[Objective]In order to provide a basis for enhancing the stability of plantations and maintaining land fertility sustainable management of plantations, this study explores the suitable thinning intensities for Chinese fir plantations from the perspective of developing understory vegetation and improving community structure.[Method]Three intensities were used for the thinning of Chinese fir plantations in Jiangle State owned Forest Farm of Fujian Province in 2013, namely low (LT, 10%-25%), moderate (MT, 25%-35%),high (HT, 40%-50%), and the control (CK, no thinning).In 2016, all trees in the sample plots were measured and species diversity, coverage, biomass of the understory vegetation and soil properties were in vestigated.A one-way analysis of variance (ANOVA) and Tukey multiple comparisons were used for significance test and Pearson correlation analysis between understory vegetation and soil properties was conducted.[Result]Three years after thinning, there were no community formed for the three thinning intensities CK, LT and MT, with a coverage of 25.52%,52.81%,and 58.98% respectively. While the shrub-fern community formed with a coverage of 100%after a high intensity thinning. In the shrub layer, the richness index, Simpson index, Shannon-Wiener index, coverage and biomass significantly increased with increasing thinning intensity while the evenness index displayed an opposite relation with the thinning intensity. In the herb layer, the richness index, Simpson index, Shannon-Wiener index, evenness index, coverage and biomass all significantly increased with increasing thinning intensity. Three years after thinning, compared with the CK, the organic matter content of the topsoil (0-10 cm) under the treatments of LT, MT, and HT increased by 71.41%, 39.31%,and 98.10%,respectively; the total nitrogen content increased by 82.76%, 51.27%, and 115.87% respectively; the content of available nitrogen increased by 49.47%, 25.59%, and 42.22% respectively; the available phosphorus content increased by 138.29%, 112.23%, and 174.29% respectively; the contents of available potassium increased by -16.25%, -24.25%, and 16.27%, respectively. Thinning intensity had no significant effect on pH, total phosphorus content and soil physical properties of top soil.The coverage and biomass of the shrub layer were positively correlated (P<0.05) with the organic matter, total nitrogen, total phosphorus and available phosphorus contents of topsoil. The coverage of the shrub layer was also positively correlated (P<0.05) with available potassium content. The coverage of herb layer was not strongly correlated with soil physical and chemical properties and the biomass of herb layer was positively correlated (P<0.05) with soil organic matter, total nitrogen, total phosphorus, available nitrogen, and available phosphorus contents of topsoil. There was no significant correlation between coverage and biomass of the understory vegetation with soil pH and physical properties.[Conclusion]The understory vegetation in the un-thinned Chinese fir plantations had low species diversity, coverage and biomass, unable to form a community structure and lack of stability. Thinning can promote the development of understory vegetation, leading to the increases of biodiversity, coverage, and biomass of the understory vegetation, formation of community structure, and improvement of the ability to maintain the soil fertility, and it is particularly evident for the high intensity thinning. For young Chinese fir plantation, a thinning intensity of 40%-50% was proposed to be suitable, and it adjusts the canopy coverage to 0.6-0.7.

[Objective] Exploring the relationship between geographical distributions of tree species and climatic factors, and predicting their suitable distribution area are essential steps for assessing the impact of climate change on forests and for providing a theoretical basis for developing adaptive forest management strategies.[Method]Based on the forest inventory data of Hebei Province, three tree species including Larix principis-rupprechtii, Quercus mongolica and Pinus tabulaeformis were selected. Ten climatic factors related to precipitation and temperature for current and two future periods (2040-2069 and 2070-2099) were achieved using a high-resolution climate model, i.e., ClimateAP. Moreover, the ecological niche model (MaxEnt) and three climate change scenarios (the lowest, moderate, and highest greenhouse gas emission scenarios:RCP2.6, RCP4.5, and RCP8.5) were applied to predict the consensual suitable distribution area of the three tree species in current and two future periods. Response curves method was used to analyze the influence of major climatic factors on the suitable distribution area of the three tree species.[Result]Results showed that the area under the receiver operating characteristics curves (AUC) for all the studied three tree species were more than 0.85, indicating MaxEnt model had a highly predictive performance. Currently these tree species were mainly distributed in the regions of Yanshan and Taihang Mountains in Hebei Province. The main climatic factors affecting the potential distribution of the three tree species were different. Larix principis-rupprechtii was mainly affected by the accumulative temperature below 0℃ and the mean precipitation of wet quarter; while Quercus mongolica was mainly influenced by the mean temperature of the warmest month. Hargreaves climatic moisture deficit and mean precipitation of wet quarter; and Pinus tabulaeformis was mainly affected by the mean temperature of the warmest month, the mean precipitation of wet quarter, the accumulative temperature above 5℃ and the mean annual temperature. Consensus projections for 2040-2069 indicated suitable areas for Larix principis-rupprechtii and Pinus tabulaeformis would substantially expand and decrease, respectively; while Quercus mongolica would remain relatively stable. Consensus projections for 2070-2099 indicated that suitable climate habitats for all these tree species would reduce significantly and the reduction range would exceed 3% in Hebei Province.[Conclusion]The results confirmed that the geographical distribution of these tree species might change under changing climate in the future. All these tree species showed an upward shift in elevation of the projected distribution, whilst no clear shift in latitude and longitude in the two future periods. Reforestation and afforestation could be an option in adaptive forest resource management to assist these species in expanding their migration to new suitable areas in the future. The above-mentioned adaptive strategy might be useful for improving forest productivity and maintaining a healthy forest ecosystem.

