The Normalized Difference Vegetation Index (NDVI), one of the earliest remote sensing analytical products used to simplify the complexities of multi-spectral imagery, is now the most popular index used for vegetation assessment. This popularity and widespread use relate to how an NDVI can be calculated with any multispectral sensor with a visible and a near-IR band. Increasingly low costs and weights of multispectral sensors mean they can be mounted on satellite, aerial, and increasingly—Unmanned Aerial Systems (UAS). While studies have found that the NDVI is effective for expressing vegetation status and quantified vegetation attributes, its widespread use and popularity, especially in UAS applications, carry inherent risks of misuse with end users who received little to no remote sensing education. This article summarizes the progress of NDVI acquisition, highlights the areas of NDVI application, and addresses the critical problems and considerations in using NDVI. Detailed discussion mainly covers three aspects: atmospheric effect, saturation phenomenon, and sensor factors. The use of NDVI can be highly effective as long as its limitations and capabilities are understood. This consideration is particularly important to the UAS user community.

Carbon sequestration and water conservation are two of the key ecosystem services that forests provide for societal need to address environmental issues. Optimization of the dual services is the ultimate goal in forest management for mitigating global climate change and safeguarding terrestrial water balance. However, there are some tradeoffs between gain in forest productivity and ecosystem water balance. We conducted literature review based on published articles for learned knowledge on forest carbon fixation and hydrological regulations. Some knowledge gaps and research needs are identified by examining the inter-connections between forest carbon sequestration and water conservation. Past researches have helped gain basic understanding of the mechanisms and controls of forest carbon fixation and hydrological regulations as two separate issues. Tools and approaches are well established for quantifying and monitoring forest carbon and hydrological issues, operating at different spatial and temporal scales. There are knowledge gaps on how to design afforestation schemes facilitating enhanced ecosystem services in forest carbon sequestration and water conservation. For the top-down planning of afforestation in regions where water availability is anticipated to be problematic, the questions of how much and where to plant for given land availability, known environmental implications, and sustained regional development and livelihood need to be addressed. For local management considerations, the questions of what and how to plant prevail. Efforts are needed in joint studies of forest carbon sequestration and water conservation functionalities, specifically in relation to establishment and management of planted forests aiming for delivering regulatory ecosystem services in carbon sequestration, water conservation and other social values. We propose an integrated framework with dual consideration of carbon sequestration and water conservation in forest management for future research pursue.

In this study, a geometric model of a growing forest stand has been explored. The basic relationships considered link stand volume and stand density, diameter at breast height (DBH), mean DBH and mean height. The model provides simple formulas connecting the exponents of all the relationships. Application of the formulas to real forestry data provided a high level of predictions of an exponent from two others measured through regressions from empirical data. The Pinus sylvestris L. data were of a static nature, a collection of individual stands, while the Pseudotsuga menziesii (Mirb.) Franco data were dynamic, representing forest stand development over time. The ability of the model to predict exponents in the empirical data implies, on the one hand, a substantial level of similarity between the model and the forestry data. And, on the other hand, the model gives an example in which parameters of one relationship may be linked to parameters of another. Supposedly this kind of ‘relationship between relationships’ may be observed in forest stands undergoing active growth and competition-induced self-thinning.

A new model for predicting the total tree height for harvested stems from cut-to-length (CTL) harvester data was constructed for Pinus radiata (D.Don) following a conceptual analysis of relative stem profiles, comparisons of candidate models forms and extensive selections of predictor variables. Stem profiles of more than 3000 trees in a taper data set were each processed 6 times through simulated log cutting to generate the data required for this purpose. The CTL simulations not only mimicked but also covered the full range of cutting patterns of nearly 0.45 × 10⁶ stems harvested during both thinning and harvesting operations. The single-equation model was estimated through the multiple-equation generalized method of moments estimator to obtain efficient and consistent parameter estimates in the presence of error correlation and heteroscedasticity that were inherent to the systematic structure of the data. The predictive performances of our new model in its linear and nonlinear form were evaluated through a leave-one-tree-out cross validation process and compared against that of the only such existing model. The evaluations and comparisons were made through benchmarking statistics both globally over the entire data space and locally within specific subdivisions of the data space. These statistics indicated that the nonlinear form of our model was the best and its linear form ranked second. The prediction accuracy of our nonlinear model improved when the total log length represented more than 20% of the total tree height. The poorer performance of the existing model was partly attributed to the high degree of multicollinearity among its predictor variables, which led to highly variable and unstable parameter estimates. Our new model will facilitate and widen the utilization of harvester data far beyond the current limited use for monitoring and reporting log productions in P. radiata plantations. It will also facilitate the estimation of bark thickness and help make harvester data a potential source of taper data to reduce the intensity and cost of the conventional destructive taper sampling in the field. Although developed for P. radiata, the mathematical form of our new model will be applicable to other tree species for which CTL harvester data are routinely captured during thinning and harvesting operations.

Over the past 50 years, crown asymmetry of forest trees has been evaluated through several indices constructed from the perspective of projected crown shape or displacement but often on an ad hoc basis to address specific objectives related to tree growth and competition, stand dynamics, stem form, crown structure and treefall risks. Although sharing some similarities, these indices are largely incoherent and non-comparable as they differ not only in the scale but also in the direction of their values in indicating the degree of crown asymmetry. As the first attempt at devising normative measures of crown asymmetry, we adopted a relative scale between 0 for perfect symmetry and 1 for extreme asymmetry. Five existing crown asymmetry indices (CAIs) were brought onto this relative scale after necessary modifications. Eight new CAIs were adapted from measures of circularity for digital images in computer graphics, indices of income inequality in economics, and a bilateral symmetry indicator in plant leaf morphology. The performances of the 13 CAIs were compared over different numbers of measured crown radii for 30 projected crowns of mature Eucalyptus pilularis trees through benchmarking statistics and rank order correlation analysis. For each CAI, the index value based on the full measurement of 36 evenly spaced radii of a projected crown was taken as the true value in the benchmarking process. The index (CAI ₁₃) adapted from the simple bilateral symmetry measure proved to be the least biased and most precise. Its performance was closely followed by that of three other CAIs. The minimum number of crown radii that is needed to provide at least an indicative measure of crown asymmetry is four. For more accurate and consistent measures, at least 6 or 8 crown radii are needed. The range of variability in crown morphology of the trees under investigation also needs to be taken into consideration. Although the CAIs are from projected crown radii, they can be readily extended to individual tree crown metrics that are now commonly extracted from LiDAR and other remotely sensed data. Adding a normative measure of crown asymmetry to individual tree crown metrics will facilitate the process of big data analytics and artificial intelligence in forestry wherever crown morphology is among the factors to be considered for decision making in forest management.

