillar was partitioned into four stages and multiple linear regression and mixed effect models were combined with a relative weight analysis approach to evaluate the importance and influence of meteorological variables on defoliation dynamics. The results show that warmer temperatures in growing seasons and overwintering periods can increase the defoliation area, while rainy and humid growing seasons decrease the defoliation area. Total precipitation during the early instar larval period had the greatest power to explain the variance in defoliation dynamics and had a very strong inhibitory effect, followed by the accumulative temperatures of the late instar larval period which had a positive impact, and precipitation during the middle instar larval period which had a negative impact. Weather conditions during the early instar larval period had the greatest influence on the area defoliated and accounted for 40% of the explained variance. This study demonstrates that climatic warming and drying will increase the risk of larch caterpillar outbreaks in the Great Xing’an Mountains.

Pine wilt disease was first discovered in Dongtang town, Liaoning Province, China, in 2017. Monochamus saltuarius Gebler is a new vector of pinewood nematode and the only known vector in Liaoning Province. The biology of this pest has not been reported thus far; therefore, it is necessary to study its life history. During 2018 and 2019, we collected 138 and 491 adult M. saltuarius beetles, respectively, to analyze their eclosion from larva to adult stage. In mid-March, overwintering larvae began to feed (on xylem) and seek nutrition in preparation for pupation and eclosion. The adults began to appear in mid-April, and the population reached its peak in late May. The life span of the adults was 28–76 days. After approximately 1 week of supplemental nutrition (feeding on twigs), adults began to mate and lay eggs. The egg stage of M. saltuarius lasted 4–8 days. The larvae in Dongtang town have 4 instars and overwinter in tunnels as 3rd–4th instars. The 1st-instar stage lasted 3–9 days, the 2nd-instar stage lasted 11–23 days, the 3rd-instar stage lasted 30–130 days, and the 4th-instar stage lasted 44–180 days. The pupal stage lasted 7–12 days, and the life span of the adults was 28–76 days. In this study we systematically monitored the life history of M. saltuarius for the first time. Our objective was to lay a foundation for improving control of this pinewood nematode vector.

The composition of animal species and interactions among them are widely known to shape ecological communities and fine-scale (e.g., < 1 km) monitoring of animal communities is essential for understanding the relationships among animals and plants. Although the co-existence of large- and medium-sized species has been studied across different scales, research on fine-scale interactions of herbivores in deciduous broadleaf forests is limited. Camera trapping of large- and medium-sized mammals was carried out over a 1 year period within a 25 ha deciduous broadleaf forest dynamics plot in the Qinling Mountains, China. Fourteen species of large- and medium-sized mammals, including six carnivores, six ungulates, one primate and one rodent species were found. Kernel density estimations were used to analyse the diel or 24 h activity patterns of all species with more than 40 independent detections and general linear models were developed to explore the spatial relationships among the species. The combination of overlapping diel activity patterns and spatial associations showed obvious niche separation among six species: giant panda (Ailuropoda melanoleuca David), takin (Budorcas taxicolor Hodgson), Reeves’s muntjac (Muntiacus reevesi Ogilby), tufted deer (Elaphodus cephalophus Milne-Edwards), Chinese serow (Capricornis milneedwardsii David) and wild boar (Sus scrofa Linnaeus). Long-term fine-scale monitoring is useful for providing information about the co-existence of species and their interactions. The results demonstrate the importance for fine-scale monitoring of animals and plants for improving understanding of species interactions and community dynamics.