[Objective]To provide a theoretical basis for further development and utilization of the Thuja's resources, the composition and relative content of chemical constituents of essential oils from leaves of Thuja plicata and Thuja occidentalis from different provenances were analyzed.[Method]The healthy 2-year-old seedlings with same size and consistent growth were selected as study materials. The volatile components of new leavesin the same position of seedlings from different provenances were extracted by solid-phase micro-extraction(SPME),and separated and identified by gas chromatography-mass spectrometry (GC-MS). Qualitative analysis was carried out by mass spectrometry and the relative content of volatile components was calculatedby peak area normalization.[Result]A total of 156 chemical components of essential oils of T.plicata and T.occdentalis were identified, among which 74 components were identified in T.plicata, and95 components in T.occdentalis. The volatile components of the two species from 10 provenances were dominated by monoterpenes, and the average relative content of T.plicata (80.258%) was higher than that of T.occdentalis (69.445%), but not forthe sesquiterpenoidsand other terpenoids.The two specieswere significantly differentin the composition of the essential oil. For example, 27 components were uniquely obtainedfrom 5 T.plicata provenancesand 35 components from 5 T.occdentalis provenances. There were only 6 common components in 10 provenances and their contents were significantly different The common components wereα-Thujone, γ-Terpinene, (8β,13β)-13-methyl-17-Norkaur-15-ene, α,α-4-trimethyl-3-cyclohexene-1-methanol acetate, Caryophyllene and Hexadecanoic acidmethyl ester, respectively.The main components ofthe essential oildiffered obviously betweentwo species. The same main componentswere only thujone and β-phellandrene whichcontents were the highestinT.plicata and T.occdentalis.[Conclusion]The chemical compositionand content of essential oils from leaves of T.plicata and T.occdentalis in different provenances weresignificantlydifferent, but the content of thujone was the highest in both species.

[Objective]Stem photosynthesis plays an important role in growth, defense, reproduction and survival for woody plant, especially for deciduous trees. In this study, we investigate dradical heterogeneity and tissue specificity of chloroplast photochemical characteristics in branches, which can provide a basis for quantifying the contribution of different tissue to stem photosynthesis, and alsolay a foundation for revealing the adaptation mechanism of chloroplast to the heterogeneous light environment in twigs.[Methods]The CO₂ release rates of current-year twigs of Salix matsudana clones were measured under light and dark conditions, and the contribution of stem photosynthesis to carbon recycle was evaluated. Besides, the photosynthetic pigment content, light absorption coefficient, photochemical efficiency and electron transport rate of bark, xylem and pith were determined, and the differences inphotochemical characteristics of chloroplasts between distinct tissues were analyzed.[Results]When exposed to the saturation light intensity, the stem photosynthesis rate of twig was 1.27 μmolCO₂·m^-2s^-1, which was able to recover and fix 77% of the carbon consumed by respiration. In the internal of twig, the total chlorophyll content of bark was highest, and was15.90 and 1.83 times higher than that of xylem and pith, respectively.The ratio of chlorophyll b to chlorophylla increased from bark to pith with the increase of radial depth. The carotenoid content and the ratio of carotenoid to chlorophyll in bark were significantly higher than those in xylem.The absorptivity coefficient of different tissues of the current-year-old branches significantly decreased along the radial direction.The maximum photochemical efficiency, effectively photochemical efficiency and relative electrontransport rate of PSⅡ of bark were significantly higher than xylem and pith.[Conclusion]Stem photosynthesis in current-year-old twigs of Salix matsudana was able to recover and fix 77% of the carbon consumed byrespiration. The photosynthetic pigment content and photochemical efficiency of chloroplasts decreased significantly with the increase of radial depth.Barkchlorenchyma was the major contributor to stem photosynthesis,and had a stronger capacity for quenching excess excitation energy. Xylem and pith chloroplasts maximized the limited light energy in the tissue by regulating the proportion of photosynthetic pigments.

[Objective] The nrDNA and cpDNA were used to determine the genetic differentiation between Haloxylon ammodendron and H. persicum, two species with sympatric distribution in China. The species discrimination ability of each single fragment and its combination of two genes was compared. In addition, we investigated the degree of ecological niche divergence and its impact on species evolution. Our study could provide important basic information for the understanding of phylogeny and phylogeography of H. ammodendron and H. persicum.[Method] We sampled 30 H. ammodendron and H. persicum individuals from the southern Gurbantunggut Desert. We performed sequence analyses using two nuclear gene sequences (ITS2, ITS1-ITS4) and three cpDNA non-coding regions (trnS-trnG, rps4 and trnV). The distance method (based on Kimura 2-parameter model) was used to analyze genetic differentiation of the two species. Bayesian method were employed to explore molecular phylogeny among individuals. Four method (genetic distances, phylogenetic trees, BLAST, and character-based method) were employed to examine the species discrimination ability of each single fragment and its combination of two genes. On this basis, we used ecological niche analysis software to calculate the ecological niche divergence of H. ammodendron and H. persicum.[Result] 1) For H. ammodendron and H. persicum, the total length of the two combined ITS sequences was all 1 117 bp, the average content of G + C was 34.74% and 34.82%, and the number of information sites accounted for 2.33% and 1.43%, respectively. The total length of the three combined cpDNA non-coding regions are all 2 344 bp, and the average content of G + C was 59.62% and 59.39%, and information sites accounted for 0.68% and 0.43%, respectively. 2) Two distinct clades of H. ammodendron and H. persicum was detected in the two phylogenetic trees. 3)Based on ITS and cpDNA sequences, the minimum interspecific genetic distance of the two species was greater than the maximum intraspecific genetic distance, and an obvious interspecific and intraspecific barcoding gap was found. The sequences combination of ITS and cpDNA can therefore be used as DNA barcode for identification of H. ammodendron and H. persicum. 4) Regarding the species discrimination rate, as calculated by the four method showed:the rate of each single ITS fragment and its combination was all 100%; for trnS-trnG, trnV and its combination, the rate was all 100%; for rps4 and its combination of trnS-trnG or trnV, the identification rate was all 0%. The sequence combinations of trnS-trnG+trnV+rps4 was 100%. 5) The observed values of ecological niche parameters (D-value and I-value) and the simulated values of the identity test were concentrated around 0.65 and 0.90 respectively, indicating a similar ecological niche in H. ammodendron and H. persicum.[Conclusion] Using ITS and cpDNA sequences, we revealed a clear genetic differentiation and molecular phylogeny relationship between individuals of H. ammodendron and H. persicum. Both the ITS and cpDNA sequence combinations could be used as DNA barcode sequences to identify H. ammodendron and H. persicum. There was no evidence for an ecological niche differentiation between H. ammodendron and H. persicum, and ecological factors did not play a significant role in the divergence and evolution of the two species, and the two species were likely to have similar evolutionary history. The conclusion of this study provide an important theoretical basis and data support for studying the phylogenetics, genetics and evolution of H. ammodendron and H. persicum.

