Three-year study was carried out to determine amount, component, seasonal dynamics and chemistry of litterfall and its returns of nutrient and energy in plantations of Fokienia hodginsii and Cunninghamia lanceolata in Fujian Province.Mean annual litterfall were up to 731.83 g·m ^-2 in F. hodginsii stand, being 1.34 times higher than that in C. lanceolata stand, of which 65.29% was occupied by needle litter. Except for components of needle and flower, the proportions of other fractions to total litterfall of F. hodginsii were all lower than those of C. lanceolata. Monthly litterfall of both stands peaked in April (or May) and November (or December), with the highest in December for F. hodginsii stand. While for C. lanceolata stand, peak values were close and there occurred another peak of litterfall in August. Annual returns of nutrient and energy of litterfall in F. hodginsii stand was 13.961 g·m ^-2 and 14 636.58 kJ·m ^-2 respectively, being respective 1.16 and 1.19 times as much as those in the stand of C. lanceolata. Moreover, nutrient and energy returns through needle litter was the primary pathway, with greater values also found in the stand of F. hodginsii.Litter chemistry (e.g. content of lignin and nitrogen) can exert a profound influence on the decay rate. In this study, contents of N, P and readily decomposable materials (such as water-soluble compounds, hemicellulose and coarse protein) in needle litter of F. hodginsii were higher than those of C. lanceolata. While the reverse was true for contents of decay-resistant materials and ratios of C/N, C/P, lignin/N and lignin/P in needle litter. These indicated that quality of needle litter of F. hodginsii was better than that of C. lanceolata, thus faster rates of decomposition and nutrient release occurred in litter of F. hodginsii in contrast to those of C. lanceolata.

Total nitrogen (N) and organic carbon ? in soil, forest floor and litterfall, and N mineralization rates were compared between pure and mixed Pinus luchuensis plantations on similar soils in the northern Okinawa Island, Japan. Mean accumulations of N and organic C on the forest floor were 133 kg·hm^-22 and 7 199 kg·hm^-2 for the pure pine stand, 105 kg·hm^-2 and 6 143 kg·hm^-2 for the mixed stands. However, in the surface 10 cm mineral soil, the mixed stands had an average of 493 kg·hm^-2 and 5 554 kg·hm^-2 more than the pure pine stand (p<0.001). Amount of N mineralized from soil during 30-day incubation was 18 % greater in the mixed stands than in the pure stand (p<0.01). Average seasonal soil mineralizable N (NH₄⁺+NO₃^-) concentration was 22% greater in the mixed stands than in the pure pine stand (p<0.01). The mixed stands returned an average of 43.7 kg·hm^-2a^-1 (about 70%) and 1 655 kg·hm^-22a^-2 (about 39%) in litterfall more than the pure stand did. The greater litterfall N input in the mixed stands was due to higher concentration in the pine needle litter and the presence of high-N broadleaf litter as well. The results from this study suggest that conifers have different N cycling when mixed with broad-leaved trees from when in pure stand.

A study on precipitation in the Abies smithii forest ecosystem of Mountain Sejila in Tibet has been done in the year of 2000—2001. Contents of the nutrient elements and ions of precipitation have been analysed. The results showed: the content and input of nutrients from precipitation in the Abies smithii forest ecosystem of Mountain Sejila in Tibet were Zn >N >Mg >Fe >Ca >P >Na >K. The input quantities were 25.1、23.3、8.1、4.1、1.9、0.4、0.026、0.007 kg·hm^-2a^-1 respectively, and the input quantities of SO₄^2-、HCO₃^-and Cl^- were 742.6、74.3 and 51.6 kg·hm^-2a^-1 respectively. The main nutrient inputs were from rainfall. The main element in eluviations from forest canopy was the element Na, but that from tree trunks was the element P. The forest canopy possessed absorption capabilities upon the elements and/or ions of Fe, Zn, HCO₃^-, Cl^-, N, SO^42-and so on.