Changes in tree mortality due to severe drought can alter forest structure, composition, dynamics, ecosystem services, carbon fluxes, and energy interactions between the atmosphere and land surfaces. We utilized long-term (2000‒2017, 3 full inventory cycles) Forest Inventory and Analysis (FIA) data to examine tree mortality and biomass loss in drought-affected forests for East Texas, USA. Plots that experienced six or more years of droughts during those censuses were selected based on 12-month moderate drought severity [Standardized Precipitation Evaporation Index (SPEI) -1.0]. Plots that experienced other disturbances and inconsistent records were excluded from the analysis. In total, 222 plots were retained from nearly 4000 plots. Generalized nonlinear mixed models (GNMMs) were used to examine the changes in tree mortality and recruitment rates for selected plots. The results showed that tree mortality rates and biomass loss to mortality increased overall, and across tree sizes, dominant genera, height classes, and ecoregions. An average mortality rate of 5.89% year⁻¹ during the study period could be incited by water stress created by the regional prolonged and episodic drought events. The overall plot and species-group level recruitment rates decreased during the study period. Forest mortality showed mixed results regarding basal area and forest density using all plots together and when analyzed the plots by stand origin and ecoregion. Higher mortality rates of smaller trees were detected and were likely compounded by density-dependent factors. Comparative analysis of drought-induced tree mortality using hydro-meteorological data along with drought severity and length gradient is suggested to better understand the effects of drought on tree mortality and biomass loss around and beyond East Texas in the southeastern United States.

An accurate and convenient method is essential for measuring the terminal velocity of seeds dispersed by wind. Systematic and random errors produced by existing methods lower the accuracy and convenience in determining seed terminal velocity. In this study, a video camera was used to record the falling process of forty-one species of wind-borne seed with eight appendage structures and seven aerodynamic behaviors in a settling tower at a speed of 50 frames per second (fps). The videos were analyzed by Quick Time Player to determine seed acceleration height, acceleration time, and terminal velocity. The results showed that acceleration height and time, terminal velocity, and the difference between terminal velocity and descent velocity (DTD) increased with wing loading. Compared with dropping methods, the camera recording method eliminated the effect of acceleration and corrected seed terminal velocity. Based on wing loading, release heights were determined for accurate measurement of terminal velocity of different seeds. This method, due to its inexpensive equipment, high accuracy, easy observation and operation, can be applied to measure the terminal velocity of wind dispersed seeds, and provides a promising method in exploring the dispersal process of seeds.

The Atlantic Forest is one of the largest and most biodiverse rainforests of South America but anthropogenic activities are drastically changing these landscapes. The invasion of alien or exotic species is one of the greatest threats to biodiversity. There are few studies of invasive species in tropical Brazilian ecosystems. This research examines growth and ecological aspects of Syzygium cumini and Clitoria fairchildiana, two invasive tree species in the Pedra Branca State Park, an Atlantic Forest remnant in southeastern Brazil. Both species were successfully dated, indicating an average age of 58 and 31 years, respectively. A positive relationship between growth and precipitation of the previous growing season suggests an ecological adaptive strategy, which could be facilitating their invasion into the environment. Cumulative growth diameter curves indicate slow and fast growth rates for S. cumini and C. fairchildiana, respectively. Growth release episodes detected in the tree rings indicate increased anthropogenic disturbances over the last 50 years.

The study of plant species abundance distribution (SAD) in natural communities is of considerable importance to understand the processes and ecological rules of community assembly. With the distribution of tree, shrub and herb layers of eight natural communities of Toona ciliata as research targets, three different ecological niche models were used: broken stick model, overlapping niche model and niche preemption model, as well as three statistical models: log-series distribution model, log-normal distribution model and Weibull distribution model, to fit SAD of the different vegetation layers based on data collected. Goodness-of-fit was compared with Chi square test, Kolmogorov–Smirnov (K–S) test and Akaike Information Criterion (AIC). The results show: (1) based on the criteria of the lowest AIC value, Chi square value and K–S value with no significant difference (p > 0.05) between theoretic and observed SADs. The suitability and goodness-of-fit of the broken stick model was the best of three ecological niche models. The log-series distribution model did not accept the fitted results of most vegetation layers and had the lowest goodness-of-fit. The Weibull distribution model had the best goodness-of-fit for SADs. Overall, the statistical SADs performed better than the ecological ones. (2) T. ciliata was the dominant species in all the communities; species richness and diversity of herbs were the highest of the vegetation layers, while the diversities of the tree layers were slightly higher than the shrub layers; there were fewer common species and more rare species in the eight communities. The herb layers had the highest community evenness, followed by the shrub and the tree layers. Due to the complexity and habitat diversity of the different T. ciliata communities, comprehensive analyses of a variety of SADs and tests for optimal models together with management, are practical steps to enhance understanding of ecological processes and mechanisms of T. ciliata communities, to detect disturbances, and to facilitate biodiversity and species conservation.

