Forest management in several boreal countries is strongly focused on conifers because they are more productive, the technical quality of their stems is better, and their wood fibers are longer as compared to broadleaves. Favoring conifers in forest management leads to simple forest structures with low resilience and diversity. Such forests are risky in the face of climate change and fluctuating timber prices. Climate change increases the vitality of many forest pests and pathogens such as Heterobasidion spp. and Ips typographus L. which attack mainly spruce. Wind damages are also increasing because of a shorter period of frozen soil to provide a firm anchorage against storms. Wind-thrown trees serve as starting points for bark beetle outbreaks. Increasing the proportion of broadleaved species might alleviate some of these problems. This study predicts the long-term (150 years) consequences of current conifer-oriented forest management in two forest areas, and compared this management with silvicultural strategies that promote mixed forests and broadleaved species. The results show that, in the absence of damages, conifer-oriented forestry would lead to 5–10% higher timber yields and carbon sequestration. The somewhat lower carbon sequestration of broadleaved forests was counteracted by their higher albedo (reflectance). Mixed and broadleaf forests were better providers of recreational amenities. Species diversity was much higher in mixed stand and broadleaf-oriented silviculture at stand and forest levels. The analysis indicates that conifer-oriented forest management produces rather small and uncertain economic benefits at a high cost in resilience and diversity.

In this study, 28,691 genome sequences and 16,566 expressed sequence tags (ESTs) of Eucalyptus were derived from the GenBank database. A total of 2292 SSR loci were sought out from 1785 effective sequences. Through analyses of SSR loci information, the SSR motif length was negatively correlated with the abundance of the SSRs. In the EST sequences of Eucalyptus, triplet repeat motifs were the most abundant, and dinucleotide repeats motifs had the highest frequencies. Subsequently, 395 pairs of primers were designed based on the SSR loci. Using optimized SSR-PCR conditions, 340 pairs of primers were successfully screened, with a success rate of 86.1%. By construction of a maximum likelihood phylogenetic tree of six eucalypt species, represented by five species of the genus Eucalyptus and one of the genus Corymbia, the genetic relationships of Eucalyptus urophylla and E. camaldulensis suggested by this tree was found to differ from that suggested by traditional morphological taxonomy. The results provide insights for evaluating genetic diversity of Eucalyptus and analysis of Eucalyptus phylogenetics using SSR markers.

The Fabaceae (legume family) is one of the largest families of plants with a worldwide distribution and a major role in agriculture and in agroforestry. A hard seed coat impermeable to water is a typical feature of several species. Physical dormancy delays and reduces germination so that mechanical, physical and chemical scarification methods have been classically used to break seed dormancy of many species. We evaluate the effectiveness of a methodology to scarify seeds of several woody Fabaceae of ecological and economical importance, including Robinia pseudoacacia and Acacia dealbata and the shrubs Cytisus scoparius, C. multiflorus and Ulex europaeus. We describe the optimized use of a handheld rotary tool (HRT), and compare its effectiveness with other scarification methods reported to break dormancy such as boiling or dry heating. Total germination and/or speed of germination were enhanced after the application of the HRT, with germination percentages significantly higher than those achieved by other methods of scarification. Based on a thorough literature review, a mode of action for the HRT is suggested which could operate by breaking the physical and physiological dormancy of treated seeds through the combined action of coat abrasion and moderate temperatures. Considering these results, we recommend the application of this rapid, effective, low-cost and highly reproducible HRT method to break seed dormancy and enhance germination of these species and others with similar dormancy constraints.

The endangered Vatica mangachapoi, a long-lived, tropical tree with economic and ecological importance found in Hainan, China, was used to assess the hypothesis that historical human activities in Hainan’s tropical rain forest could have negative effects on the genetic diversity of V. mangachapoi. Three hundred and twenty individuals from 11 natural populations—which were classified into three groups according to levels of disturbance—were sampled and analyzed with ISSR markers. Although genetic diversity of V. mangachapoi is high at the species level, it is relatively low within populations. A significant genetic differentiation occurs among different disturbance levels. Significant isolation-by-distance indicated relevant historical anthropogenic changes. Our findings showed that historical human disturbances significantly increase the genetic differentiation and slightly decrease the genetic diversity of long-lived tree V. mangachapoi. Relevant targeting conservation actions were recommended.