[Objective] The NAC transcription factors are one of the largest families of plant-specific transcription factors, widely involved in plant growth and development process, and it plays a crucial role in the process responding to salt, drought and many other abiotic stresses. In present study, we cloned a NAC transcription factors gene from halophyte woody plant Tamarix hispida, to study its salt tolerance and drought resistance function in order to lay a theoretical foundation for studying the molecular mechanism of resistance to woody plant NAC transcription factors.[Method] A NAC transcription factor gene was isolated from NaHCO₃ stress transcriptome database of T. hispida, and it was named as ThNAC24 (GenBank number:KF031949). Bioinformatics tools were used to perform multiple sequence alignment and phylogenetic analysis of NAC proteins from nine other species and 105 NAC proteins in Arabidopsis thaliana were analyzed. The T. hispida samples were treated with 300 mmol·L^-1 NaCl and 400 mmol·L^-1 Mannitol respectively, and the root and leaf tissues were taken at 6, 12, 24 and 48 h after the stress. The real-time fluorescent quantitative RT-PCR (qRT-PCR) was used to analyze the expression of ThNAC24 gene under salt or drought stress in different time and tissues. It was initially identified whether it responded to salt or drought stress. To further study the stress resistance function of ThNAC24, overexpression (pROKⅡ-ThNAC24) and inhibitory expression vectors (pFGC5941-ThNAC24) were constructed. Overexpression (OE), inhibitory expression (IE) and control T. hispida plants were obtained by Agrobacterium-mediated high-efficient transient transformation system. The DAB, NBT staining, POD activity, SOD activity, electrolyte leakage, water loss rate, and MDA content under salt and drought stress were measured and compared with the transgenic T. hispida to identify the salt tolerance and drought resistance of the ThNAC24 gene.[Result] The open reading frame of ThNAC24 gene is 1 023 bp, encoding 340 amino acids. Multiple sequence alignments results show that the amino acid sequence of ThNAC24 is relatively high in the N-terminal and has the sequence characteristics of NAC family. Phylogenetic tree analysis showed that ThNAC24 was closely related to ANAC103 and ANAC082. The result of qRT-PCR showed that the expression of ThNAC24 gene was up-regulated under salt or drought stress. The expression level of ThNAC24 was the highest at 12 h in root tissue, while it was the highest at 24 h in leaf tissue; Under drought stress, the expression level was the highest at 6 h in root tissue, while it was the highest at 12 h in leaf tissue. The ThNAC24 gene was expressed in roots and leaves of T. hispida and responded to salt and drought stress. Overexpression of the ThNAC24 significantly reduced the contents of H₂O₂ and superoxide anion, enhanced the POD and SOD activities in T. hispida, thus decreased ROS accumulation. Overexpression of the ThNAC24 gene can reduce the electrolyte leakage, water loss rate and MDA accumulation of T. hispida under stress, thus protecting the integrity of cell membrane structure.[Conclusion] The ThNAC24 gene can respond to salt and drought stress. Overexpression of the ThNAC24 gene significantly enhances POD and SOD activities to improve ROS scavenging, reduces cell damage or death of T. hispida and improves its salt tolerance and drought resistance.

[Objective] In this article, we aimed to establish large scale propagation methodologies for Liriodendron sino-americanum (hybrid Liriodendron) and to this end we investigated how various combined treatments with the plant hormones abscisic acid(ABA)and zeatin(ZT)affect its somatic embryogenesis and development.[Method] We successfully induced somatic embryos using the embryogenic callus of L. sino-americanum genotype 15-5202. We tested how adding either ABA alone or ABA and ZT together to the differentiation medium affected somatic embryogenesis. Our differentiation medium induced somatic embryos with a high frequency and was screened by counting the number of somatic embryos and observing their growth and development.[Result] 1) The addition of ABA to the medium showed positive effect on the induction and maturation of somatic embryos. 0.5-1.5 mg·L^-1 ABA in the medium accelerated the development of somatic embryos with largely normal morphology. When adding 2.0-2.5 mg·L^-1 ABA, the differentiation rate of somatic embryos increased significantly, but the proportion of abnormal embryos increased. After 30 days of treatment with low-concentration ABA, somatic embryos matured with an additional 2 weeks of culture in light. By contrast, on medium without ABA, somatic embryos were white and not fully matured with pale yellow cotyledon. 2) Adding ABA together with ZT to the medium significantly increased the differentiation rate and development of somatic embryos. Treatment with 2.0 mg·L^-1 ABA combined with 0.2-0.4 mg·L^-1 ZT induced somatic embryos with normal morphology, clearly showing green cotyledons and a radicle after 2 weeks light culture, while the growth and development of somatic embryos was noticeably slower without ZT treatment. Adding ZT concentration of higher than 0.6 mg·L^-1 inhibited growth and development of somatic embryos and was unfavorable to their induction and maturation.[Conclusion] A differentiation medium containing 2.0 mg·L^-1 ABA and 0.2-0.4 mg·L^-1 ZT, significantly increases the efficiency of L. sino-americanum somatic embryogenesis and promotes normal development of somatic embryos.