The Bao-Lan railway crosses the Shapotou section, 50 kilometres long, of the Tengger sand desert, where there is an annual mean precipitation 186 mm and mobile sand dunes which have relative height of more than 20 m goahead 4 meters toward the south-east. Combined engineering ways and biological measures without irrigation the system controlling sand began to establish after 1956. The protective system has insured the Bao-Lan railway smoothly straightway for near a half century, and has made 10¹⁰ Yuan accumulative economic benefit. Although precursors successfully selected anti-drought local species and effective engineering systems to stabilize shifting sand, it was not easy to forecast that succession of soil-plant system would endanger sustainable stability of the protective system. In the process of artificial plants toward natural vegetation the plant coverage underwent a self-sparse course from increase to decrease and from shrubs to semi-shrubs to herbaceous, which debased the function of reducing wind speed and controlling strong wind. Soil developed from aeolian sand soil to Calcic-Orthic Aridisols. Development of bio-crust on the surface increased ability of anti-erosion by wind. Succession of soil-plant system had made redistribution of precipitation in eco-system change fully; meanwhile because of imperfect of collocation of prevention shrubs, a drought soil layer gradually developed in the between 50 cm and 500 cm depth with cause of formation of plant transpiration. A new pattern of water balance obviously imperils sustainable use of water resource and the stability of the protective system.

The transmissivity of the broad-leaved Korean Pine forest was calculated according to the fixed-point automatic measurements of global radiation above the forest and the transmission on the floor, from May 22 to October 14. The results showed that the transmissivity was correlated to sky conditions. The diurnal variation curve of the transmissivity was flatter under overcast and fluctuant under scattered sky. The violent fluctuation of the curves appeared in clear sky. These phenomena were due to the gaps of the crown and the percentage of direct ray in the global radiation. However, the comparison of fixed-point and wandering measurements showed that the difference of daily averaged transmissivities between the two methods was little. So the daily averaged transmissivities were reasonable to represent the characteristics of the crown. The transmissivity also varied with the growing stage not only in the values, but also the appearing times of the peak of the diurnal curves. Seasonal variation curve of the transmissivity (daily averaged) was took U shape during the measured period. The transmissivity was higher in late May and early October, lower and stable in July and August. The relationship between the transmissivity and days' number fitted quartic polynomial. This reflected the seasonal variation of leaf area index of the forest.

Based on the summarization of the former aeronion assessment models, the article put forward the concept of aeroanion coefficient, established the assessment models of aeroanion coefficient(p) and forest aeroion(FCI). Besides, after analyzing the data of aeroanion concentration observed in 10 forestry recreational areas through the method of standard normal logarithm transformation, the article set up the standard grades of forest aeroion(SGFA) and evaluating index standard grades of forest aeroion(EISGFA). The values of SGFA(with the unit of entries·cm^-3), p and EISGFA were divided into six grades, respectively, >3 000,2 000～3 000,1 500～2 000,1 000～1 500, 400～1 000, <400; >0.8,0.7～0.8,0.6～0.7,0.5～0.6,0.4～0.5,<0.4 and >2.4,1.4～2.4,0.9～1.4,0.5～0.9,0.16～0.5,<0.16 respectively。According to the biological effect of aeroanion to the body of human being, this article divided the value spectrum of SGFA into three sections, respectively, critical section (<400), allowable section (400～1 000) and hygienical section (>1 000). With the using of the standards and the indexes, the aeroanion status of the main sightseeing areas of Zhangjiajie Forestry Park was successfully evaluated.

The Pinus elliottii seedlings were cultured in nursery land in Fenyi County,Jiangxi Province(27°30′N,114°30′E).The seedlings were treated with 4 different methods, named treatment 1(steady-state nutrition+Pt), treatment 2 (nonfertilization + Pt), treatment 3(steady-state nutrition+soil from pine forest),treatment 4 (normal fertilization+soil from pine forest) respectively. For the seedlings of steady-state nutrition, the relative nutrient addition rate was 7.5%, the amount of nutrient added during the cultural period was calculated according to the theory of steady-state mineral nutrition.The amount of N element for per seedling in steady-state nutrition treatment was 39.22 mg ,and was 55.20 mg for per seedling in normal fertilization without PK and any micronutrients treatment.At the end of growing season, the growth and the percentage of ectomycorrhizal infection of seedlings in different treatments were determined. The result showed that the ability to form ectomycorrhiza of Pinus elliottii seedlings was stronger, inoculated with both Pt and natural ectomycorrhiza. However, the highest percentage of ectomycorrhizal infection was in treatment 1(steady-state nutrition + Pt), which amounted to 94.8%. The growth of seedlings indicated that treatment 1 > treatment 3 > treatment 2 > treatment 4. For example,compared with the seedlings in treatment 2(nonfertilization+Pt),the height and the basal diameter of seedlings in treatment 1 were 20.5% and 14.0% higher,the number and the total length of the lateral roots 25.6%,40.9% higher,the fresh weights of leaf, stem, root,and the whole plant 34.6%, 43.7%, 38.8% ,and 37.0% higher,and the dry weights of those parts above mentioned 25.7%, 38.6%, 42.4% ,and 32.7% higher, respectively. There was a larger difference between treatment 1 and treatment 4.The results demonstrated the comprehensive effect of steady-state mineral nutrition and Pt. And the effect of Pt on growth of seedlings would be realized better by scientific fertilization. The growth of seedlings in treatment 4 was worst. Finally, the results of this study were discussed from the aspects of the interaction mechanism between the steady-state mineral nutrition and Pt mycorrhization,as well its practical application.

