Nowadays, plant functional groups (PFGs) have been recognized as a promising tool in management and restoration of degraded species-rich ecosystems. However, their potential distribution, especially in a tropical forest landscape, is rarely studied. Based on an investigation of 135 plots in a tropical natural forest landscape of Bawangling, Hainan Island, South China, the PFGs were classified by employing two criteria of successional status and potential maximum height. In this study the genetic algorithm for rule-set prediction (GARP) was used to estimate the potential distribution of the PFGs and then the receiver operating characteristics (ROC) was used to evaluate the predictive performance. Multiple linear regression analysis was applied in order to find out the major factors determining potential distributions of the PFGs. Results showed that the predictive accuracies for the eight PFGs were all over 70%. Compared with the climax functional groups, the pioneer functional groups had higher potential maximum distributional range, smaller maximum suitable range and presented more dispersed distribution pattern. This indicated there were different in autecological characteristics and responses to environment between pioneer and climax species. The analysis of correlation revealed that minimum temperature, annual mean temperature, maximum temperature, annual mean relative humidity, annual mean precipitation, aspect and elevation were the key factors determining potential distributions of PFGs. The results further also demonstrate that the GARP ecological niche model using presence-only data and large-scale environmental variables is a powerful tool for predicting species' geographic range.

Soil moisture plays an important role for forestry in the Loess Plateau. Using neutron probe, the vertical changes of soil moisture of Robinia pseudoacacia plantations grown in the semi-humid region were measured during April to October in 2004 and 2005. A compartment model and the data of the soil moisture measured in 2004 were used to set up a balance model with absorption chamber of rainfall infiltration into the soil: WC=a(e^-kh-1)+c(1-e^k₁h)+WC₀, if a>0, c>0, k₁>k>0. k₁ and k is the soil absorption rate and loss rate of rain water into soil the parameters under specific conditions reveal the different ecological environment of soil moisture of Robinia pseudoacacia plantations grown in the Loess Plateau. The model was tested and verified by using the survey data in May 2005. The result showed that the goodness of fit answered for need of statistics, and the model was able to well reflect the characters of vertical changes of the soil moisture.

Litter plays an important role in carbon flow between above ground and the soil, however there is little knowledge of relationship between litters and soil organic C under vegetation types. The objective of the present study was to quantify litter accumulation, and soil organic C in artificial and natural vegetations in the hilly region of Loess Plateau, China. A sampling grid was established from arable land, grassland, shrubland, and woodland on the Huangmian soil at the Yangou watershed. Three soil cores were collected in each sampling site. Soil samples were analyzed for organic C, dissolved C. All surface litter in 1 m×1 m area was collected prior to soil sampling, dried, weighed, and analyzed for total C and N. The litter accumulation in the natural grassland, shrubland and woodland were 5.3, 12.1 and 32.4 t·hm^-2, respectively, and the litter accumulation of artificial shrubland and woodland were just 6.7 and 11.4 t·hm^-2.The natural vegetation's litter accumulation ranged from two to five times of artificial vegetation. Except pure Robinia crop, the C/N of natural vegetation is higher than that of the artificial vegetation. SOC content in grassland was as 3.1 times as that in arable land; natural shrubland and artificial shrubland were as 5.9 and 1.8 times as arable land, respectively; natural woodland and artificial woodland were as 8.0 and 4.0 times as arable land, respectively. In addition, there was a significant correlation between litter accumulation and SOC content of the soil layer from 0 to 20 cm, however not below 20. There was a significant correlation between litter accumulation and DOC content of the soil layer from 0 to 10 cm. The litter accumulation and SOC content of the soil layer from 10 to 60 cm was not significantly correlated. A negative significant correlation was found between litter accumulation and DOC content of the soil layer from 80 to 100 cm.