[Objective]It is important to analyze the relationship between tree mortality and planting density, competition, site index, and climate factors for managing Chinese fir(Cunninghamia lanceolata)well.[Method] Based on the Chinese fir data in Jiangxi Province, three widely used model for analyzing binary data which are logit, probit and cloglog link models were used to modelling tree mortality and compared with each other. Then we introduced the plot and tree random effects to the selected model in order.[Result] The result showed that the logit model was the best(AIC=4 700.419), followed by probit model, and cloglog model. Also accounting for the plot and tree random effects at the same time had the best performance, and its AUC was 0.966 8, which was close to 1. In addition, we also found:mortality rate increased with increasing initial planting density and site index; decreased with increasing d/D_g; decreased with increasing mean annual temperature and previous summer mean temperature; increased with increasing previous winter mean minimum temperature and annual heat-moisture index.[Conclusion] Logit model performed well on modeling tree mortality in relation to planting density, competition, site index, and climate factors. The research of relationship between mortality and annual heat-moisture index could be helpful for managing Chinese fir plantations under the climate change.

[Objective] Forest disturbance is the main factor that influences forest height. This study was aimed to extract forest disturbance parameter based on remote sensing image and to know its effect on forest height estimation.[Method] Liangshui National Nature Reserve in Dailing District, Heilongjiang Province, China, was selected as study area, thirty-three periods of Landsat thematic mapper and enhanced thematic mapper plus(Landsat TM/ETM+) multispectral data from 1984 to 2006 in Liangshui National Nature Reserve were acquired as data sources. The tasseled cap transform was conducted to extracttwo disturbance monitoring indices of the tasseled cap angle(TCA)and tasseled cap distance(TCD). Time trajectory analysis method Landsat-based detection of trends in disturbance and recovery(LandTrendr) was applied to conduct time series reconstruction of the Landsat TCA(TCD) images and extract timeseries disturbance parameters of forest:previous year prior to disturbance onset(DBYEA), spectral value prior to disturbance onset(DBVAL), disturbance duration(DDUR), disturbance magnitude(DMAG), time to start recovery after disturbance(RBYEAR), spectral value for recovery start after disturbance(RBVAL), recovery magnitude(RMAG), recovery duration(RDUR).Two sets of spectral information variables of single-temporal Landsat image with or without time-series disturbance parameters were applied to estimate forest height by using random forest algorithm.[Result] Compared withthe tree height inversion model based on the spectral information of single-temporal Landsat image, the prediction accuracy of the tree height inversion model according tocombination of the spectral information of single-temporal Landsat image with 16 time-series perturbation parameters based on TCA and TCD increased by 6.34%, and the RMSE decreased by 0.5 m. In the tree height inversion model, the time-series perturbation parameters based on TCA extraction were more important than those based on TCD extraction.[Conclusion] Time-series disturbance information of forest extracted based on LandTrendr method could enhance the correlation between reflectance and tree height, and could also improve the prediction accuracy of the tree height model based on remote sensing. Time-series perturbation parameters based on TCA extraction is better than those based on TCD extraction to interpret forest height estimation. The method can be used as a reference for remote sensing inversion of forest parameters(e.g., tree height and biomass).

[Objective] Monitoring bamboo forest resources and their changes using time series remote sensing has a great significance in achieving scientific management and efficient utilization of bamboo forest resources.[Method] This study extracted the information and analyzed spatiotemporal evolution of bamboo forest based on the Landsat5 TM and Landsat8 OLI time series data in 2000, 2004, 2008, and 2014 throughout Zhejiang Province to reveal the change of bamboo forest area and its response to land use change.Firstly, the land utilization information and spatiotemporal distribution of bamboo forest was extracted by maximum likelihood classification based on time series Landsat data, which was preprocessed by atmospheric correction and geometric correction. Secondly, the spatiotemporal evolution of bamboo forest during 2000-2014 using two indexes (variation amplitude and dynamic degree). Finally, the relationship between spatiotemporal dynamic of bamboo forest and land utilization pattern was analyzed based on the established provincial land use transition matrix.[Result] The result showed that:1) The extracted bamboo forest information based on time series Landsat data achieved a high accuracy, which yield more than 75% of classification accuracy and 91% of user's accuracy, and the extracted bamboo forest area was highly correlated with investigation data, with area accuracy of beyond 96%. 2) The bamboo forest in Zhejiang Province was increased from 2000 to 2014, the variation amplitude and annual change rate were 16.55% and 1.18% respectively. 3) The bamboo forest area accounted for 7.33% in 2000, and increased to 8.56% in 2014, wherein the land use change of coniferous forest, broad-leaved forest and cultivated land have a great contribution to the increased of bamboo forest area, with the contribution rate of 28.62%,37.23% and 16.15%, respectively.[Conclusion] The bamboo forest resources could be accurately monitored based on the Landsat time series data, and the decreasing of coniferous forest, broad-leaved forest and cultivated land has significant influences on the spatiotemporal evolution of bamboo forest.