Two tropical seedlings, Calophyllum polyanthum, the canopy species, and Barringtonia macrostachya, the middle layer species, growing in man-made shade conditions (8%, 25% of full sunlight) were investigated through the whole fog season between October 2000 and December 2001 by monitoring the photosynthetic characteristics, antioxidant enzyme activities of SOD, CAT and APX, and MDA content as temperature fell in Xishuangbanna, SW China. Leaves were sampled at approximately 30 days interval. The net photosynthetic rate and chlorophyll content of two species declined markedly in late December compared with those in October. The photochemical efficiency in dawn was not different statistically in fog season except for C. polyanthum growing in moderate light conditions, indicating that PSII was not damaged by photoinhibition under chilling due to the protective responses of the photosynthetic system to the stress. SOD and APX activities in leaves of both species increased from October to early December, and MDA content did not change greatly during this period. While in late December, SOD and APX activities in leaves of plants growing in moderate light declined, and MDA content increased. But CAT activity fluctuated through the whole fog season. APX was important scavengers for this study. A strong positive correlation occurred between APX acitivities and lowest ambient temperatures, suggesting that this enzyme was temperature-regulated, and the decline of CAT activity did not mean the decline of scavenging oxygen enzymes. According to the data of net photosynthetic parameters, enzymatic activities and MDA content, we concluded that the canopy species, C. polyanthum, was affected more significantly by low temperature than the middle layer species, B. macrostachya, and the seedlings growing in moderate light were affected more significantly by low temperature than those growing in low light.The results provided evidence for the ability of the tropical rainforest seedlings to activate enzymatic defense mechanisms to limit the production of free radicals to protect membrane integrity under chilling stress. The protective role of the decline of the chlorophyll was also discussed.

In order to improve quality of somatic embryos and rooting frequency in Larix principis-rupprechtii,2,4-dichlorophenoxy acetic acid(2,4-D) was replaced by naphthalene acetic acid(NAA),which improved the quality of early stage embryos, and thus improved the formation of high quality somatic embryos. Subcultures on this maturation medium, containing 3% maltose to replace sucrose, together with 4% PEG4000 and 0.1% activated charcoal (AC), the maturation frequency of somatic embryos was not lower (106.7 embryos per gram embryogenic calli, EC), but the quality of somatic embryos was improved distinctly, such as the hypocotyl was longer and the rooting frequency was up to 57.89%. The root system formed grew normal. Woody plant medium (WPM) as germination medium for somatic embryos, containing phloroglucinol (PG) 6 mg·L^-1 was the best concerning embryo germination and rooting.

Platanus acerifolia is a famous shade tree, which plays a very important role in city afforestation. In this paper the P. acerifolia leaf regeneration system was thoroughly discussed for the first time. The leaves of P. acerifolia were used as the experimental material. Several factors such as hormone concentration, explant condition, illumination condition, and so on were investigated to optimize the regeneration system in vitro. The experimental results showed that leaf situation can greatly affect P. acerifolia regeneration frequency. The best explants were those 40 days apical leaves from the cultured plantlets. The high frequency of shoot regeneration was observed when leaf explants were cultured on MS medium supplemented with 1.5 mg·L^-1 6-BA, 0.5 mg·L^-1 IBA and 0.5 mg·L ^-1 KT. First, the leaves were cultured in dark. After 7 days the explants were transferred under light and began to directly regenerate adventitious buds in about 15 days. The maximum number of the adventitious buds was observed within 20 to 30 days. The shoot differentiation frequency was more than 98%. When the shoots grew to 1～2 cm high, they were cut from leaves, then transferred on to shoot elongation medium (MS+0.3 mg·L ^-1 6-BA+0.05 mg·L^-1 NAA+30 mg·L^-1 Ad)until plantlets coming into being. Finally, the plantlets were rooted on the root differentiation medium (1/2MS+0.1 mg·L ^-1NAA) and developed into whole plants within 14 days. This regeneration system can be applied to P.acerifolia transgenic manipulation.