Rich genetic polymorphism is important for plants to adapt to changes because it enables the plant to make anatomical, physiological and biochemical changes in response to abiotic stress. Geomorphologic characteristics, demographic interference and a cumulative decrease in freshwater influx in the Indian Sundarbans region have proved detrimental to some economically important plants. In this study, genetic polymorphism of three mangrove species, Xylocarpus granatum, Excoecaria agallocha, and Phoenix paludosa, was assessed using RAPD and ISSR molecular markers. X. granatum, already in distress in the Sundarbans, had the least genetic polymorphism, 14.56% in the RAPD analysis and 12.92% in the ISSR. Relatively higher genetic polymorphism was recorded for the profusely growing E. agallocha and P. paludosa: 24.66 and 26.4% in RAPD; 24.87 and 20.32% in ISSR analysis respectively. A UPGMA dendrogram constructed using the similarity matrix from RAPD, ISSR and combined data showed that for X. granatum, the least and highest salinity zones clustered together, whereas for E. agallocha and P. paludosa, higher and lower salinity areas clustered in different clades. Nei’s genetic diversity, calculated from RAPD and ISSR data, was also in accordance with 0.0637 and 0.0583 for X. granatum, respectively, much lower than 0.0794 and 0.0818 for E. agallocha and 0.0799 and 0.0688 for P. paludosa. This opposing degree of polymorphism might be attributed to the profusely growing E. agallocha and P. paludosa and precarious status of X. granatum throughout the Indian Sundarbans.

Geranylgeranyl pyrophosphate synthetase (GGPPS) has gained increasing attention as a key enzyme in terpene analysis. We designed specific primers based on plant GGPPS homologs and used reverse transcription polymerase chain reaction (RT-PCR) to obtain and identify PinGGPPS, a GGPPS gene sequence from Pinus massoniana, using bioinformatics tools. Quantitative PCR analysis of PinGGPPS expression levels in roots, pine needles, immature stems, and semilignified stems from 6-month-old P. massoniana showed that expression levels of PinGGPPS were highest in pine needles, followed by immature stems and semilignified stems, and lowest in roots. When we examined the correlation between PinGGPPS gene expression levels and resin productivity in 20 adult plants for 28 successive days, PinGGPPS expression levels presented a substantially linear distribution when plotted against their corresponding resin yields. In summary, we characterized the gene PinGGPPS for the first time in P. massoniana, and established a correlation between PinGGPPS gene expression levels and resin productivity, suggesting the importance of theory and production practice for P. massoniana.

A reliable, efficient anther culture system, the dominant technique for generating haploid plants in breeding programs, that can be used for generating transgenic poplar plants has been needed. In the present study, therefore, an anther culture system was developed using isolated mid- and late-uninucleate anthers of poplar (Populus simonii × P. nigra). From a combination of SSR and ploidy analyses, six double haploid and two haploid lines were characterized from 86 plants grown from 16 regenerated anther cultured lines. After 48 months of development, two plant lines from the regenerated plants maintained their haploid level in vitro for over 2 years. A number of haploid plants from the different lines were transferred to soil. The leaves of these transplants were then used as explants for transformation with the APETALA1 (AP1) gene using Agrobacterium tumefaciens. Overexpression of AP1 in haploid poplar induced early flowering with obvious petals when ectopically expressed. To our knowledge, this is the first report on changes in flowering time in AP1-trangenic poplar, which is important for elucidating the regulatory mechanism of tree flower development.

Our previous studies have revealed that the ThCAP gene plays a vital role in transgenic Populus (P. davidiana × P. bolleana) in response to cold stress. However, the regulatory mechanism of ThCAP gene expression has been unclear. In this study, the 5′ flanking region of the ThCAP promoter (PThCAP) was cloned using a genome-walking method. By analyzing cis-acting regulatory elements of PThCAP, a DRE motif and MYC and MYB elements were found to be located in the promoter. To identify the regulatory elements that control the expression of the ThCAP gene promoter, a series of deletion derivatives of PThCAP, P1–P5, from the translation start code (−1538, −1190, −900, −718 and −375 bp), were fused to the GUS reporter gene, and then each deletion was stably introduced into Arabidopsis thaliana plants. Deletion analysis of the promoter suggested that only the P2 fragment had strong GUS expression in leaves and roots of A. thaliana exposed to low temperature stress. These results suggest that this 290-bp region (−1190 to −900 bp), as an important part in PThCAP, was associated with cold tolerance of A. thaliana. Our results provide evidence for the regulatory mechanism of ThCAP gene involved in the response to cold stress, and that the gene is promising candidate gene for genetic improvement of crops.