[Objective] In the present work we studied the characteristics of the interception of the radiant heat flux by two typical wildland combustibles and the associated ignition phenomena during the spread of a wildland fire through theoretical calculation, based on the principle of radiant heat transfer and fire behavior model.[Method] Thermal radiation was sourced from the burning zone in a forest fire, which was considered as an equivalent rectangular emissive surface. The length of the emissive surface corresponded to the flame length, whereas the width was determined by the fireline size; The rectangular emissive surface had a tilted angle varying with the environmental wind speed. Two typical combustibles around the edge of a forest, i.e. the dead standing timbers and the dead fallen timbers, were selected as the thermal attack targets with the receiver elements set at 1.5 m high above the ground and on the ground, respectively. By taking into account of the radiation heat exchange during the fire spread and the fire extinction process of the fire at the edge of a forest, a mathematical model was developed to quantify the transient rate of heat exchange between the flame zone and a target at the forest edge and then the accumulated amount of radiation heat intercepted by the target during a fire. Meanwhile, in combination with the existing understanding on forest fire behavior, the formulas were also derived to correlate the parameters of the fire behavior presented during fire spread and the fire extinction process, which enabled the proceeding of the thermal radiation transfer calculations and the evaluation of ignition conditions for various fire scenarios. In light of the principle of fire safety assessment with effectiveness, the worst fire scenario was considered during evaluation, where the flame had a temperature of 1 200 K and an emissivity of 1.0, and the atmospheric transmittance for thermal radiation was set at 1.0 as well. Furthermore, the flame width was evaluated at 50 m, and the flame length was ranged from 5 m to 40 m, whereas the wind speed varied from 0 m·s^-1 to 10 m·s^-1 to simulate drastic change of the environmental conditions.[Result] The calculations for specific fire situations were performed and then compared with the available field test results. It was observed that the calculated radiant heat flux coincides with the field measurements, which confirmed the reliability of the model for determining the radiant heat transfer in forest fire. The examination of various practical fire scenarios indicated that a dead standing timber near the forest edge takes the advantage of both intercepting radiant heat flux and accumulation of radiation heat in comparison with a dead fallen timber as a rule, although this advantage is weaken with an increase in the environmental wind speed. The radiant heat flux received by individual targets reaches the maximum just after a fire source arrives at the forest edge, and the energy accumulation by a target at this stage plays a major role in the ignition of the target.[Conclusion] With the increase in the distance between the set target and the forest edge, the levels of energy accumulation by the target decreased rapidly; meanwhile, the ignition of a target was altered by the flame length and the local wind speed owing to their roles in the change in the duration of thermal radiation and the radiant heat transfer efficiency between fire source and the target. A large amount of calculation results for the dead standing timber near the forest edge suggested that, a non-fuel interval with a width of above 30 m is sufficient to avoid the ignition triggered by thermal radiation from a forest fire with the flame length up to 40 m. However, in case of construction of a biological fire-prevention belt, the separation distance can be reduced to a large extent. This work provides a specific theoretical guideline for the design of forest fire barriers in forest areas as well as the protection of structures and facilities in wildland fire-prone areas.

[Objective]The pine caterpillar, Dendrolimus tabulaeformis (Lepidoptera:Lasiocampidae) is a serious defoliator in the stands of Pinus tabulaeformis in China. In this study, a multi-factor disaster risk assessment method is proposed for prevention and early warning before the pest disaster, which is based on climate, topography and other factors that affect disaster occurrence and disaster grade.[Method] The distribution range of P. tabulaeformis was extracted from Landsat data in Western Liaoning Province. The eight risk assessment factors, including elevation, aspect, slope, rainfall, accumulated temperature, sunshine hours, disaster degree in the previous year and the distance from the disaster area in the previous year, were collected, and then the weight of each factor was determined by analytic hierarchy process. Finally, a weighted information model was established. Combining with the spatial analysis method of GIS, the disaster risk of P. tabulaeformis was classified into five levels:extremely low-risk area, low-risk area, medium-risk area, high-risk area and extremely high-risk area. A hazard zone map was made with the above information and the accuracy is verified by comparing with the monitoring result of actual disaster degree.[Result] 1) According to the principle of information quantity method, the greater the amount of information, the greater the risk of disaster. The information values of each factor classification calculated in this paper coincided with the biological characteristics of D. tabulaeformis. 2) The mapping results showed that in 2017 high-risk area and the extremely high-area in the study area was mainly distributed in the northern part of Jianping county. Medium-risk areas were mainly located in the northern part of Jianping County and the interchange between Jianping and Lingyuan. The risk of the insect pest in other areas was low. The mapping results were consistent with the actual survey results. 3) The relationship between the finally classified middle-low risk areas and the actual defoliation rate of P. tabulaeformis is obvious. Around 90.32% of the actual infested P. tabulaeformis forests are classified into high risk areas and extremely high areas.[Conclusion]Based on the weighted information model, the risk assessment of pine caterpillar disaster comprehensively considers the difference of the impact of different evaluation factors on the disaster occurrence. The result of risk zoning is accurate and has certain application value. It can provide technical basis for the risk assessment of forest pests and diseases in large areas.

[Objective] This research aimed to provide reference for the protection of the isolated wildlife population of Chinese goral (Naemorhedus griseus) by using the Population Viability Analysis (PVA).[Method] The updated Vortex package was used to make a simulation analysis on population viability of a closed Chinese goral group based on 10 years field monitoring data on the Chinese goral population at Inner Mongolia Saihanwala nature reserve. The simulation referred to the data of population size, mating system, environmental capacity, genetic diversity, catastrophes frequency, and information collected from other populations of the goral species.[Result] The result indicated that the survival probability of this population would be 0.33 in the next 100 years if no translocation occurred. Additionally, sex ratio at birth, mortality of infant females and the mortality of adult females would seemingly play crucial roles in determining persistence by the sensitivity analysis. If a translocation (supplementation with one female and one male adult every three years) can be ensured, the Chinese goral population in the study area will grow steadily, without risk of extinction.[Conclusion] Population viability for this isolated Chinese goral group is not optimistic. A supplementation by extra goral individuals would be the most effective measure for stable population growth. Supplementation of feedings and nutrient salt in harsh winter is also an important measure to improve individual survival and breeding conditions in maintaining present population.