This research was carried out on nine provenances from the north Western Ghats to quantify proximate principles, mineral matter, total phenols and other phytochemicals in Melia dubia drupe pulp. Drupe biometric, biomass attributes, proximate principles, mineral matter and total phenols differed significantly among the provenances. The average drupe length and width was 26.5 and 22.3 mm, respectively. Average drupe and pulp fresh weight, pulp dry weight and stone weight were 783.1, 552.1, 165.1, and 179.8 g/100 drupes, respectively. Pulp, dry matter and moisture per cent were 70.5%, 29.9% and 70.0%, respectively. Average crude fibre, protein, ether extract, total ash and nitrogen- free extract were 8.3%, 7.6%, 5.1%, 6.3%, and 72.6%, respectively. Average Ca, Mg, P and K levels were 0.5%, 0.2%, 0.2%, and 2.0%, respectively. Total phenols were 0.4%. Cluster analysis showed that the study area may be divided into three distinct provenances, each having different drupe traits and proximate composition, including mineral components. Gas-chromatography mass-spectrometry analysis revealed 27 phytochemicals, many of which possess beneficial biological attributes. The implications of this provenance variation study should be useful for future improvement in terms of better drupe pulp nutrition for livestock feed. Further study suggests that M. dubia pulp could be categorized as a good feed source with low fibre, energy, fat and mineral levels. All proximate parameters, mineral matter content and total phenols are within prescribed limits.

Wetland restoration had been implemented for more than two decades in Sanjiang Plain, Northeast China. To assess the restoration efficiency of wetland vegetation, we investigated plants composition of community, plant species diversity and aboveground biomass of restored sites in a chronosequence of restoration (1, 2, 3, 6, 8, 11, 15 and 25 years) in the Sanjiang Nature Reserve. As comparison, we also investigated the same factors in a cropland and a natural marsh adjacent to the restored sites. The results showed that wetland plant species can invade quickly after croplands were abandoned when there were suitable hydrology conditions. On the early stage of the restoration, weeds were main plant species in the restored sites. Wetland species appeared at the same time but differed from the dominant species from the adjacent natural marshes. Common native wetland species could dominance the community after 3-year restoration. Species richness and diversity increased on the early stage, and then decreased to the similar level of the natural marsh with the extension of restoration. Plant biomass could restore easier than the species composition and diversity. Our results indicated that plant species composition and diversity of abandoned reclaimed wetlands can restore gradually by natural succession in Sanjiang Plain. However, 25-year restoration site had similarity index of only 56% with the natural marsh, which revealed that two decades are not enough for complete restoration of vegetation.

African teak (Milicia excelsa (Welw.) C.C. Berg) is an endangered multi-use species. Understanding the impact of climate change on the distribution of this species may improve the ability to anticipate or recognize its decline or expansion and to take appropriate conservation measures if necessary. Ecological niche modeling was projected in geographical space to study the current and future distribution of M. excelsa in Bénin. MaxEnt was used to estimate the potential geographic distribution of the species under two Representative Concentration Pathways (RCP). Miroc 5 summaries and two RCP 4.5 and RCP 8.5 scenarios were used as predictor variables for projections of the geographic potential of this species. The performance of the model was assessed by the area under the curve (AUC), true skill statistics (TSS) and partial receiver operating characteristics (Partial ROC). From the results, M. excelsa was more a secondary species in the Guinean climatic zone and part of the Sudanian-Guinean and Sudanian climatic zone. The projections show a significant decrease in suitable habitats for the species from the two RCP scenarios. Only a part of the Guinean climatic zone remained suitable and few protected areas will conserve in situ M. excelsa. For the sustainable conservation of M. excelsa, it is essential to strengthen the protection of sacred forests located in the Guinean climatic zone.

Urban trees provide vital ecosystem services such as mitigating heat island, improving air quality by removing various air pollutants, capturing rainwater, and acting as topsoil carbon storage. The aesthetic value of urban trees is also another feature that has to be considered in the context of urban greening. Classical criteria for the selection of urban trees have to respond to new challenges imposed to the cities in a near future. Global climate change factors increase the harshness of our cities, and thereby the plant resilience to abiotic stresses has also to be seriously considered for planning the urban greening. Red-leafed species, characterized by the permanent presence of foliar anthocyanins, show a greater tolerance to different environmental cues than green-leafed species commonly used in our cities. In addition, red tree species own a great aesthetic value which has been underestimated in the context of urban areas, especially in the harsh Mediterranean cities. In this study, we emphasize the “privilege of being red” from different point of view, in order to drive the attention to the possibility to increase the use of red-leafed species for urban “greening”. Some possible negative aspects related to their use are rebutted and the direction of future researches are proposed.

The rapid rate of deforestation in Côte d’Ivoire has led to loss of plant species diversity and also threatens some commercial tree species with extinction. Some reforestation and afforestation has been completed. However, for some species, the numbers of surviving transplants has declined. Hence, it is necessary to develop properly adapted and resilient genotypes that can effectively support the programs of forest restoration. In this context we evaluated the effects of the provenances of seeds and of various treatments on the germination rates and on plant growth of four commercial trees species (Pycnanthus angolensis, Terminalia superba, Mansonia altissima and Pterygota macrocarpa). We analyzed these parameters for seeds of three provenances (Daloa, Akoupé and Daoukro) of four species and for thirty plants aged 6 months per provenance. Time to begin germination and time to reach maximum germination were similar among species, and were not influenced by either treatment or provenance. Untreated seeds and those soaked for 24 and 48 h in water at room temperature yielded the highest germination rates, irrespective of species or provenance. The one exception was P. angolensis, for which no germination was recorded. Within species, some provenances produced higher germination percentages than did others. No clear relationship was computed between the germination rate and the morphometric characteristics of the seeds which varied significantly between provenances. Plant growth and morphological variability also depended greatly on provenance. Genetic factors might be implicated, therefore provenance trials should be undertaken and evaluated. Furthermore, molecular analysis should be undertaken to confirm the implications of genetic factors and allow for genetic selection.

Korean pine (Pinus koraiensis Siebold & Zucc.) in Northeastern China has been genetically improved to increase seed yields in addition to timber. To assess seed yield variability and select highly productive clones, 14 cone, seed and nut traits were measured and analyzed. Variance analysis showed that all clones were significantly different in various traits (P < 0.01). Phenotypic coefficients of variation and repeatability of traits ranged from 9.1 to 34.4% and from 27.5 to 97.7%, respectively. Except for the cone layer and cone seed numbers, the other traits were positively or negatively correlated. Three principal components were identified. Seed and nut traits were the most important traits in the first principal component, and cone traits more important in the second. Using correlation and principal component analyses, cone number and other traits were selected to evaluate materials. Twenty-two clones were selected using a selection rate of 10% based on cone number independently or other combined traits. The genetic gain for different traits ranged from 6.2 to 24.3%. The selected elite clones can supply seedlings for reforestation and the selection method can provide a theoretical basis for selection in other conifer species.