Ectomycorrhizal (EM) networks provide a variety of services to plants and ecosystems include nutrient uptake and transfer, seedling survival, internal cycling of nutrients, plant competition, and so on. To deeply their structure and function in ecosystems, we investigated the spatial patterns and nitrogen (N) transfer of EM networks using ¹⁵N labelling technique in a Mongolian scotch pine (Pinus sylvestris var. mongolica Litv.) plantation in Northeastern China. In August 2011, four plots (20 × 20 m) were set up in the plantation. 125 ml 5 at.% 0.15 mol/L ¹⁵NH₄ ¹⁵NO₃ solution was injected into soil at the center of each plot. Before and 2, 6, 30 and 215 days after the ¹⁵N application, needles (current year) of each pine were sampled along four 12 m sampling lines. Needle total N and ¹⁵N concentrations were analyzed. We observed needle N and ¹⁵N concentrations increased significantly over time after ¹⁵N application, up to 31 and 0.42%, respectively. There was no correlation between needle N concentration and ¹⁵N/¹⁴N ratio (R² = 0.40, n = 5, P = 0.156), while excess needle N concentration and excess needle ¹⁵N/¹⁴N ratio were positively correlated across different time intervals (R² = 0.89, n = 4, P < 0.05), but deceased with time interval lengthening. Needle ¹⁵N/¹⁴N ratio increased with time, but it was not correlated with distance. Needle ¹⁵N/¹⁴N ratio was negative with distance before and 6th day and 30th day, positive with distance at 2nd day, but the trend was considerably weaker, their slop were close to zero. These results demonstrated that EM networks were ubiquitous and uniformly distributed in the Mongolian scotch pine plantation and a random network. We found N transfer efficiency was very high, absorbed N by EM network was transferred as wide as possible, we observed N uptake of plant had strong bias for ¹⁴N and ¹⁵N, namely N fractionation. Understanding the structure and function of EM networks in ecosystems may lead to a deeper understanding of ecological stability and evolution, and thus provide new theoretical approaches to improve conservation practices for the management of the Earth’s ecosystems.

The levels of heavy metals that accumulated in stemwood of mature trees grown for 20 years in a plantation in an abandoned peat quarry in areas that were fertilized with different amounts of domestic sewage sludge (180, 360, and 720 Mg ha⁻¹ on a dry basis) were compared with trees grown in a reference nonfertilized area. Included in the study was a hybrid poplar (Populus tremula × Populus tremuloides) developed for use as an energy crop, three local tree species and one introduced tree species. The concentrations of Cd, Cr, Cu, Ni, Pb and Zn in the stemwood of the trees grown in the fertilized and nonfertilized fields were determined, and found to be significantly lower than their respective concentrations in the soil. Cd and Cr were found only in several wood samples at concentrations close to the limits of detection or qualification; therefore, they were not analyzed further. A correlation analysis suggested that 75% of the correlations between the concentrations of heavy metals in the stemwood and the concentrations in the soil were negative. The ability of trees to accumulate the metals from soil in most cases decreased for Cu and Ni; however, the correlations were not as clear for Pb and Zn. The following sequence for the levels of heavy metals found in the stemwood of the analysed trees was Zn > Pb > Ni > Cu > (Cr, Cd). The results of this study showed that the levels of heavy metals in the studied wood would not exceed the permitted limits of heavy metal pollution in the air and ash when used for energy production.

Picea crassifolia and P. wilsonii, commonly used for afforestation in northern China, are increasingly likely to be subjected to high temperatures and soil drought stress as a result of global warming. However, little is known about the effects of these stresses on foliar photosynthesis in the two species. To investigate how photosynthetic characteristics and sensitivity respond to prolonged high temperatures and soil drought, foliar gas exchange and other closely related parameters were recorded from four-year-old seedlings of both species. Seedlings were grown under two temperature treatments (25/15 and 35/25 °C) and four soil water regimes [80, 60, 40 and 20% of maximum field capacity (FC)] for 4 months. Although all treatments significantly reduced photosynthetic rates (P _n) of both species, P. crassifolia exhibited greater photosynthetic acclimation than P. wilsonii. Differences in photosynthetic acclimation were mainly related to variations in stomatal conductance (Cond) and the maximum quantum yield of PSII (F _v/F _m) between treatments. Indeed, higher Cond and F _v/F _m in all treatments were shown for P. crassifolia than for P. wilsonii. Moreover, photosynthesis in P. crassifolia exhibited inherently lower temperature sensitivities (broader span for the temperature response curves; lower b) and higher thermostability (invariable b between treatments). Further, severe drought stress (20% FC) limited the survival of P. wilsonii. Our results indicate that P. wilsonii is more susceptible to high temperatures and soil drought stress. Planting P. crassifolia would be more expected to survive these conditions and hence be of greater benefit to forest stability if predicted increases in drought and temperature in northern China occur.