Thirty-two Pinus massoniana clones for pulp use were selected from forests of fine provenance, mixed families and progeny test of seed orchard by two steps of selection, based on the growth, wood property of the ortets and cutting rooting abilities. The average height and DBH growth of three years old of these clones were 28.6 percent and 16.7 percent respectively higher than those from seedlings, and average gain of wood density got to 8.7 percent. And rooting rate of all these clones was over 80 percent, increased 28 percent than all the clones selected by first step. 0.33 hm² cutting orchard on the hillside was constructed to intensively produce cuttings according to the tests on construction ways, pruning and fertilization. 50 000 degree Ⅰ, 37 500 degree Ⅱ and 62 500 degree Ⅲ cuttings could be collected per hectare of this cutting orchard each time, and could be cut for 3 times in a year. With all above techniques, 48 hm2 clonal forests for pulp use of those clones had been planted in five places in Fujian Province. And container stecklings did good to increase the planting survival rate.

The high genetic quality and ample yield are the key to seed orchard management, and also an urgent problem awaiting solution at present. This task is closly related with the investigation on the mating pattern of seed orchards. Therefore, during 1984—2000 in a seed orchard of Pinus tabulaeformis, located in Xingcheng County, Liaoning Province, open-pollination seeds were collected from the seed orchard in 5 years (1984, 1987, 1993, 1996 and 2000), Seeds were germinated, and both diploid embryos and haploid gametophytes were analyzed by starch-gel electrophoresis, while 10 loci were involved for both kinds of tissue and used as genetic markers for estimating mating index and contamination rates. Firstly, the variations of mating system with time and factors influencing gametogamy were revealed, the multilocus outcrossing rates before thinning(1984 and 1993) were 0.975 and 0.962 respectively, the multilocus outcrossing rates after turnning decreased to 0.795 and 0.801 respectively for 1996 and 2000, while the multilocus selfing rates increased to 0.205 and 0.199. Secondly, by studing the variation of enzyme bands of seed samples in different positions of crown, the spatial variations of mating system was proclaimed too, the outcrossing rate was higher for seeds from the upper position of the crown in comparison with those from the middle and lower position. At last, pollen contamination rates of the seed orchard for 4 years were analyzed. The estimation method relies on differences of electrophoretic allele frequencies at single loci between natural stands and the seed orchard, from which an average contamination at loci was estimated. Results showed that the pollen contamination rates of the seed orchard for 4 years ranged from 0.354 to 0.583. Factors influencing the pollen contamination of seed orchard have been discussed and some related management measures proposed.

The paper dealt with the niche characteristics of 4 main tree populations in man_natural mixed forest of C.lanceolata and broadleaf trees. The niche breadth, niche proportional similarity and niche overlap of main tree populations were determined, and the ecological significance of results were analyzed. Meanwhile the main populations in man_natural mixed forest were studed by the Lotka_Volterra equation of competition. The results showed that the relative dominance of Cunninghamia lanceolata and Castanopsis carlesii was respectively 87.45% and 12.55% when the stand reaches balance, I.e.those two species can jointly dominate a community and the whole community would be controlled by Cunninghamia lanceolata population.

Based on the survey for 6 sample artificial Robinia pseudoacacia forestland sites and the analysis of soil water content and bole growth ring, the relationship of growing status(about height, DBH and volume and soil water deficit was studied. The results showed that the deficit degree of soil water was related to the growth status of Robinia pseudoacacia. In Yijun County, southern Shannxi, there is no severe soil water deficit, no obvious soil desiccation, the Robinia pseudoacacia growth was good. In Fu County, dried soil layer has been formed because of soil desiccation that already has had bad effects on the growth of Robinia pseudoacacia. In Wuqi, Ansai, Suide and Mizhi County, soil water deficit become severer, dried soil layer was worse, which caused artificial Robinia pseudoacacia plantation to form into low efficient and productive one and limited the ecological functions of artificial Robinia pseudoacacia plantation suggesting that those areas were not suitable for the growth of artificial Robinia pseudoacacia plantation.