High potential productivity together with short rotation periods have made hybrid aspen an interesting option for wood production on former arable land in Nordic countries. In this study, some of the oldest active experimental plots with hybrid aspen in Sweden were remeasured at 23–30 years of age. A main aim was to assess age and productivity at the time of maximum mean annual volume increment. In addition, the influence of commercial thinning on stand development and differences in genetic gain among clones were investigated. Data from five experiments in southern Sweden were used, including three genetic trials, one demonstration stand with a clone mixture and one stand regenerated from root suckers. The three genetic trials were treated as single plot experiments, subject to a standard thinning program. In the remaining experiments, different thinning strategies were tested in a balanced block design. Volume growth had culminated or was close to maximum at age 25–30 years. Mean annual stem volume increment at culmination was 20–22 m³ ha⁻¹ a⁻¹. Dominant height reached 30–35 m at 28–30 years of age. Mean diameter at breast height was 27–29 cm after 29–30 years in the genetic trials. Clonal ranking based on diameter at age 7–9 years was positively correlated with the ranking at the final measurement in the genetic trials, 20 years later. This indicates that clones can be selected for superior growth based on results from young trials. More intense thinning programs increased the mean diameter compared to light thinning. The study indicates that one or two early and relatively heavy thinnings can promote the development of crop trees, without jeopardizing total volume production during a rotation of 25–30 years.

Height-to-diameter ratios (HD) are an important measure of the stability, density and competition of forest stands. It reflects the vertical growth of the trees, the vulnerability of the forest canopy structure and influences volumetric production. HD ratios vary according to tree size, availability of resources for growth, stand density and species composition. Data were taken from 210 trees and a regression technique of generalized linear models for the HD ratio applicable for forest structure conservation was developed. The objective of this study was to model the HD ratios of dominant and co-dominant trees of Araucaria angustifolia according to morphometric, dendrometric, annual diameter increment, stand density, and age variables in three sites in southern Brazil. The results show that the HD ratio decreases with increasing age, crown area and basal area, and increases with stand density and annual diameter increment. Accuracy of the developed equations was demonstrated by the values of deviation, Bayesian and Akaike criteria. The results are of interest to forest managers since they make decisions about silvicultural operations. Growth continuity and forest production indicate that any intervention should be directed at younger trees of smaller sizes, and that one of the main management factors for stand stability and growth is the formation of the stand and its capture of light.

The rooting capacity of Pinus massoniana is poor, especially for mature trees, and has prevented the development of clonal forestry for P. massoniana. In this study, we varied explant types, subculture times and exogenous hormones for plantlet regeneration and assessed shoots for rooting rate and root number for P. massoniana. Following five repetitive grafts, new shoots from grafts used as explant sources were rejuvenated as observed from juvenile shoot morphology and anatomy, leading to greatly enhanced plant regeneration in comparison to that of mature materials from 26-year-old P. massoniana trees. The rooting capacity of subcultured shoots increased with successive subcultures, reaching a peak at 20 subcultures with 35–40 days per subculture. However, rooting performance was significantly reduced after 30 subcultures. The addition of naphthaleneacetic acid (NAA) plus indoleacetic acid in the medium improved the root number, but the combination of exogenous NAA with paclobutrazol (PBZ) increased rooting rate and root number. We thus greatly improved the rooting capacity of mature P. massoniana trees by optimizing explant types (rejuvenated), subculture times (20 subcultures, 35–40 days per subculture) and addition of NAA + PBZ to the rooting medium. The conditions can be used for efficient plantlet regeneration of P. massoniana.

Tachi-branco (Tachigali vulgaris, L.F.Gomes da Silva & H.C.Lima) is a leguminous tree species native to the Amazon rainforest that has drawn attention for its remarkably fast growth, a required trait for biomass/bioenergy plantations. In evaluations of biomass production and wood properties of T. vulgaris planted in homogeneous plantations at different spacings in the Amazonian state of Pará, Brazil, biomass of 7-year-old trees was quantified for individual trees and the entire population. Wood was also sampled to assess properties relevant to bioenergy applications. The choice for spacing dimension for planting nonclonal T. vulgaris should consider whether the priority is greater productivity per tree, achieved with greater spacings (9.0 m² and 12.0 m²), or productivity per area, achieved with closer spacings (6.0 m² and 7.5 m²). Genetic variability of the T. vulgaris seed stand and/or high heritability of wood traits overcame the effect of different spacing on all morphological, physical, chemical and energetic properties of T. vulgaris wood. This species has moderate basic density when cultivated at spacings larger than 6 m² and net heating value above 7.95 MJ/kg, which is suitable for bioenergy purposes. The high variation in wood properties within tree spacing is strongly indicative of great potential for genetic breeding. The fast growth and the suitable moderate wood basic density confirm the outstanding potential of homogeneous plantations of T. vulgaris for providing wood for bioenergy.

The objective of this research was to improve the growth and biomass of Pterocarpus santalinus L.f. (an endangered leguminous tree) using native microbial symbionts such as arbuscular mycorrhizal fungi and Rhizobium associated with native populations of P. santalinus. The native arbuscular mycorrhizal fungi isolated from P. santalinus soils were identified as (1) Glomus fasciculatum; (2) Glomus geosporum; and Glomus aggregatum. A nitrogen-fixing microbial symbiont was isolated from the root nodules of P. santalinus and identified as Rhizobium aegyptiacum by 16s rRNA gene sequencing. These microbial symbionts were inoculated individually and in combination into P. santalinus seedling roots. After 90 days, growth and biomass had improved compared with uninoculated controls. Shoot and root lengths, number of leaves, stem circumference, number of root nodules, biomass, nutrient uptake and seedling quality index were significantly increased by a combined inoculation of arbuscular mycorrhizal fungi + Rhizobium aegyptiacum. It was concluded that native microbial symbionts positively influenced P. santalinus seedling growth which will be helpful for successful field establishment.