We isolated the essential oils from Boswellia ovalifoliolata N.P.Balakr and A.N.Henry using hydrodistillation, identified the obtained compounds using gas chromatography–mass spectrometry (GC–MS) and Fourier transform-infrared spectroscopy (FT-IR), and studied the photophysical and electrochemical properties using UV–visible and fluorescence spectroscopy and cyclic voltammetry. On the basis of GC–MS spectra, 38 compounds were identified in the essential oil from leaves and 26 in the oil from bark. The bark oil contained 13.44% β-Farnesene (sesquiterpene), 10.45% caryophyllene oxide (sesquiterpene) and 6.6% spathulenol, (2Z,6E)-(sesquiterpene alcohol); the leaf oil contained 11.1% spathulenol (sesquiterpene alcohol), 9.0% caryophyllene oxide (sesquiterpenoids) and 6.3% decyl acetate (ester). FT-IR spectra confirmed the presence of aliphatic aldehydes and ketones, carboxylic acid, alcohols, esters and ethers in both oil types. UV–visible absorption spectra showed maximum absorbance at 245, 290 and 402 nm for bark oil, and 250, 285 and 325 nm for leaf. Bark oil showed strong emission with maximum emission wavelength at 456 nm was higher than that of leaf oil at 414 nm. The essential oil had significant anti-inflammatory activity, and the reduction potential of the leaf oil was −0.44 and −0.56 eV for bark.

The effect of macadamia nut shell biochar on nitrogen, potassium, phosphorus, magnesium, calcium and sodium concentrations in potting mix used to grow Eucalyptus nitens seedlings was investigated in a glasshouse experiment. The treatments combined two fertiliser rates (50 and 100% rate of the commercial mix commonly used in forestry nurseries) with eight biochar rates (0, 2, 5, 10, 20, 50, 80 and 100 t ha⁻¹) arranged in a randomised complete block with three replicates of four sample plants. Nutrients were quantified in the potting mix and seedling leaves at four destructive harvests 135, 177, 219 and 269 days after planting. Biochar significantly increased nitrate-N, Colwell P, Colwell K and exchangeable Na and reduced ammonium-N, Mg and Ca concentrations in the potting mix. Seedling leaf concentrations of P, K and Na were increased by biochar application, while N remained dependent on fertiliser rate only. Mg and Ca leaf concentrations decreased in response to increasing biochar rates. Elevated nitrate-N and decreased ammonium-N concentrations suggest that biochar might have increased nitrification in the potting mix. We presumed that biochar mediated processes that reduced uptake of P and K when high doses of biochar were combined with full fertilisation. Changes in potting mix K, Na, Mg and Ca were consistent with selective adsorption of ions to biochar surfaces.

Snow/wind damage is one of the important natural disturbances in forest ecosystems, especially in a montane secondary forest. However, the effects of snow/wind damage remain unclear which affects the management of these forests. Therefore, we investigated the responses of species, individual tree traits and stand structure to snow/wind damage in a montane secondary forest. Results show that, amongst the canopy trees, Betula costata exhibited the most uprooting, bending and overall damage ratio (the number of damaged stems to the total number of stems in a plot); Quercus mongolica showed the highest breakage ratio and Fraxinus mandshurica and Juglans mandshurica the least overall damage ratios. Among the subcanopy trees, Carpinus cordata, Acer mono, Acer tegmentosum and Acer pseudo-sieboldianum showed the least uprooting and breakage, and the most bending damage. A. pseudo-sieboldianum demonstrated the lowest breakage and highest bending damage ratios. These findings indicate that different species have various sensitivities to snow/wind damage. Larger trees (taller, wider crowns) tend to break and become uprooted, while smaller trees are bent or remain undamaged, suggesting that tree characteristics significantly influence the types of damage from snow and wind. Stands of Q. mongolica and B. costata had the highest damage ratios, whereas A. pseudo-sieboldianum had the lowest snapping ratio. In summary, the severity and type of snow/wind damage are related to individual tree attributes and stand-level characteristics. Therefore, selection of suitable species (e.g., shorter, smaller with deep root systems, hard wood, bending resistance and compression resistance) and appropriate thinning are recommended for planting in the montane secondary forests.