[Objective] To improve the performance and reduce the costs, the poly(3-hydroxybutyrate-co-4-hydroxybutyrate)(P34HB)was reinforced with wood flour. The optimum ratio of wood flour was determined by experimental research.[Method] Using Chinese white poplar(Populus tomentosa)flours and P34HB as raw materials, the biodegradability composites were prepared by hot pressing method. The structure and properties of the biodegradability composites were characterized by scanning electron microscopy(SEM), differential scanning calorimetry(DSC), thermal gravimetric analysis(TGA), Fourier transform infrared spectroscopy(FTIR),dynamic mechanical analysis(DMA)and mechanical property analysis.[Result] Results show that the tensile strength, breaking elongation and flexural strength of the composite increase firstly and then decrease with the increasing of wood flour, but the impact strength decreases continuously. The tensile strength, elastic modulus and Young's modulus of the composites increase by 89%, 59% and 103%, respectively. The storage modulus E' of the composites is continual increasing with the wood flour content, while the tanδ is decreasing initially and then increasing. The dynamic stiffness of the composite is better than static stiffness,for the higher frequency modulus is greater than the lowerone.Compared with P34HB, the composites show the wider thermal decomposition range, the slower pyrolysis rate and the higher pyrolysis residual mass.[Conclusion] With the increase of wood flour content, the structure of the composites is further dense. The storage modulus and brittleness of the composites increase because of hindering the movement of the molecular chain of bioplastics P34HB by wood flour. At the same time, the transcrystallinity of P34HB with high crystallinity and developed layer structure is developed bywood fibers as nucleating agents,strengthening the interfacial bonding strength between wood flour and P34HB, and obviously improving the mechanical properties and thermal stability of the composites. It is also found that the optimum wood flour content of P34HB/wood flour composite is 50%.

[Objective] In order to produce the whole bamboo veneer with equal and continuous thickness, reducethe limitation of material selection by bamboo no-card axis rotary cutting machine, expandthe application range of rotary cutting equipment, and improvethe overall turnout percentage and yield rate of bamboo rotary cutting, in this paper, a mathematical model of a new rotary cutting curve based on "logarithmic spiral" is proposed, and the theoretical turnoutrate of bamboo veneer is calculated. The fitness of established model for the use of the no-card axis bamboo rotary cutting machine was also analyzed.[Method] Mathematical model of the two rotary cutting curves were built.Then the mathematical model of the traditional no-card axis rotary cutting theory "Archimedes spiral" and the improved mathematical model of the rotary cutting curve (elliptical "logarithmic spiral" curve) was simulated and analyzed by using Matlab. Finally, the three-dimensional model of the bamboo segment to be processed is established. Combined with the simulation result of Matlab, the formula of the bamboo cutting yield rate is deduced, and the mathematical formula for calculating the yield rate is obtained.[Result] According to the simulation result of Matlab, the "Archimedean spiral" is a circular spiral. Since the cross section of the bamboo is irregular and approximately elliptical, the wall is thin, and after being rounded, the machining margin of the bamboo wall-thickness becomes smaller, the circular spiral curve is not completely suitable for the processing of natural growth bamboo,and defects such as fragile and irregular shape of the processed bamboo veneer occured.The improved "logarithmic spiral"shows the elliptical curve and the cutting curve is similar to the actual shape of the bamboo, which can ensure that the accuracy of the adjacent spiral distance error is within the allowable range, and the model is more suitable for the rotary cutting of the bamboo veneer. The mathematical model parameters can be adjusted in real time according to the size of the inner and outer diameter of the bamboo during processing, which reduces the limitations of bamboo selection.Through the mathematical model analysis of the turnout percentage, it is concluded that the turnout percentage(η) of bamboo is independent of the length (L) of the bamboo segment, and the influence of length, wall thickness and sharpness are analyzed, which can provide reference and theoretical basisfor actual processing and production.[Conclusion] The improved mathematical model of the rotary cutting curve is based on the "logarithmic spiral". When the bamboo is rotated, the thickness error of the veneer is small, the rotary cutting efficiency is high, and the reliability and processing precision are also high. Under the premise of meeting the processing requirements, in order to ensure the bamboo material yield rate, rotary cutting efficiency, rotary cutting quality and other specific requirements, the length of the processed bamboo segment L is required to be about 0.8-1 m. The wall thickness of the bamboo is more than 10 mm, and the sharpness is less than 3-4 mm·m^-1. The establishment of the new rotary cutting model has improved the overall utilization rate of bamboo and broadened the processing range. It provides a basic theory for the design of bamboo rotary cutting equipment, and proposes a new development direction for the bamboo cutting processing without card shaft.

Although a nest box has been widely used as artificial tree-cavity over the world for more than a century, the actual utility is unsatisfactory due to the inside temperature and durable life of nest box or other reasons. We suggest that the future artificial tree-cavity design should be closer to the natural tree-cavity, a curved exterior structure should be used to uniformly obtain solar radiation evenly and reduce wind resistance; Modular components should be used to meet the needs of different functional components for different attracting species; High strength, non-hydrophilic, UV-resistant, weather-proof, and fireproof materials are recommended for the exterior of artificial tree-cavity. The plastic lightweight material with low thermal conductivity are recommended to be used as the core of artificial tree-cavity; A fixed method which can compensate the radial variation of trunk should be used; A top anti-collision facility is recommended to be added to reduce the damage of falling branches; Living climbing plants used as fixing materials may increase attachment life; A non-destructive fixation method is recommended to connect the artificial tree-cavity with the carrier; The back plate structure with high friction force is to designed to reduce the force on the attachment equipment by increasing the friction with the attachment, so as to extend its service life; A solar powered micro-heating device should be used to improve the thermal efficiency of the overwintering nest; A mobile communication signal receiver and the corresponding program can be used to control the nest box surface color or solar reflection and vent to meet with the demand of thermal physiology of the target species in different seasons by remote control; The newly designed artificial tree-cavity should be put into use in the field after passing the fatigue test and the weather resistance test, and should to further modify the design of various influencing factors according to the feedback field continuous monitoring data; The principle and knowledge of fluid mechanics, materials science, architectural environment science and design art should be used to further improve the design of artificial tree-cavity.