The effects of planting density on growth and economic benefit of Masson Pine plantation were analyzed by using the data obtained year by year during 11 years from the experiment stand (including treatments of A,B,C,D, their planting density is 1 667, 3 333, 5 000, 6 667 trees5hm -2 respectively), the results showed that it had significant effects on stand growth, stand structure and mill run. With the increase of planting density, diameter at breast height(DBH), single tree volume, crown diameter, ratio of crown length to tree height decreased, but growing stock, tree height/DBH, self_thinning intensity increased, stand total mill run, trees percentage of small logs and mill run of small timber increased, and first thinning time was earlier. The planting density had no significant effect on tree height. Mill run of C and D was more 34.0%, 43.0% than that of A respectively. By a synthetic analysis of mill run, the cost of production and output value, planting density of cultivating short rotation industry timber could be determined as 3 333～5 000 trees5hm^-2-2,/SUP.

The volatile organic compounds emitted from 3-year-old ash-leaf maple seedlings (Acer negundo) under drought stress were identified. Emissions of nine volatile compounds, including butyl alcohol, pentyl alcohol, trans-2-hexen-1-al, cis-3-hexen-1-ol, pentanal, pentanoic acid, hexanal, hexanoic acid, and acetophenone, increased and a tenth compound, longifolene, decreased when the trees were subjected to water stress. After the trees were re-watered the amount of acetophenone increased, but the amounts of other volatiles including longifolene decreased. The response of Asian longhorned beetle (ALB, Anoplophora glabripennis M.) to volatiles was examined with GC-EAD, and with field bioassay using traps and synthetic compounds. Butyl alcohol, pentyl alcohol and cis-3-hexen-1-ol, elicited antennal responses from ALB. The activity was confirmed in the field test. Thus, drought stress appears to play an important role in the host selection behavior of ALB.

12 stand description factors affecting the harm extent of the Gypsy moth(Ocneria dispar) was studied,through stepwise regression analysis from which three significant ones were selected:crown density, infertile extent of soil and forest area.The results showed that a direct correlation exists between infertile extent of soil and the harm extent of the gypsy moth,a significant inverse correlation exists between the other two key factors and the harm extent of this insect.Using the three key factors a multiphase linear regression model was made for risk analysis of the harm extent of the gypsy moth.

The soft scale, Eulecanium gigantea (Shinji) (Homoptera: Coccoidea; Coccidae) was an important pest in cities of northern China in recent years. During 1998—1999, five experimental districts with different degrees of air pollution in Taiyuan City and one clean area as the contrast district at campus of Shanxi Agricultural University located in Taigu County were selected. The nutriological relationship between the soft scale population increase and its host plant was studied. The results showed that (1) In the pollution districts, the quantity of reductive sugar, general sugar, soluble protein and amino acids in twigs and leaves of the host tree, Sophora japonica, were much more than those in the clean district. (2) In the sample districts, the soft scale population densities increased as the air pollution deteriorated. At the same time, the contents of reductive sugar and soluble protein in twigs were positively correlated to the population density of the scale insect significantly. The regression equations were made out respectively in Y₁=87.602 8X₁-117.825 0, with correlation coefficient r₁=0.98, and Y₂=2.893 6X₂-142.152 3, with r₂=0.84. (3) During March to October, two peaks and one valley were appeared in the content fluctuation of the nutrition substances in host tree twigs. That echoed respectively to the two feeding stages and one egg stage of the soft scale in its life cycle. It was concluded that a higher content of nutrition substances in the host tree in polluted urban environment may be one of the important factors which make the scale insect greatly propagating. An nutriological evidence was provided by this research in the trend of scale insect population to increase in polluted urban environment.

The Phytoseiidae Mite, Typhlodromus bambusae, was a dominant predator associated with the mite pests of Moso Bamboo. The effects of 6 constant temperatures (16,20,24,28,32 and 36℃) on development, oviposition and survival of T. bambusae, reared on Schizotetranychus bambusae, were studied. The eggs could not hatch at 36℃. Within the range of 16～32℃, the development time of egg, larva, protonymph, deutonymph shortened as temperature increased. The developmental threshold temperatures for egg, lava, protonymph, deutonymph, from egg to adult, and pre-oviposition were 10.21, 10.67, 10.94, 10.76, 10.44 and 13.36℃, respectively. The developmental effective accumulated temperatures for egg, lava, protonymph, deutonymph, from egg to adult, and female adult pre-oviposition were 36.18,12.61,21.46,21.63,93.71 and 39.43 DD, respectively. The nonlinear Wang-Nan-Ding model gave a good fit to the relationship between developmental rate and temperature. Percentage of survival was the highest (92.50%) at 20℃, and lowest (67.50%) at 32℃. Temperature affected fecundity and longevity significantly. The oviposition period was the longest (24.43d) at 20℃, whereas the shortest (5.14d) at 32℃. The eggs laid by per female ranged from 31.26 at 24℃ to 9.20 at 32℃. A nonlinear regression model could fit the relationship between eggs laid by per female (Y) and temperature (T). The equation was Y=-171.694 2+17.273 2T-0.036 3T²(R=0.964 8_*).