The forest community stability was evaluated by calculating subordinate function values of a model which was established based on fuzzy synthetic evaluation by five indices of population regeneration，soil fertility, woodland productivity，species diversity and anthropogenic destroy in main forest communities of Huanglong Mountains. The results showed that forest community stability evaluation of main forest communities in Huanglong Mountains ranked in the decreasing order of community of Quercus liaotungensis forest，Pinus tabulaeformis+Quercus liaotungensis forest，Pinus tabulaeformis forest and Betula platyphylla forest. The result was consistent with development status of the local forest community. The selected indices of this model reflected forest community stability，and highlighted forestry data application. Whole process of evaluation in this model avoided complicated calculation， and was easy to operate. Therefore，this model is suitable for extending its application in forest community stability judgment.

By using a method of overflowing in a slope plot, a final infiltration rate on hillslopes under 4 typical vegetation forms and the influencing factors were investigated in the small watershed of Diediegou. The result showed that the final infiltration rate of different vegetation types were: natural grassland＞shrub of Ostryyopsis davidiana＞ shrub of Hippophae rhamnoides＞ plantation of Larix principis-rupprechtii. The final soil infiltration rate on different slope aspects showed shady slope ＞ semi-shady slope ＞ semi-sunny slope. The final soil infiltration rate under different slope position exhibited midst slope position ＞ lower slope position ＞ upper slope position. The final soil infiltration rate under different slope gradient showed middle slope gradient ＞steep slope ＞gentle slope. The final infiltration rate increased with rising slope gradient as the slope gradient is smaller than 25°, and decreases with slope gradient as it is higher than 25°. Based on the data, the dominant influencing factors were discovered, and the relations between infiltration rate and influencing factors were obtained by step-wise regressing analyses for the cases below or above the slope gradient to 25°.

Different clear-cutting patterns were executed in low-quality forest stands of Lesser Khingan Range in spring, summer, autumn and winter. Soil respiration of the low-quality forest stands was recorded by using a LI-8100 CO₂ flux automatic monitoring system. Influence of the clear-cutting pattern on the soil respiration and the reasons causing differences in the soil respiration with different clear-cutting patterns were investigated and analyzed with statistical analyses. The results showed that the soil respiration was the biggest in summer and the lowest in winter at the experimental area. Less difference in the soil respiration in the spring and autumn was noticed likely due to little difference in soil temperature and moisture content. Within a belt of horizontal zone, there was no significant difference in the soil respiration, and the different band widths had no remarkable influence to the soil respiration. The soil respiration along elevation in vertical clear-cutting zone fluctuated, but the overall tendency was decreasing in the soil respiration with increased altitude. The soil respiration annually released 1.184, 1.426, and 1.179 kg CO₂·m^-2a^-1 in horizontal zone,vertical zone and forest gap, respectively. Soil temperature was the key factor affecting the soil respiration in vertical zone while in forest gaps the key factor was the soil moisture. The soil temperature and moisture content in horizontal zone lied in between vertical zone and forest gap. This indicated that in the condition of different clear-cutting patterns, the key factor affecting the soil respiration was not in the same.

We examined effects of exogenous nitric oxide derived from a donor of 10～50 mg·L^-1 sodium nitroprusside (SNP) on detached leaves of Shibataea chinensis after anthesis.The results showed that: decreases of leaf chlorophyll and protein content were alleviated to different degree when the isolated leaf was pretreated with different concentrations of SNP solution, among which the 30 mg·L^-1 SNP had the best effect. Compared to control, the detached leaf SOD and POD activity were respectively decreased by 26.2% and 35.6%, maximum fluorescence of dark adaptation (F_m), PSⅡ maximal photochemical efficiency (F_v/F_m), and PSⅡ potential activity (F_v/F_o) were respectively decreased by 42.1%，38.2%，77.0%, but the minimum fluorescence of dark adaptation(F_o) was increased 89.5% after 5 d treatment. However, after the pretreatment with 30 mg·L^-1 SNP, the changes of all the above physiological parameters were inhibited significantly. The results demonstrated that proper concentration of exogenous nitric oxide was able to slow down efficiently the senescence process of detached leaves of S. chinensis after anthesis.