In order to further understand the effects of drought stress on hydraulic characteristics and the relationship between hydraulic conductivity and aquaporins or water channels of root systems of three wolfberry cultivars (Lycium chinense Mill.), hydraulic conductivity of 2-year-old pot-grown seedlings was measured under drought stress, rewatering, and treatment with exogenous mercuric chloride and β-mercaptoethanol. Under moderate and severe drought stress levels, the most significant decrease of hydraulic conductivity was 37.3% and 24.0%, respectively, in the ‘Ningqi 5’ cultivar compared with the non-stressed control. After rewatering, the rate of recovery in specific conductivity was most rapid in the ‘Mengqi 1’ cultivar, at 0.058 and 0.072 kg MPa⁻¹ m⁻² s⁻¹ h⁻¹ under moderate and severe drought stress levels, respectively. The ‘Mengqi 1’ cultivar had the highest recovery degree of hydraulic conductivity under two concentrations of β-ME (500 or 1000 μmol L^− 1), reaching 82.4% and 88.5%, respectively, of the initial conductivity. The adaptive capacity of hydraulic conductivity in the ‘Ningqi 5’ cultivar was weaker than in the ‘Ningqi 1’ and ‘Mengqi 1’ cultivars under drought stress. The recovery capacity of hydraulic conductivity in ‘Mengqi 1’ cultivar was stronger than the ‘Ningqi 1’ and ‘Ningqi 5’ cultivars after rewatering. Aquaporins of the ‘Ningqi 1’ cultivar root systems had the highest binding affinity with mercuric chloride, which was the most likely cause in the decrease in hydraulic conductivity, whereas aquaporins of ‘Mengqi 1’ root systems had the weakest binding affinity. The inhibitory effect of mercuric chloride was readily eliminated by β-mercaptoethanol in the ‘Mengqi 1’ cultivar. The hydraulic characteristics of this cultivar were more sensitive to drought, mercuric chloride and β-mercaptoethanol than the other cultivars.

Conservation of endangered plant species requires a prerequisite basic knowledge of their taxonomy and ecology. Unfortunately in the Cordillera Central Range, several species have not been studied, even though this area harbors a unique type of vegetation not found in other parts of the Philippines. This study documents the morpho-anatomical characteristics of Rhododendron subsessile Rendle, one of the unique and endangered flora in the area. The species exhibits a morphology typical of plants in high elevations, being a hardy shrub with small tough leaves, and showy pink flowers that rival those of commercial rhododendron species. New findings on the species morphology include a variable number of corolla lobes, stamens and a description of its fruits and seeds. The anatomical features of the species are reported here for the first time. The plant exhibits a typical dicot anatomy with dorsiventral leaves, woody stem and root system with the usual arrangement of periderm followed by secondary phloem, vascular cambium, secondary xylem with vessel elements and pith (in the case of the stem). A unique characteristic was identified as the biseriate upper epidermis of the leaf. Documenting the morphological and anatomical features of the species should prove valuable as input baseline information in formulating measures for its conservation.

Transcription factors can be used to engineer plants for enhanced productivity. However, the mechanism(s) by which the C2H2-type zinc finger transcription factor enhances pathogen resistance in cells is not fully understood. Here, Agrobacterium tumefaciens carrying the gene for Arabidopsis thaliana cysteine2/histidine2-type transcription factor 6 (ZAT6) was used to engineer rice (Oryza sativa L.), cotton (Gossypium hirsutum L.), and slash pine (Pinus elliottii Engelm.) to generate transgenic cell lines. Transgenic cells were then inoculated with the pathogenic bacterium Pseudomonas syringae. Compared to the control, cell viability of transgenic cells increased 39–47% and growth rate increased 9–15% by 7 days after inoculation in rice, cotton and slash pine. Acid phosphatase activity and alkaline phosphatase activity and transcript levels of Ca²⁺-dependent protein kinase genes OsCPK1, OsCPK2, OsCPK6, and OsCPK8 and mitogen-activated protein kinase genes OsMAPK1, OsMAPK2, OsMAPK3, and OsMAPK8 increased significantly in transgenic rice cells by 3 day after inoculation, and extracellular pH had decreased by 10–14% by 96 min after inoculation in transgenic rice, cotton and slash pine cells. These results suggest that ZAT6 enhances P. syringae resistance in plant cells by modulating transcription of CPK and MAPK and oxidase activity.

Salix L. (willow) is the largest genus of the family Salicaceae and plays an important role in riparian habitats, wetlands and in shrub tundra. Due to the different implications for the species belonging to this family, it is fundamental to identify molecular tools characterizing relevant clones. A set of six multilocus and multiallelic simple sequence repeat (SSRs) markers are presented, leading to 390 polymorphic fragments considered as single dominant markers and able to discriminate successfully 92 S. alba L. from 24 Salix spp. The polymorphic fragments have been used to perform genetic diversity studies, and to investigate population structures and cluster analysis in a germplasm collection. The results highlight the capability of the six SSRs to be powerful genetic resources in applied forestry research, both to distinguish S. alba clones from Salix spp. and to perform genetic population studies for breeding programs.

The basic leucine zipper (bZIP) transcription factor family is one of the largest and most diverse families in plants, regulating plant growth and development and playing an essential role in response to abiotic and biotic stresses. However, little is known about the biological functions of bZIP proteins in yellowhorn (Xanthoceras sorbifolium). Recently, 64 XsbZIP genes were identified in the yellowhorn genome and found to be disproportionately distributed in linkage groups. The XsbZIP proteins clustered into 11 groups based on their phylogenetic relationships with AtbZIP, ZmbZIP and GmbZIP proteins. Five intron patterns in the basic and hinge regions and additional conserved motifs were defined, both supporting the group classification and possibly contributing to their functional diversity. Compared to tandem duplication, the segment duplication greatly contributed to the expansion of yellowhorn bZIP genes. In addition, most XsbZIP genes harbor several stress responsive cis-elements in their promoter regions. Moreover, the RNA-seq and qRT-PCR data indicated XsbZIP genes were extensively involved in response to various stresses, including salt (NaCl), cold and abscisic acid, with possibly different molecular mechanisms. These results provide a new understanding of the biological functions of bZIP transcription factors in yellowhorn.