Understanding population structure provides basic ecological data related to species and ecosystems. Our objective was to understand the mechanisms involved in the maintenance of Quercus aquifolioides populations. Using a 1 ha permanent sample plot data for Q. aquifolioides on Sejila Mountain, Tibet Autonomous Region (Tibet), China, we analyzed the population structure of Q. aquifolioides by combining data for diameter class, static life table and survival curve. Simultaneously, the spatial distribution of Q. aquifolioides was studied using Ripley’s L Function in point pattern analysis. The results showed: (1) Individuals in Q. aquifolioides populations were mainly aggregated in the youngest age classes, that accounted for 94.3% of the individuals; the older age classes had much smaller populations. Although the youngest age classes (Classes I and II) had fewer individuals than Class III, the total number of individuals in classes I and II was also greater than in classes IV to IX. In terms of tree height, few saplings, more medium-sized saplings and few large-sized trees were found. The diameter class structure of Q. aquifolioides populations formed an atypical ‘pyramid’ type; the population was expanding, but growth was limited, tending toward a stable population. (2) Mortality of Q. aquifolioides increased continuously with age; life expectancy decreased over time, and the survivorship curve was close to a Deevey I curve. (3) The spatial distribution pattern of Q. aquifolioides varied widely across different developmental stages. Saplings and medium-sized tree showed aggregated distributions at the scales of 0–33 m and 0–29 m, respectively. The aggregation intensities of saplings and medium-sized trees at small scales were significantly stronger than that of large-sized trees. However, large-sized trees showed a random distribution at most scales. (4) No correlation was observed among saplings, medium- and large-sized trees at small scales, while a significant and negative association was observed as the scale increased. Strong competition was found among saplings, medium- and large-sized trees, while no significant association was observed between medium- and large-sized trees at all scales. Biotic interactions and local ecological characteristics influenced the spatial distribution pattern of Q. aquifolioides populations most strongly.

The Natural Forest Protection Program (NFPP) is one of the key ecological forestry programs in China. It not only facilitates the improvement of forest ecological quality in NFPP areas, but also plays a significant role in increasing the carbon storage of forest ecosystems. The program covers 17 provinces, autonomous regions, and municipalities with correspondingly diverse forest resources and environments, ecological features, engineering measures and forest management regimes, all of which affect regional carbon storage. In this study, volume of timber harvest, tending area, pest-infested forest, fire-damaged forest, reforestation, and average annual precipitation, and temperature were evaluated as factors that influence carbon storage. We developed a vector autoregression model for these seven indicators and we studied the dominant factors of carbon storage in the areas covered by NFPP. Timber harvest was the dominant factor influencing carbon storage in the Yellow and Yangtze River basins. Reforestation contributed most to carbon storage in the state-owned forest region in Xinjiang. In state-owned forest regions of Heilongjiang and Jilin Provinces, the dominant factors were forest fires and forest cultivation, respectively. For the enhancement of carbon sequestration capacity, a longer rotation period and a smaller timber harvest are recommended for the Yellow and Yangtze River basins. Trees should be planted in state-owned forests in Xinjiang. Forest fires should be prevented in state-owned forests in Heilongjiang, and greater forest tending efforts should be made in the state-owned forests in Jilin.

Aboveground biomass and carbon stock in the largest sacred grove of Manipur was estimated for trees with diameter >10 cm at 1.37 m height. The aboveground biomass, carbon stock, tree density and basal area of the sacred grove ranged from 962.94 to 1130.79 Mg ha⁻¹, 481.47 to 565.40 Mg ha⁻¹ C, 1240 to 1320 stem ha⁻¹ and 79.43 to 90.64 m² ha⁻¹, respectively. Trees in diameter class of 30–40 cm contributed the highest proportion of aboveground biomass (22.50–33.73%). The aboveground biomass and carbon stock in research area were higher than reported for many tropical and temperate forests, suggesting a role of spiritual forest conservation for carbon sink management.

Community forest management helps in mitigating deforestation and forest degradation by addressing the negative aspects of rural livelihoods such as poverty and social exclusion. It is important in regulating global climate by encouraging sequestration of carbon in shoots, roots and soils. We studied the status of community forest management, forest resource harvest and carbon stocks in two community forests of the mid hill region of central and western Nepal. The study was based on primary and secondary data collected through carbon stock measurement from field visits and allometric equations, household surveys, focus group discussions, key informant interviews, and review of past studies. Socioeconomic variables such as gender, age group, livestock and landholding status were related to resource utilization, conservation, and management of community forest. Forest resources such as timber, firewood, fodder and leaf litter were harvested in sustainable ways. People were involved in forest thinning, co-management meetings, guarding and planting trees for forest conservation and management. Density and carbon stock of trees increased gradually in comparison to a previous study. We recommend further research on other community forests for more accurate and better results.

We estimated forest biomass carbon storage and carbon density from 1949 to 2008 based on nine consecutive forest inventories in Henan Province, China. According to the definitions of the forest inventory, Henan forests were categorized into five groups: forest stands, economic forests, bamboo forests, open forests, and shrub forests. We estimated biomass carbon in forest stands for each inventory period by using the continuous biomass expansion factor method. We used the mean biomass density method to estimate carbon stocks in economic, bamboo, open and shrub forests. Over the 60-year period, total forest vegetation carbon storage increased from 34.6 Tg (1 Tg = 1 × 10¹² g) in 1949 to 80.4 Tg in 2008, a net vegetation carbon increase of 45.8 Tg. By stand type, increases were 39.8 Tg in forest stands, 5.5 Tg in economic forests, 0.6 Tg in bamboo forests, and −0.1 Tg in open forests combine shrub forests. Carbon storage increased at an average annual rate of 0.8 Tg carbon over the study period. Carbon was mainly stored in young and middle-aged forests, which together accounted for 70–88% of the total forest carbon storage in different inventory periods. Broad-leaved forest was the main contributor to forest carbon sequestration. From 1998 to 2008, during implementation of national afforestation and reforestation programs, the carbon storage of planted forest increased sharply from 3.9 to 37. 9 Tg. Our results show that with the growth of young planted forest, Henan Province forests realized large gains in carbon sequestration over a 60-year period that was characterized in part by a nation-wide tree planting program.