The signal transfer between plants was mediated by compound signals composed of different volatiles. In order to explore the action mode of compound signals, one-year-old poplar(Populus simonii×P. pyramidalis ‘Opera 8277’) cuttings were exposed to four mixed volatiles, I.e. methyl jasmonate(MeJA) + methyl salicylate(MeSA), MeJA + cis-hexenal, MeJA + trans-hexenal, MeJA + benzothiazole, and then the induced activities of three defensive enzymes including peroxidase(POD), polyphenol oxidase(PPO) and phenylalanine ammonia lyase(PAL) were measured. The results showed that all of four mixed volatiles exposure resulted in higher activities of POD, PPO and PAL than only single volatile treatment in intact poplar leaves, indicating that mixed volatiles possessed stronger inducing capability. Moreover the synthetic inducing effect of mixed volatiles was more than the sum of individual volatiles. Among these four mixed volatiles, MeJA + cis-hexenal exhibited the highest inducing capability.

Robinia bella-rosea calli were initiated from the leaves on MS medium supplemented with 5 mg·L^-1 6-BA. The calli were cooled down at 4 ℃ for 2 h in a cryoprotectant （MS+10%DMSO＋0.5 mol·L^-1 Sucrose）, and further refrigerated to -7 ℃ at a rate of 1 ℃·min^-1 by using a programmed temperature-changing freezer. After one hour at -7 ℃ for 1 h, the calli in the cryoprotectant were further refrigerated to -20 ℃ at a rate of 0.1 ℃·min^-1. Being incubated for another hour at -20 ℃, the calli were cooled down to -40 ℃ at a rate of 0.3 ℃·min^-1 and then the calli were transferred and preserved in liquid nitrogen for a day. The low temperature treated calli were thawed at 38 ℃ water bath, and the thawed calli were washed with liquid MS medium with 6-BA 5 mg·L^-1 and 30 g·L^-1 sucrose, then transferred to solid medium and cultured in darkness. Two weeks later, the calli were cultured in light, and showed able to produce fresh and green new callus after 3 d， and the survival rate of the low temperature treated calli reached to 52%. New-produced calli were able to regenerate plantlets.

Provenance variation in growth, stem-form qualities and wood basic density was investigated in a 24-year-old Masson Pine(Pinus massoniana) provenance trial including 49 seed sources located at Chunan county of Zhejiang to select superior provenances for pulp wood and building timber respectively. The results indicated that there existed significant differences in growth rate and wood quality among the provenances. A classical clinal variation pattern responding to the latitude of seed sources was found for DBH, height, individual volume and stem straightness, and water and heat resources of seed sources were the main climatic factors which caused the variation. Productivity of the southern provenances was higher than that of the northern provenances. A weak correlation existed between wood basic density and latitude/longitude, while a strong negative correlation existed between wood basic density and annual mean temperature, temperature in January, frostless season and accumulated temperature over 10 ℃ of the seed source. Genetic correlation analyses suggested that stem straightness could be concurrently improved with selection of fast-growing provenances, whereas the wood basic density was decreased. The range of Masson Pine in China can be divided into Southern, Middle and Northern provenance zone by cluster analysis. Nineteen and six superior provenances were respectively selected for pulpwood and building timber, most of which were from Southern provenance zone with some from Middle provenance zone.

In this study 24 cpSSR primer pairs were screened, and four pairs were found producing DNA fragment length polymorphism from the tested populations of Castanea mollissima. In order to estimate genetic variation and genetic structure of chestnut, we surveyed four wild and nine cultivated populations in China with cpSSR markers. The results showed there were 3 average number of alleles (N_a), 1.635 effective number of alleles (N_e) and 0.381 expected heterozygosity (H_e), from 4 loci in 128 samples. Apparently, the parameters of cpSSR loci were much lower than those revealed by nuclear SSRs. The combinations of all the length variants of alleles from four cpSSR loci finally presented eight haplotypes in the nine populations of C. mollissima. The Qinling mountainous region and Tianmushan mountainous regions possessed the richest haplotype diversity (respectively 0.671 and 0.781). Based on cpSSR data, we estimated the genetic structures of the wild and cultivated chestnut populations and discussed the origins of the cultivated C. mollissima in China.