Catalpa fargesii is an important economic tree species used for furniture and timber production because of its high density and hardness. Its survival and growth are severely affected and primarily limited by drought stress. Thus, to better understand the mechanism of drought resistance in C. fargesii, we used qRT-PCR to reveal significantly different expression of three plasma membrane intrinsic protein genes: CfPIP1-1, CfPIP1-2 and CfPIP1-4. We then cloned their full-length cDNA sequences and characterized the encoded proteins. We analyzed the genes phylogenetically and predicted conserved motifs, domains, and secondary and tertiary structures. To verify the function of the CfPIP1 genes further, we ectopically expressed CfPIP1 transgenes in Arabidopsis thaliana. The results showed that CfPIP1-1, CfPIP1-2 and CfPIP1-4 had several characteristics of aquaporins. The transgenic plants grew better than the WT plants did under drought stress, and overexpression of the CfPIP1 genes increased the plant water content and resistance to drought. Thus, CfPIP1-1, CfPIP1-2 and CfPIP1-4 of C. fargesii play key roles in regulating the intracellular and extracellular water balance and in mediating the plant response to drought.

Picea mongolica is a conifer with a limited distribution in China and its taxonomic status is controversial. In order to explore genetic differences between P. mongolica and other nearby Picea species and to investigate its taxonomic status, phylogenetic relationships were analyzed between P. mongolica and Picea koraiensis, Picea meyeri and Picea wilsonii by three chloroplast gene sequences matK, chlB and atpA. The length of joint chloroplast sequence is 2379 bp. The fifteen haplotypes were identified by haplotype network analysis, among which two were major haplotypes and nine were unique. In addition, the genetic diversity of the sample collection species was inferred. Based on the haplotype network and Neighbor Joining phylogenetic tree analysis, P. mongolica was located on the basal clade of the phylogenetic tree which had more primitive taxa, and the genetic diversity of P. mongolica was highest. The significant differences between P. mongolica and these other Picea species were identified by this research.

The genus Hippophae includes deciduous shrubs or small trees, which provide many ecological, economic, and social benefits. We assembled and annotated the chloroplast genomes of sympatric Hippophae gyantsensis (Rousi) Lian and Hippophae rhamnoides Linn subsp. yunnanensis Rousi and comparatively analyzed their sequences. The full-length chloroplast genomes of H. gyantsensis and H. rhamnoides subsp. yunnanensis were 155,260 and 156,415 bp, respectively; both featured a quadripartite structure with two copies of a large inverted repeat (IR) separated by small (SSC) and large (LSC) single-copy regions. Each Hippophae chloroplast genome contained 131 genes, comprising 85 protein-coding, 8 ribosomal RNA, and 38 transfer RNA genes. Of 1302 nucleotide substitutions found between these two genomes, 824 (63.29%) occurred in the intergenic region or intron sequences, and 478 (36.71%) were located in the coding sequences. The SSC region had the highest mutation rate, followed by the LSC region and IR regions. Among the protein-coding genes, three had a ratio of nonsynonymous to synonymous substitutions (Ka/Ks) > 1 yet none were significant, and 66 had Ka/Ks < 1, of which 46 were significant. We found 20 and 16 optimal codons, most of which ended with A or U, for chloroplast protein-coding genes of H. gyantsensis and H. rhamnoides subsp. yunnanensis, respectively. Phylogenetic analysis of five available whole chloroplast genome sequences in the family Elaeagnaceae—using one Ziziphus jujube sequence as the outgroup—revealed that all five plant species formed a monophyletic clade with two subclades: one subclade consisted of three Hippophae species, while the other was formed by two Elaeagnus species, supported by 100% bootstrap values. Together, these results suggest the chloroplast genomes among Hippophae species are conserved, both in structure and gene composition, due to general purifying selection; like many other plants, a significant AT preference was discerned for most protein-coding genes in the Hippophae chloroplast genome. This study provides a valuable reference tool for future research on the general characteristics and evolution of chloroplast genomes in the genus Hippophae.

Prince Rupprecht’s larch (Larix principis-rupprechtii Mayr.), a deciduous conifer, widely grows in middle and high elevations of Northern China. Its natural distribution has sharply decreased and has become fragmented, which may have resulted in the loss of genetic variation. In this study, ten natural populations across the entire range of this species were analyzed using amplified fragment length polymorphism markers. A total of 309 loci were detected from 225 individuals of these populations, of which 261 (84.5%) were polymorphic. At the species level, the genetic diversity was high (average of the Nei’s genetic diversity H _e = 0.2602, and Shannon’s information index I = 0.3967). The results of molecular variance analysis showed that 90.71% of the genetic diversity occurred within populations. The genetic differentiation among populations was moderate as a whole (F _ST = 0.0929, G _ST = 0.1510), which is consistent with the moderate level of gene flow among populations (N _m = 2.8116). Based on the unweighted pair group method with arithmetic mean and STRUCTURE analysis, these populations were grouped into three genetically distinct clusters. The degree of inter-population differentiation (G _ST = 0.1338) for the south group was larger than that for the north group (G _ST = 0.0915). There was a significant correlation between genetic distance and geographic distance across the species range (r = 0.316, P < 0.05). Genetic diversity was significantly associated with longitude but not elevation or climatic factors. The populations with high genetic diversity from each cluster are therefore recommended for future conservation and management of this species.