Replantation of degraded forest using rapid-growth trees can play a significant role in global carbon budget by storing large quantities of carbon in live biomass, forest floor, and soil organic matter. We assessed the potential of 20-year old stands of three rapid-growth tree species, including Alnus subcordata, Populus deltoides and Taxodium distichum, for carbon (C) storage at ecosystem level. In September 2013, 48 replicate plots (16 m × 16 m) in 8 stands of three plantations were established. 36 trees were felled down and fresh biomass of different components was weighed in the field. Biomass equations were fitted using data based on the 36 felled trees. The biomass of understory vegetation and litter were measured by harvesting all the components. The C fraction of understory, litter, and soil were measured. The ecosystem C storage was as follows: A. subcordata (626.5 Mg ha⁻¹) > P. deltoides (542.9 Mg ha⁻¹) > T. distichum (486.8 Mg ha⁻¹) (P < 0.001), of which 78.1–87.4% was in the soil. P. deltoides plantation reached the highest tree biomass (206.6 Mg ha⁻¹), followed by A. subcordata (134.5 Mg ha⁻¹) and T. distichum (123.3 Mg ha⁻¹). The highest soil C was stored in the plantation of A. subcordata (555.5 Mg ha⁻¹). The C storage and sequestration of the plantations after 20 years were considerable (25–30 Mg ha⁻¹ year⁻¹) and broadleaves species had higher potential. Native species had a higher soil C storage while the potential of introduced species for live biomass production was higher.

Masson pine stands infected by Pine wilt disease (PWD) in the Three Gorges Reservoir Region of central China were surveyed to quantify the immediate responses and subsequent trajectories of biomass, carbon (C), and nitrogen (N) in stand-level major ecosystem compartments. The biomasses of above- and belowground tree components, as well as of the understory, forest floor, and mineral soil (0–40 cm), were determined within each stand. C and N storage were also estimated for each ecosystem compartment. Overstory biomass decreased steadily with the extent of PWD infection. Understory biomass ranged from 1.97 to 4.16 Mg ha⁻¹, and the observed value for forest floor biomass was 12.89–22.59 Mg ha⁻¹. The highest mean C and N concentrations were found in the stem bark and needles of Masson pine, respectively, while the lowest were found in the semi- to fully decomposed layer of the forest floor and stem wood of Masson pine, respectively. The C and N storage of aboveground trees, tree roots, and the aboveground ecosystem decreased with the extent of PWD infection. However, the C and N contents of the understory, forest floor, and total mineral soil initially declined after PWD infection before recovering over the following several years. Those result concluded that the biomass, C, and N storage of different forest ecosystem compartments have experienced certain variations following the PWD epidemic. This is vital to understand the shifts in stand-level C and N allocation in PWD-damaged forest stands, as well as for predicting the responses of regional and global C and N cycling.

This study chose dominant tree species including Picea crassifolia, Pinus armandii and Pinus tabuliformis which are distributed in Qilian Mountains, Xiaolongshan Mountains, and Bailongjiang River. According to the different tree species, ages and components, we sampled leaves, branches, stems, and roots, and measured the contents of Nitrogen, Phosphorus, Potassium, along with soil fertility. The changes of N, P, and K contents in the different tree species were studied, and the relationship between nutrient content and environmental factors was analyzed. The results indicated that the content of P in all three species was the lowest (0.039–0.28 g kg⁻¹), while N content was the highest (0.095–1.72 g kg⁻¹). As the terminal organ of nutrient transport, the nutrient content of leaves was the highest. P. armandii (0.45 g kg⁻¹) had a higher nutrient concentration than P. tabulaeformis (0.19 g kg⁻¹) and P. crassifolia (0.29 g kg⁻¹). The nutrient content of each species was highest in a young forest, but lowest in a mature forest. The nutrient content of all three tree species was significantly affected by soil nutrient content, and negatively correlated with available soil nutrients.