A cDNA library was constructed with dormant Davidia involucrata seeds by using SMART cDNA Library Construction Kit. The library had a titer of 1.5×10⁶ pfu·mL^-1， with recombinant rate of 98%. The inserted cDNA fragments ranged mainly from 0.5 to 1.0 kb. Total 148 ESTs were obtained from randomly sequencing, and 127 uniESTs were obtained by contiganalsis. By searching on line with BlastN and BlastX, 75 uniESTs were determined to be the tags of genes with putative function and high similarity, 32 uniESTs had low similarity and 13 uniEST had no significant similarity to any protein or DNA sequence in the databases. The present ESTs provide a valuable resource for further research on similarity protein function and molecule mechanism of Davidia involucrata seeds.

Based on four quantitative traits, height, diameter, volume and cellulose content of 240 families of Betula platyphylla, primary core collections were constructed using different sampling proportion(5%，10% and 15%), two distances (Mahalanobis distance and Euclidean distance) calculi, eight hierarchical cluster methods (Single linkage, Complete linkage, Median method, Centroid method, Unweighted pair-group method using arithmetic averages, Weighted pair-group average, flexible method and Ward’s method) and three sampling strategies (random sampling, preferred sampling and deviation sampling). The genetic variation of the quantitative traits among these primary core collections was compared by evaluating the mean difference percentage (MD), variance difference percentage (VD), coincidence rate of range (CR) and changeable rate of coefficient of variation (VR) of the traits. The results showed that the primary core collection was constructed with 10% sampling percent, Mahalanobis distance, preferred sampling strategy, and single linkage clustering method, and it was composed of 24 families of Betula platyphylla and the best representative of total germplasm.

LiDAR (light detection and ranging) is an active remote sensing technique, LiDAR instruments measure the roundtrip time for a pulse of laser energy to travel between the sensor and a target, provide a distance or range from the instrument to the object. In this research individual tree height was measured by combining LiDAR and aerial digital camera imagery. According to the terrain, vegetation and other things of the surface，the LiDAR point clouds were filtered and classified. The Tin Filter algorithm was used for the extraction of ground points and vegetation points. Object-oriented methods were used to identify the single tree in digital camera imagery. Multi-scale and canopy mode were applied in the segmentation, and the nearest neighbors and member function methods were the main classification algorithm, and the edges of canopy polygons were optimized for improving the precision of single tree identification. The classified vegetation points were overlapped with the canopy polygons, and the max height in the polygon was calculated for the correlation with ground measured tree heights. The regression equation was established, and the mean evaluation precision was 74.89％.

With global climate change，extreme weather and climate events such as snow and ice disasters could occur from time to time in the southern China, however techniques for monitoring and evaluating the disasters are missing. In this paper, by using a case study of a continuous and wide range of snow-disaster in the north-eastern part of Guangxi suffered in early 2008, a modified normalized difference snow index (MNDSI) model was constructed based on EOS/MODIS data. Integrated monitoring and classifying methods were then developed in remote sensing monitoring and classification evaluation of the suffered forest area. The techniques would provide a scientific basis for timely response to the disasters, and for disaster prevention and mitigation of such extreme climate events.

The morphological, physiological and biochemical indexes associated with seed germination and seedling growth of Cercidiphyllum japonicum were measured under treatments of seven different polyethylene glycol (PEG) mass concentrations from 95 to 345 g·L^-1. The results showed that the suitable PEG concentration was in a range from 140 to 301 g·L^-1. In this range, the membrane-repair capacity and the drought resistance of seeds were improved, accompanied with the changes of the following indicators. The contents of three osmoregulation substances ［soluble protein, sugar and proline) and the activities of three protective enzymes (superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT)］ were increased, and the content of a final product of lipid peroxidation, malondialdehyde (MDA) was decreased. However, seed germination and seedling growth were inhibited in higher PEG mass concentrations under water stress. With increasing PEG mass concentrations, the contents of soluble sugar, proline and MDA, and the activities of two enzymes (SOD and CAT), were continuously raised, and the enzyme activity of POD was strongly inhibited. In addition, the content of soluble protein was increased first and then decreased in the condition. These results indicated that the seed germination and seedling growth were inhibited under the high PEG mass concentration (≥95 g·L^-1). The results suggest that C. japonicum seed is sensitive to drought stress.