Estimating the carbon storage of forests is essential to support climate change mitigation and promote the transition into a low-carbon emission economy. To achieve this goal, voluntary carbon markets (VCMs) are essential. VCMs are promoted by a spontaneous demand, not imposed by binding targets, as the regulated ones. In Italy, only in Veneto and Piedmont Regions (Northern Italy), VCMs through forestry activities were carried out. Valle Camonica District (Northern Italy, Lombardy Region) is ready for a local VCM, but carbon storage of its forests was never estimated. The aim of this work was to estimate the total carbon storage (TCS; t C ha⁻¹) of forest biomass of Valle Camonica District, at the stand level, taking into account: (1) aboveground biomass, (2) belowground biomass, (3) deadwood, and (4) litter. We developed a user-friendly model, based on site-specific primary (measured) data, and we applied it to a dataset of 2019 stands extracted from 45 Forest Management Plans. Preliminary results showed that, in 2016, the TCS achieved 76.02 t C ha⁻¹. The aboveground biomass was the most relevant carbon pool (48.86 t C ha⁻¹; 64.27% of TCS). From 2017 to 2029, through multifunctional forest management, the TCS could increase of 2.48 t C ha⁻¹ (+ 3.26%). In the same period, assuming to convert coppices stands to high forests, an additional TCS of 0.78 t C ha⁻¹ (equal to 2.85 t CO₂ ha⁻¹) in the aboveground biomass could be achieved without increasing forest areas. The additional carbon could be certified and exchanged on a VCM, contributing to climate change mitigation at a local level.

The objectives of this study were: (1) to determine carbon stock changes in the soil and forest floor of black pine (Pinus nigra subsp. pallasiana) plantations in Turkey; (2) to determine the effects of thinning on annual carbon accumulation in both; and, (3) to investigate relationships between annual carbon storage in soil and forest floor and stand characteristics of black pine. Samples were taken in 90 plots from stands at the pole (dbh = 11.0–19.9 cm) and sawlog (dbh = 20.0–35.9 cm) stages. Carbon analyses of soil and forest floor samples showed that in unthinned plantations significant organic carbon was sequestered an average of 1.47 Mg ha⁻¹ a⁻¹ in the soil and 0.20 Mg ha⁻¹ a⁻¹ in the forest floor. Organic carbon sequestered annually in the soil was significantly lower in thinned than in unthinned stands, while differences in the forest floor were insignificant. There were positive correlations between carbon sequestered in the soil and stand age, average DBH, mean stand height, basal area, and site index. Carbon sequestered the forest floor increased with basal area. As a result, carbon sequestered in the soil should not be ignored in greenhouse gas inventories because carbon stored belowground was approximately 70% of the aboveground pool.

This research estimates carbon sink and allocation in above- and below-ground biomass of a 12-year-old willow coppice plantation on fluvisol soil near the Vistula River (southern Poland). The plantation showed high C sink potential and sequestration rates. C sequestration by above-ground biomass was estimated at 10.8 Mg C ha⁻¹ a⁻¹. Accumulation in coarse roots was estimated at 1.5 Mg C ha⁻¹ a⁻¹ and in fine roots at 1.2 Mg C ha⁻¹ a⁻¹. Total C sequestered (above-ground biomass, coarse roots and fine roots) was estimated at 13.5 Mg C ha⁻¹ a⁻¹. These results confirm the potential of fast-growing plantations of willow to mitigate, over a short time span, the effects of high CO₂ concentrations.

The objectives for this study were to determine changes in soil organic carbon (SOC) components and water-stable aggregates for soil profiles from different ages of plantations of Liriodendron chinense and to clarify which organic carbon component is more closely associated with the formation and stability of soil aggregates. Three layers of soil (depths 0–20 cm, 20–40 cm, 40–60 cm) were collected from young, half-mature and mature stages of L. chinense. SOC, readily oxidizable organic carbon, chemically stable organic carbon and aggregate composition were determined. Intermediate stable organic carbon, the microbial quotient and aggregate stability (mean weight diameter) were calculated. SOC and aggregate stability in the L. chinense plantation did not increase linearly with an increase in L. chinense age; rather, they first decreased, then increased with increasing age of L. chinense. The microbial quotient had a negative effect on the level of organic carbon and the stability of aggregates, while chemically stable organic carbon had a positive effect, which explained 55.0% and 19.3% of the total variation, respectively (P < 0.01). Therefore, more attention should be paid of these two indicators in the future.

To elucidate the dynamics of aluminium (Al), an element potentially toxic and strongly affected by acidification processes, in soils, we selected two regions that were similar in relief, soil types, and vegetation cover but differed markedly in their history of acid precipitation: the Jizerské Mountains (anthropogenically acidified) and the Novohradské Mountains (naturally acidified) in the Czech Republic. The levels of Al forms (exchangeable and organically bound) associated with different environmental impacts were measured and univalent, divalent and trivalent Al species were quantified using HPLC/IC. Exchangeable and organically bound Al concentrations were higher in the anthropogenically acidified area. Only the concentrations of the least-dangerous species, the univalent, in organic soil horizons were similar for both mountains. The concentrations of exchangeable Al forms were correlated with Ca concentrations and with pH in the organic horizon. The known relationship of Al with soil pH was stronger in the mineral horizons. Relationships of exchangeable Al forms concentrations with sulphur concentrations or even more with the sulphur calcium molar ratio were found only in the Jizerské Mountains, not in the Novohradské. Generally, the obtained results support the hypothesis that mechanisms differed between natural and anthropogenic acidification.

The effect of seasons on the soil microbiome in a Larix gmelinii forest of Mohe, China, where winter temperatures are generally below − 40 °C, was evaluated with metagenomics analysis. Taxonomic profiling using sequencing information revealed that Proteobacteria, Actinobacteria, Acidobacteria and Verrucomicrobia were the dominant phyla in spring, summer, and fall, as were Bradyrhizobium, Chthoniobacter, Streptomyces, Acid Candidatus Koribacter at the genus level. Some species that were abundant in spring and fall greatly diminished in abundance in summer. Clusters of orthologous groups (COG) of proteins, carbohydrate-active enzymes (CAZy), Kyoto Encyclopedia of Genes and Genomes (KEGG) and NCBI databases were used to elucidate the function of diverse proteins and metabolites of the microbial community of L. gmelinii forest. COG analysis showed that fewer genes were detected in spring than in fall and summer, indicating that many soil microbes in the L. gmelinii forest were not tolerant to cold. Based on KEGG analysis, some pathways in the soil microbes were activated in spring and autumn and deactivated in summer. CAZy analysis revealed that most CAZy were more active in summer than in spring or autumn and were severely inhibited in the spring. Many functional pathways, proteins, and CAZy involved in the community changes were concerned with cold or heat resistance. Therefore, the soil in the L. gmelinii forest can be a valuable resource for further research on heat and cold tolerance of soil microbes.