Determining forest structural complexity, i.e., a measure of the number of different attributes of a forest and the relative abundance of each attribute, is important for forest management and conservation. In this study, we examined the structural complexity of mixed conifer–broadleaf forests by integrating multiple forest structural attributes derived from airborne LiDAR data and aerial photography. We sampled 76 plots from an unmanaged mixed conifer–broadleaf forest reserve in northern Japan. Plot-level metrics were computed for all plots using both field and remote sensing data to assess their ability to capture the vertical and horizontal variations of forest structure. A multivariate set of forest structural attributes that included three LiDAR metrics (95th percentile canopy height, canopy density and surface area ratio) and one image metric (proportion of broadleaf cover), was used to classify forest structure into structural complexity classes. Our results revealed significant correlation between field and remote sensing metrics, indicating that these two sets of measurements captured similar patterns of structure in mixed conifer–broadleaf forests. Further, cluster analysis identified six forest structural complexity classes including two low-complexity classes and four high-complexity classes that were distributed in different elevation ranges. In this study, we could reliably analyze the structural complexity of mixed conifer–broadleaf forests using a simple and easy to calculate set of forest structural attributes derived from airborne LiDAR data and high-resolution aerial photography. This study provides a good example of the use of airborne LiDAR data sets for wider purposes in forest ecology as well as in forest management.

Deforestation issues are more problematic when indigenous (adat) communities, living within a forest, have lived there for many generations. These adat communities, who employ traditional land-use, are frequently accused of encroaching on the forest. To understand existing and future trends in the spatial patterns of the expansion of traditional land-use and deforestation, we conducted a case study in the Kandilo Subwatershed using mixed methods with image interpretation, spatial modelling and sociocultural surveys to examine the interrelationships between physical conditions, community characteristics and traditional land-use expansion. We investigated community characteristics through household interviews, communication with key informants, and discussions with focus groups. By using an area production model, we were able to analyze the effect of improved farming systems, policy intervention and law enforcement on traditional land-use expansion and deforestation. Based on our examination of a 20-year period of traditional land-use activities in adat forests, the evidence indicated that the steeper the slope of the land and the farther the distance from the village, the lower the rate of deforestation. Our study found that customary law, regulating traditional land-use, played an important role in controlling deforestation and land degradation. We conclude that the integration of land allocation, improved farming practices and enforcement of customary law are effective measures to improve traditional land productivity while avoiding deforestation and land degradation.

Rapid changes in land-use in the Combretum–Terminalia woodlands of northwestern Ethiopia are mainly due to the increases in commercial farming and immigration. We used integrated ecological and social data collection techniques, including subdivision of the vegetation zone, vegetation survey, focus group discussions and key informant interviews, to identify genecological zones and set criteria for selection of viable populations of Boswellia papyrifera (Del.) Hochst in Ethiopia for conservation. Interviews of senior experts were supported with a rating method and involved 43 respondents and focused on identifying and weighting criteria and indicators of selection in a participatory way to prioritize populations for conservation. Using mean annual rainfall data, we reclassified the Combretum–Terminalia woodland vegetation region into three moisture zones (wet, moist and dry), and designated them as genecological zones for B. papyrifera conservation. A total of 35 woody species were identified at Lemlem Terara site in Metema district, and the Shannon diversity index and evenness were 2.01 and of 0.62, respectively. There were 405 adult trees, and 10 saplings and 3314 seedlings per ha. The trees were medium-sized with overall mean diameter at breast height (dbh) of 16.9 (±9.5) cm. Seedling recruitment was poor due to grazing, crop production and fire incidences. Through a multi-criteria decision analysis, five criteria and 20 quantitative indicators were identified and weighted to prioritize populations for conservation. These criteria in their descending order of importance are (1) forest ecosystem health and vitality, (2) forest cover and population structure of B. papyrifera, (3) productive function of the forest, (4) biological diversity in the forest, and (5) socioeconomic benefits of the forest to communities. Multivariate tests in the general linear model revealed significant differences among researchers and nonresearchers in rating the criteria and indicators, but not among foresters and nonforesters. Hence, participatory multi-criteria decision analysis should involve people from various institutions to rectify decisions on conservation of the species. Careful evaluation of the investment policy environment and engaging those government bodies that are responsible to allocate the dry forests for commercial farming is recommended before the proposed criteria are applied to select populations for conservation, thus ensuring subsequent use of the outcomes of such exercises and better reconciling conservation and agricultural production increment goals.