The super cooling point (SCP) and mortality of the pine scale insect (Hemiberlesia pitysophila) that hosted on four different pines of Pinus massoniana, P. elliottii, P. taeda and P. thunbergii were investigated when being exposed to a designated and regulated low temperature. Results showed that a significant effect of pines on SCP of female adults was observed, and the SCPs on P. massoniana and P. thunbergii were 0.9～2.3 ℃ higher than that on the other two pines. The mean SCP of the second instar female nymph on P. massoniana after sex differentiation was 2.08 ℃ higher than that on P. elliottii. However, a separate experiment showed no remarkable difference in the SCPs of the second instar male nymph after sex differentiation between on the two pines. Relations between low temperature and mortality of all insect developing stages and the populations on P. massoniana and P. elliottii all exhibited a revised double-variable Logistic model. Nevertheless, the incipient sensitively low lethal temperature and mortality of these developing stages and the population exposed at -20 ℃ were all lower on P. massoniana than that on P. elliottii. The semi-lethal sum of injurious temperature of the population was lower on P. massoniana than on P. elliottii. The results suggested that the SCP and mortality of Hemiberlesia pitysophila exposed to low temperature were significantly affected by host pines, and its cold tolerance on P. elliottii was lower than that on P. massoniana.

Components of cellulase produced by Leptographium qinlingensis and the optimum conditions for biosyntheses of the enzymes were studied by single factor and orthogonal experiment in this paper. The result showed that Leptographium qinlingensis had a complete cellulase system which was composed of endo-β-1, 4-glucanases (C_X), exo-β-1, 4-glucanases (C₁) and β-1, 4-glucosidase (BG). Furthermore, it was also showed that the enzyme C_X was the major component of the cellulase whose optimum activity (35.215 U) was 13.662 times higher than enzyme C₁ and 8.780 higher times than enzyme BG respectively. A orthogonal experiment indicated that the optimum conditions of enzyme C_X, enzyme C₁ and enzyme BG were different. The optimum conditions to produce enzyme C_X were at 29 ℃ with six-day cultivating time, pH value 4.0 and 150 r·min^-1 rotating speed. Among the four factors (temperature, cultivating time, pH value and rotating speed)， temperature, had the largest impact on producing cellulase by Leptographium qinlingensis，followed by cultivation time and rotating speed.

In this paper, multiple nonlinear regression was used to analyze the relativities of pulping yield and chemical composition, tensile index and tearing index and fiber morphology. The prediction model of pulping properties of fast-growing woods has been established. Chemical composition and pulping properties of three representative fast-growing woods have been studied to verify forecasting models. The result shows that the forecasting value fitting well with the actual value, and the prediction models are feasible.

In the present work, hydrothermal-microwave treatment was used for elm dimension-timber softed treatment. Ratio of longitudinal compressing, single and muti-dimensional minimal curvature radius were used to evaluate the softening result. XRD and FTIR were used for the characterization of surface composition and crystallinity. The results show that hydrothermal-microwave treatment can soften elm dimension-timber significantly, the content of extractive and hemicellulose also decreased significantly. The content of lignin increased slightly（1.73%～0.47%）. In addition, the number of hydroxyl groups on wood surface increased significantly. For the non-crystalline region, microsoft fiber tended to arrange orderly and increase the degree of crystallinity. In the crystal region, the hydroxyl of the sur-microsoft fiber was exposed and the hydrogen bonding enhanced and the width of crystal region increased. When treated under the optimum condition of scheme B, the ratio of longitudinal compressing reached maximum and the single and muti-dimensional radius reached minimum. The main reason of the best softening performance of sample B was the high degree of crytallinity and appropriate number of hydroxyl.