The slope aspect is one of the most critical topographic factors in mountainous areas. Little is known, however, about the effect of the aspect on the ectomycorrhizal (ECM) fungal community. Additionally, we know very little about the composition of ECM fungal communities associated with Quercus variabilis, which is widely distributed in East Asia. In this study, we compared the richness, community composition, and exploration types of ECM fungi associated with Q. variabilis between predominantly south- and north-facing slopes in the Taihang Mountain, North China for the first time. DNA was extracted from the root tips of Q. variabilis, and Illumina MiSeq sequencing was used to identify ECM fungi. In total, 168 operational taxonomic units belonging to 28 genera were detected, and the ECM community was found to be dominated by Russula, Inocybe, Tomentella, Scleroderma, and Cortinarius. Compared with the north-facing slopes, the ECM communities on the south-facing slopes had higher diversity. The community composition and exploration types were directly affected by the slope aspect. Also, the aspect-induced edaphic variables, such as total phosphorus, total nitrogen, total potassium, pH, and soil water content, were important sources of variation in ECM fungal richness and distributions of exploration types. Different genera tended to be distributed in various slope aspects. Cenococcum, Genea, and Clavulina were significantly enriched in north-facing slopes, while Geopora, Helvelosebacina, Scleroderma, Gyroporus, Astraeus, Boletus, Tricholoma, Hebeloma, Cortinarius and unclassified Thelephoraceae were more abundant in south-facing slopes. Hydrophobic ECM fungi were obviously enriched in the south-facing slope, but there was no statistical difference between hydrophilic among the south- and north-facing slopes. Our study deepened our knowledge of the aspect-driven variation in ECM fungal communities associated with Q. variabilis.

Brachymeria lasus Walker is a solitary endoparasitoid that attacks the pupae of a wide range of lepidopteran hosts, including an important invasive species, the fall webworm (Hyphantria cunea Drury). We studied the relationship between temperature and development of B. lasus from egg to adult hatching. The results show a decrease in parasitoid development time from 34.4 days at 18 °C to 10.6 days at 32 °C. The minimum threshold temperature of B. lasus was 13.2 °C ± 1.7 °C, and the effective accumulated temperature was 210.3 ± 28.7 degree days. These results provide a basis for optimizing the production of this parasitoid. In addition, the effects of host size on offspring performance of B. lasus were investigated under laboratory conditions. Offspring longevity, size, and percentage of females were positively correlated with host size. Female offspring are larger and live longer than males. Furthermore, this research showed that parasitoid adults successfully emerged from approximately 27.9% of pupae. However, eclosion or hatching of H. cunea decreased dramatically, which may be due to damage caused by female B. lasus when testing hosts with their ovipositors or by feeding on them. The results suggest that B. lasus has the potential to become an efficient natural enemy for controlling H. cunea.

The hazelnut weevil (Curculio dieckmanni Faust.) is a major pest of Asian hazel (Corylus heterophylla Fisch.) in China. Dead hazelnut weevil larvae were examined and the associated pathogenic bacterium was identified as Serratia marcescens Bizio. This significantly shortened the lifespan of hazelnut weevil. Larval weight was reduced as a function of S. marcescens concentration and exposure time. The structure of infected midgut cells was altered, with necrosis of the wall tissues and many cells becoming dislodged, creating cavities. The S. marcencens strain inhibited digestive enzyme activity and protective enzymes in the midgut of adult hazelnut weevil. Inhibition on S. marcencens strain increased with treatment time. S. marcescens directly destroyed the midgut cells and interfered with digestive and protective enzymes. This decreased the food intake and increased mortality of hazelnut weevil. S. marcescens appears to be an effective bacterium for the control of hazelnut weevil but requires further study, including biological formulation development and field application.

This study evaluated boron diffusion from rods made of raw boron minerals, ulexite and colemanite with low water solubility, in comparison with di-sodium octaborate tetrahydrate (DOT). Scots pine (Pinus sylvestris L.) sapwood and heartwood blocks were conditioned to target moisture contents of 30%, 60%, and 90%. The rods were inserted into the blocks through treatment holes and boron diffusion was observed at three assay zones across the blocks after 7, 30, 60 and 90-day-incubation at room temperature. Ethylene glycol was also inserted into the holes to improve boron diffusion. Boron levels increased with increased wood moisture content. With some exceptions, boron in the assay zones did not tend to follow consistent amount gradients with distance from the treatment hole. Boron levels from ulexite rods were higher than those from colemanite rods, with DOT rods with the highest diffusion rates as a result of higher water solubility of DOT than ulexite and colemanite. The results suggest that ulexite-based rods may be useful in the presence of ethylene glycol in sapwood when wood is at high moisture content for extended periods.

We investigated the stain of fast-growing wood (Cunninghamia lanceolate, CL; Paulownia, PT) inoculated with three fungi (Arthrinium phaeospermum, AP; Vibrio anguillarum, VA; Aspergillacea, AS) to explore the new wood dyeing ways and the better combination of wood and fungi for dyeing. Only AP could dye on CL and PT. Especially for CL, its percentage of internal spalting, percentage of external spalting and dyeing depth were the highest (48%, 15% and 5.06 mm, respectively). Surprisingly, the bigger weight loss occurs on PT. The results showed that the dyeing effect of AP dyeing CL was the best, and the wood color change was obviously (Orange to dark red). AP could produce more pigments than the other two fungi (VA; AS), CL was more suitable for fungus staining than PT, indicating that AP could offered a new potential market and a chance for areas to earning higher income for CL. This research paves the way for improving color change was obviously (Orange to dark red). AP could produce more pigments than the other two fungi (VA; AS), CL was more suitable for fungus staining than PT, indicating that AP could offer a new potential market and a chance for areas to earn higher income for CL.