Fiber saturation point(FSP)is an important concept in the field of wood science which was first proposed by Tiemann in 1906 and has been discussed in the literature for over 100 years. FSP has played an important role in wood-water relations, wood physical and mechanical properties and other research fields in wood science. Despite its importance and extensive study, the exact theoretical definition of the FSP and the correct way to measure the FSP are still debated because considerable progress has been made compared with the initial concept form of FSP. The research on wood-water relations has changed from qualitative description of the state and its locations of water in wood to the direction of water potential differences and water phase boundaries, and relevant new theoretical definitions and test methods of FSP have been presented in recent years. The research on FSP is relatively lagging behind in our country, there are rarely introductions to principles and test methods of FSP. In this paper, the development of FSP concept has been summarized, the advantages and disadvantages of test methods are analyzed systematically. The applications and further developments in wood-water relations, wood drying technology, modification effect are also summarized. According to the different research stages of wood-water relations, the concept of FSP could be divided into 4 types. The first type emphasizes that FSP could be defined from physical and mechanical properties, or locations of water in wood. The second type concept related FSP to the amount of water contained with the water saturated cell wall. The third type concept emphasizes the different combination forms between water and wood, which could result in different thermal phenomenon. The fourth type concept of FSP is based on solution thermodynamics that treats the FSP as a phase boundary, which attaching clear physical meaning to FSP. The test methods of FSP could be divided into 7 types, including extrapolation method, solute exclusion method,pressure plate measurement, differential scanning calorimetry method, centrifugal dehydration method, nuclear magnetic resonance method, and solution thermodynamics calculation method. The actual bound water content in cell wall could be determined from these methods except for extrapolation and solution thermodynamics calculation method. The actual bound water content is obviously higher than 30% which is traditionally considered as average value of FSP. The research on FSP could further play an important role in the analysis of shrinkage and swelling, working out wood drying schedule. It also could be applied in the evaluation of wood modification effect and the microstructure analysis after modification treatment. The chemical potentials expression of the wood-water relationship and wood moisture phase diagram based on the FSP thermodynamic concept would be an important research field of wood-water relations scientific evaluation system, and more attention should be paid in wood science and industry.

Ecological protection of mountainous areas and rural poverty alleviation are important policies in developing countries,study on rural geography and ecological protection should be paid more attention to the effect of ecological protection of mountainous areas on livelihoods of local community residents. Based on the review of the related literature at home and abroad,the impacts of ecological protection on livelihood capital of community residents, livelihood strategem of community residents and livelihood result of community residents are systematically summarized,and how the ecological protection affects livelihood of community residents is also revealed. Finally,the co-author propose a research field,according to the current situation of the research and practice,the influential processes and mechanisms of the impacts of ecological compensation on community residents sustainable livelihoods are the key issues in the future which need to be paied more attention to,we also should further explore the sustainable livelihoods of community residents of cological protection area,strengthen the application of new techniques and method in the research about the sustainable livelihoods of community residents.

[Objective] This paper analyzes the value, market demand and prospect development of Xiangfeng peony, and provides certain reference for introducing and popularizing this new variety, so as to promote the healthy development of Xiangfeng peony and oil peony enterprises and to ensure the sustainable development of oil peony industry.[Method] On the basis of existing research, the economic benefit evaluation index system of oil peony varieties, including yield per unit area, income per unit area, field management cost, investment recovery period, the increase rate of per capita income of planting farmers five evaluation indexes, is constructed. By determining the index weight based on AHP (analytic hierarchy process) in combination with Yaahp11.1 software and establishing the comprehensive benefit evaluation model with the fuzzy comprehensive evaluation method, this paper takes "Fengdan" original high quality varieties as control group, the economic benefit and evaluation of the original varieties of peony and "Xiangfeng" were analyzed.[Result] The result of this study indicated that the economic benefit evaluation result of "Xiangfeng" is "good", and the result of the economic benefit of "Fengdan" is "general". In terms of the yield per unit area, "Xiangfeng" compared with the original "Fengdan", and the yield per hectare increased by nearly 750 kg, which increased by 126.84%. In terms of the income per unit area, "Xiangfeng" increased its income per hectare by about 22 500 yuan. In the field management fee, "Xiangfeng" in the field management cost index is slightly lower than that of original "Fengdan"; In the investment recovery period, "Xiangfeng" can make both ends meet in the third year after planting, as early as one year in "Fengdan". This indicates that the new variety of "Xiangfeng" has been improved in economic efficiency, and its economic benefit is better than that of "Fengdan"[Conclusion] Compared with control group,the original varieties "Fengdan", "Xiangfeng" has good economic benefit. It has a positive impetus to the development of regional economy and farmers' incomes, the future development trend is good, the development potential is larger. The introduction of the new species will bring more economic benefits and profits. Therefore, the new variety of "Xiangfeng" has the value and potential of being widely promoted by enterprises and farmers.