An experimental studied on the influence of larch bark fast pyrolysis in spouting-circulating fluidized bed products yield, in the pyrolysis process of reaction temperature,gas flow,particle size and feed rate,and the effects of the four factors in the interaction of bio-oil yield. The results show that: reaction temperature is the main factor that influences of pyrolysis yield of products, gas flow shows obvious influence, particle size and feed rate have no significant influence; spouting-circulating fluidized bed pyrolysis optimum conditions： reaction temperature 550 ℃,particle size 0.2～0.3 mm,feed rate 20 r·min^-1,gas flow 25 m³·h^-1.

The influence of hot-pressing factors on formaldehyde and other volatile organic compounds （VOCs） were studied in this paper. The particleboard of Larix gmelinii and UF resin were used as main raw materials. Orthogonal design was adopted to analyze the influence of hot-pressing temperature， hot-pressing time， resin content and density on the concentration of formaldehyde and other VOCs. The results showed that the emission of formaldehyde and other VOCs were significantly affected by hot-pressing temperature， time， resin and density. The emission of formaldehyde and other VOCs were obviously decreased in usage with the increasing of hot-pressing temperature， press time and the decreasing of density. Taking formaldehyde and other VOCs emission into account， the optimized condition was hot-pressing temperature of 180℃， hot-pressing time of 37.5 s·mm^-1， resin content of 11%， board density of 0.6 g·cm^-3. The emissions of optimized particleboard satisfied the national standard GB 18580-2001.

The ongoing property rights reform of collectively owned forests has contributed to increasing forest farmers income. Increments of forestry income resulted from acquirement of transfer benefits and an income increase in forest management. Whether farmers transfer benefits are reasonable determines to some extent that the objectives of collective forest property rights system reform can be fully achieved. In this paper we applied forest land and stumpage price theory to examine whether or not the present transfer benefits were reasonable. Following a brief review of the reform and the transfer in Suichuan County， we compared the theoretical prices with the actual prices of forestland and stumpage transfers. It was concluded that， given the present logging quota constraints， farmers transfer income was significantly lower than the theoretical value of the forest. The policy implications of the result were discussed.

Ants are the most abundant and diverse animal species in subterranean ecosystem. They establish various complicated associations with other organisms， in which some ant groups form the oldest mutualism with fungi and become famous mycophagous insects. So far as we know， the ants which rely on fungi as a dominant food source belong to Attini and Solenopsidini， while most attine cultivar fungi are members of genus Leucoagaricus and Leucocoprinus (Basisiomycotina： Agaricales： Lepiotaceae)， with a minority belonging to members of Ascomycotina and Deuteromycotina. The mutualism between ants and fungi has gone through more than 50 million years coevolutionary history； their associations are highly integrated units， characterized by nutritional， physiological， and immune inter dependencies. Meantime， ants and fungi also have other associations， which have become the hot spot of ecological and evolutionary researches. In this paper the utilization of fungi by ants is reviewed in order to provide knowledge and information for studying relationships between ants and fungi in China.

Fine root biomass was measured by soil core sampler in four community type on Tibetan Plateau， of which include two coppice of Betula platyphylla and Quercus aquifolioides， one shrub of Salix oritrepha， and one coniferous woodland of Pinus densata. The fine root density were Betula platyphylla of （785.9±290.4）　g·m^-2， Quercus aquifolioides of （801.0±279.5）　g·m^-2，Salix oritrepha of （376.0±146.0）　g·m^-2 and Pinus densata of （431.2±171.1）　g·m^-2. Result showed that the fine root density of two coppices was significantly higher than that of shrub and coniferous woodland. Dead fine root was 16.2% of the total fine root in Betula platyphylla， and the percentage were about 25% in other three type of forest. Distribution of fine root had the same pattern that high density of fine root appeared at 0～10 cm soil depth.

TWINSPAN classification and DCA ordination were employed here for the quantitative analysis of vegetation under different stands. The vegetation was categorized into 4 types by TWINSPAN classification method. The vegetation was categorized into 4 ecological types by DCA ordination. The foremost environmental factor in the DCA ordination of the vegetation was soil salinity. The result of DCA ordination was consistent with that of TWINSPAN classification， which was further derived from refinement of the result of the DCA.