In modern wildlife ecological research, feces is the most common non-invasive source of DNA obtained in the field and polymerase chain reaction (PCR) technology based on microsatellite markers is used to mine genetic information contained within. This is especially the case for endangered species. However, there are risks associated with this genotyping method because of the poor quality of fecal DNA. In this study, we assessed genotyping risk across 12 microsatellite loci commonly used in previous tiger studies using blood and fecal DNA from captive Amur tigers (Panthera tigris altaica). To begin, we developed an index termed the accumulated matching rate of genotypes (R _m) between positive DNA (blood samples) and fecal DNA to explore the correct genotyping probability of a certain microsatellite locus. We found that different microsatellite loci had different genotyping risks and required different PCR amplification protocols. The genotyping errors we detected altered population genetic parameters and potentially impact subsequent analyses. Based on these findings, we recommend that: (1) four loci (E7, Fca094, Pti007 and Pti010) of 12 loci are not suitable for Amur tiger genetic research because of a low R _m and difficulty reaching a stable status; (2) the R _m of the 12 microsatellite loci plateaued differently, and considering limited budgets, amplification times of some loci could be increased when using fecal samples; and (3) future genetic analysis of wild Amur tigers should be corrected by genotyping error rates (1 − R _m).

Flax fiber (FF) was used to reinforce wood flour/high density polyethylene composites (WF/PE). WF/PE particles were uniformly mixed with FF via high-speed mixing and then extruded with a single screw extruder to prepare FF reinforced WF/PE composites (FF/WF/PE). Mechanical testing, dynamic mechanical analysis, scanning electron microscopy (SEM), creep measurement and Torque rheology were used to characterize the resulting composites. The results indicate that the mechanical performance of the composites could be remarkably improved by adding a limited amount of FF. The flexural strength and modulus increased by 14.6 and 51.4%, respectively (FF content of 9 wt%), while the unnotched impact strength could be increased by 26.5% (FF content of 12 wt%). The creep resistance and toughness of the composite was markedly improved without changing the plastic content of the composite material.

To investigate the effects of temperature and moisture content (MC) on acoustic wave velocity (AWV) in wood, the relationships between wood temperature, MC, and AWV were theoretically analyzed. According to the theoretical propagation characteristics of the acoustic waves in the wood mixture and the differences in velocity among various media (including ice, water, pure wood or oven-dried wood), theoretical relationships of temperature, MC, and AWV were established, assuming that the samples in question were composed of a simple mixture of wood and water or of wood and ice. Using the theoretical model, the phase transition of AWV in green wood near the freezing point (as derived from previous experimental results) was plausibly described. By comparative analysis between theoretical and experimental models for American red pine (Pinus resinosa) samples, it was established that the theoretically predicted AWV values matched the experiment results when the temperature of the wood was below the freezing point of water, with an average prediction error of 1.66%. The theoretically predicted AWV increased quickly in green wood as temperature decreased and changed suddenly near 0 °C, consistent with the experimental observations. The prediction error of the model was relatively large when the temperature of the wood was above the freezing point, probably due to an overestimation of the effect of the liquid water content on the acoustic velocity and the limited variables of the model. The high correlation between the predicted and measured acoustic velocity values in frozen wood samples revealed the mechanisms of temperature, MC, and water status and how these affected the wood (particularly its acoustic velocity below freezing point of water). This result also verified the reliability of a previous experimental model used to adjust for the effect of temperature during field testing of trees.

The objective of this study was to compare the wood properties related to wood pulp quality of two widely planted Acacia species viz. Acacia mangium Willd. and Acacia auriculiformis A. Cunn. Ex Benth. and their hybrid. Acid insoluble lignin content (Klason), mean stem density and fibre length differed considerably among the species and hybrids. A. mangium possessed a high percent of lignin content compared to A. auriculiformis and the Acacia hybrid. However, mean stem density of A. auriculiformis was higher than A. mangium and the hybrid. Fibre length of heartwood tissues was generally shorter than that of sapwood tissues. The hybrid had longer fibres than the parent species. Lignin was negatively correlated with mean stem density. Generally, the wood properties of the hybrid were superior to its parent species. The significant intraspecific variation observed for wood properties of Acacia species could be used in breeding superior hybrids combining desirable traits of the two species. Considering the difficulty involved in accurately measuring the lignin content compared to mean stem density, selection for plants with low lignin content can be achieved by indirect selection of high mean stem density.

Lumber moisture content (LMC) is the important parameter to judge the dryness of lumber and the quality of wooden products. Nevertheless the data acquired are mostly redundant and incomplete because of the complexity of the course of drying, by interference factors that exist in the dryness environment and by the physical characteristics of the lumber itself. To improve the measuring accuracy and reliability of LMC, the optimal support vector machine (SVM) algorithm was put forward for regression analysis LMC. Environmental factors such as air temperature and relative humidity were considered, the data of which were extracted with the principle component analysis method. The regression and prediction of SVM was optimized based on the grid search (GS) technique. Groups of data were sampled and analyzed, and simulation comparison of forecasting performance shows that the main component data were extracted to speed up the convergence rate of the optimum algorithm. The GS-SVM shows a better performance in solving the LMC measuring and forecasting problem.