[Objective] The mean water use efficiency (WUE) of different vegetation types were compared in Central Asia. Based on this, the altitudinal and latitudinal distribution of WUE were characterized, and the variation trend of WUE within and among the years were analyzed, in order to revealfrom a macro perspective the temporal and spatial variation of WUE in different vegetation types in Central Asia.[Methods]The land cover data was used to integrate different vegetation type classifications, and the MODIS product data primary productivity (GPP) and evapotranspiration (ET) were used to calculate the monthly average and annual average WUE, the WUE changes at different altitudes and latitudes were observed.[Results]1) The lower GPP ecosystem has higher WUE, and vice versa. The WUEs of different vegetation types were ranked in the order:open shrub land > grassland > closed shrub land > forest > cropland, the open shrub land WUE was significantly greater than those of the other vegetation types (P<0.05). The WUE of different vegetation types varied strongly with the altitude:it appeared relatively constant as the altitude varies from 0 to 1 200 m and then decreased dramatically above 1 200 m. The high WUEs appeared in farmland, forest, closed shrub land, open shrub land, grassland at altitudes of 750, 750, 750, 1 250, and 500 m, respectively. WUE exhibits large variability with latitude. The peak WUE appeared at latitude of is 36(farmland), 32(close shrub land), 36-38(open shrub land), 50(forest), 32(grassland) respectively. From 2000 to 2014, the average WUE was 2.65 g·kg^-1 in Central Asia, and tended to increase as an overall trend. The annual increase was 0.066 g·kg^-1; the monthly variation of WUE appeared increase first followed by a decrease, this can be well described by a one-dimensional cubic function.[Conclusion]With the increase of altitude, WUE showed a trend of increase first and then followed by a decrease. The WUE of different vegetation types showed different trends with the increase of latitude, and an upward trend from 2000 to 2014.

[Objective]In this study, effects of leaf types on growth and chlorophyll fluorescence characteristicsin Pinus massoniana seedlings were studied in order to provide scientific basis for selection and cultivation.[Method]One-year-old seedlings of P.massoniana have three different leaf types, such as primary needles, needles and intermediate type, at nursery stage. In this experiment,the growth traits, photosynthetic pigment contents and chlorophyll fluorescence parameters were investigated on one-year-old seedlings of P.massoniana. The chlorophyll fluorescence characteristics of primary and secondary leaves and their effects on seedling growth were studied.[Result]The results showed thatthequality index (QI) at nursery stage, dry matter accumulationand growth traits one year after afforestation of the seedlings with needle swere significantly better than those with primary needles. The leaf length,volume and surface area of needles were significantly larger than the primary needles. Contents of chlorophyll a, chlorophyll b and total chlorophyll in primary needles were much higher than those in needles, while there was no significant difference in the content of carotenoid between the two types of needles. For chlorophyll fluorescence parameters, the F_m, F_v/F_m and F_v/F_o in primary needles were significant higher than thosein needles.There was no significant difference in F_o between the two leaf types.The Y(Ⅱ) and F_v'/F_m' of PSⅡreaction center,q_P and NPQ of quenching parameter, Y(NPQ) and Y(NO) of energy dissipation and the photoresponse parameters, such as ETR_max,α,β and I_k in primary needles were significant higher than those in needles.It was indicated that the primary needles performed much better on the content of chlorophyll and light inhibition, with higher photosynthetic efficiency than needles, while the heat dissipation and non-photochemical quenching would increase under the intensivelight. However, due to larger leaf length, volume and surface area than primary needles, the seedlings with needles were able to obtain more light for photosynthesis and hence produce more dry matter. The quality indexat nursery stage and growth after afforestation of the seedlings with needle swere higher than those of the seedlings only with primary needles.[Conclusion]The primary needles performed much better on the content of chlorophyll and light inhibition, with higher photosynthetic efficiency than needles, and the heat dissipation and non-photochemical quenching would increase under the intensive light in order to reduce the damage of excess light energy to photosynthesis system.The seedlings with needles had better seedling quality and growth characteristics.

[Objective] To reveal the formation rhythm of fatty acids in Plukenetia volubilis seeds during developmental process, and provide a scientific basis for the promotion of planting area and the breeding of new varieties, in this study the accumulation characteristics of fatty acids in the seeds of P. volubilis was studied, and the fatty acid components in the seeds at different developmental stages were analyzed.[Method] The fatty acid components of 18, 36, 54, 72 to 90 DAF seeds from mature P. volubilis plant were extracted by liquid nitrogen, and the relative content of each component and their dynamic changes were analyzed by GC-MS.[Result] The results showed that 56 chemical substances, including 14 fatty acid compounds(80.13%), 7 ester compounds(2.70%), 24 alkane compounds(12.40%), 7 benzene compounds(3.96%) and 4 other compounds(0.81%), were detected and identified from P. volubilis seed during developmental process. The fatty acid compounds mainly contained 9,12-octadecadienoic acid, 9,12,15-octadecatrienoic acid, hexadecanoic acid, octadecanoic acid, 9-octadecenoic acid and 16-methyl-heptadecanoic acid. With the increase of maturity, total content of fatty acid compounds increased gradually from 53.60%, 76.30%, 76.78%, 96.43% to 97.54%. Among them, 9,12-octadecadienoic acid, and 9,12,15-octadecatrienoic acid showed an increasing trend, while hexadecanoic acid, octadecanoic acid, 9-octadecenoic acid and 16-methyl-heptadecanoic acid showed a decreasing trend.[Conclusion] During the seed development of P. volubilis, the fatty acid components gradually changed from saturated fatty acid and monounsaturated fatty acid to polyunsaturated fatty acids. P. volubilis has the characters of shorter maturity and higher conversion efficiency of unsaturated fatty acid compared with other oil plants, which may be related to their high photosynthetic rate. Therefore, P. volubilis, as a strong light-required edible oil plant, is suitable cultivated in low latitudes region such as Guangdong, Guangxi Yunnan, Fujian, Hainan and Taiwan provinces, which could enrich oil plant resource and increase edible oil kinds in China.