To provide the scientific basis for establishing the efficient cultivation and management measures of Torreya grandis cv. ‘Merrillii', the process of the female flower bud differentiation was studied with the paraffin method. Results indicated that the ovulating strobilus differentiation of T. grandis cv. `Merrillii' was mainly in the winter and the early spring. The ovulate strobilus formed in the middle and upper part of young tips of the mixed-bud. Their primordia appeared in early November before which there was no distinction in the dissected shape between the mixed-bud and the nutrition bud. Through the developments of bract, ovule scale, nucellus and integument, the strobilus started to blossom in the next mid-April and entered in a period of free nucleus of endosperm without formed female gametophyte and archegonium. The whole process lasted about 160 d. The illumination and themoisture in summer and autumn were main conditions to affect the female flower bud differentiation.

The key metabolism factors for bloom of Phyllostachys heteroclada olive and Neosinocalamus affinis Keng were analyzed by using the principal component analysis method. The results showed that GA₃, GA₃/ABA and starch were the most important factors related to bloom of the two bamboo species, followed by soluble sugar, activities of starch enzyme and glutaminase. GA₃, starch and soluble sugar with a certain content, and GA/ABA were positively correlated to the bamboo blossom. However, ZT, ZT/ABA and starch enzyme activity had a clear link to bamboo flowering reversion of Phyllostachys heteroclada. In order to know bamboo flowering more clearly, a preliminary simulating model of bamboo flowering was constructed. The model shows that the bamboo flowering procedure is lengthy and complicated. Any influence and break in the procedure would probably accelerate or terminate growth and florescence course, which could be the reason why bamboo florescence is so variable.

The dead surface combustibles of artificial coniferous forests in Chengde were focused in this paper. Predicting models between fuel loading and the stand and landform factors, as well as between water ratio of combustibles and weather factors were established with a regression analysis method. The models were effective in calculating fuel loading and water ratio. Fuel loading, water ratio and thickness of combustibles are regarded as the parameters of potential surface fire behavior. Based on a cluster analysis, the potential surface fire behavior of different forest lands was divided into 3 classes: strong, medium, or weak surface fire. The results indicated that most of artificial coniferous forests were in the status of medium surface fire, the risk of surface fire of mixed forests was lower than pure forests, and that of sapling forests and half-mature forests was higher than near-mature forests.

A preliminary investigation on the characteristics of animals in the soil of Huangshan forests was conducted. Invertebrates included 33 genera in 11 classes and 5 phyla, among which Acarina, Collembola and Nematoda were dominant groups, occupied 88.21% of the total samples, and formed the main body of the forest soil animal community. The others included common groups and rare groups, respectively accounting for 5.85% and 5.98%. It is warm and humid in the mid-subtropical region of China, covered with lush vegetation has and with an abundant resource of animals in the soil underneath. Soil animal abundance was affected by a number of factors, among which vegetation and soil types are the main limiting factors. Based on data collected from 4 sample sites the evergreen broad-leaved forest and the conifer-broad leaved mixed forest had the highest average density of soil animals, rearching up to 68.80 and 66.53 10⁴·m^-3, respectively, while the artificial coniferous forest had the lowest density, with only 36.43 10⁴·m^-3.The vertical distribution of animals in the soil was closely related with the surface accumulation of organic matter and the vertical variation of soil physiochemical characteistics. The results showed the soil animals were mainly distributed in litter and humus layers, and obviously accumulated on of the soil surface and sharply decreased downward.

This variety was optimally selected from Ginkgo biloba which was introduced from An'lu, Hubei province through many years of observation. The variety has a long petiole and fan-shaped leaves with shallow perforation end and wavy leave margin. The leaf color is golden yellow in spring and in summer though a few of leaves turn into yellowish green in summer. The female cone possesses a long stem, with 1～2 discoid ovule plat(s) at its end, and the ovules attached to the plat develop into seeds. The variety has a high ornamental value due to its golden yellow leaves in spring, summer and autumn, with easy propagation and simple management. It can be used in sides of streets, gardens, courtyards, parks, touring spots and etc., with high promoted and applied value.