In order to provide more timber for pulp-making, 14 fast growing poplar varieties were widely cultivated in Shandong Province and were studied with respects to their volume growth, fiber shape, chemical composition and economic indices and systemic techniques. The results showed that: (1) The average fiber length and fiber content of 14 poplar varieties in 6-year-old stand is 0.863～1.051mm and 51.37%～58.17% respectively. All the varieties conformed to the pulp-making standard. Taking both the growth and fiber characteristics into consideration, poplar varieties of Populus×euramericana‘Zhong Lin 46', P. × eur. ‘Zhong Lin 23', P. deltoides cv.`LUX' and P. × eur. ‘Zhong Lin 28' were the best choice to afforest the pulp-making stands and. P. × eur. ‘San Martino', P. × eur. ‘Zhong Lin 14', P. × eur. ‘Zhong Lin 45', P. × eur. ‘Luisa Avanzo' and P. × eur. ‘Cima' were also suitable for it. (2)The technical maturity of stands for pulp-making was basically 6～8 years old with the optimal age of 8 years. In order to get high yield and obtain the optimal fiber that were suitable for pulp-making, the optimal stand density is 840～1 665 tree·hm^-2. With the intensive cultived techniques, the optimal rotation age for poplar stands with the density of 1 665, 1 110 and 840 tree·hm^-2 were 6, 6～7 and 7～8 years respectively. (3) Intercropping, fertilization and tending etc. were necessary for high wood yield and high level benefit. Adoption of comprehensive measures and pulp-oriented cultivated techniques could short the oriented age and result in high yield. The annual volume growth of poplar varieties could be as high as 27～31.5、m3·hm^-2. The net benefit, CBR, investment effect coefficient, IRR, NPV and PVI were 3 687.0 yuan·hm^-2, 0.22, 25.5%, 9 472.5 yuan·hm^-2 and 1.80 respectively, which showed a positive investment.

Two tree species wood planted in China, Poplar and Chinese Fir, were chosen as the research materials. The wood surface properties, e.g. the surface free energy, the surface polarity, the surface chemical function groups and the influence of temperature on the wood surface properties, as well as the relationship between the wood surface properties and surface chemical function group were studied. The results revealed that Chinese Fir had higher surface free energy (42.35 mN·m^-1) and dispersive surface free energy (41.61 mN·m^-1) than that of Poplar (38.93 mN·m^-1and 35.52 mN·m^-1each), but the polarity surface free energy of Poplar (3.41mN·m^-1) was higher than that of Chinese Fir (0.74 mN·m^-1). The total surface free energy and dispersive surface free energy of Poplar and Chinese Fir decreased with the temperature increasing of treatment resulted from the comprehensive effect of the change of hydroxide and the de-hydroxide of the wood surface. The three function groups of wood surface were hydroxide, alkyl and aldehyde. The ratio of hydroxide to alkyl and hydroxide to aldehyde decreased the wood was treated in high temperature, which imdicated that the process of de-hydroxide was a process of hydroxide density decreasing on wood surface. There was an obvious correlativity between surface free energy of wood and the change of chemical functional group on wood surface.

The wood samples of 9 triploid clones of Populus tomentosa were cut from 9-year-old clonal stand.The oven-dried and air-dried samples were used to study their genetic variation in shrinkage. The results indicated that there were significant differences between clones and all the coefficients of shrinkage that were found to be under strong genetic control. The vertical variation pattern within tree of shrinkage was downward with the tree height. The clonal repeatability's in shrinkage of oven-dried and air-dried timber in volume, radial and tangential direction were respectively 0.89,0.95,0.84,0.67,0.84 and 0.68.

With differential thermal balance, and by taking a comparative study of DTA/TG curves of Phosphoric acid and Zinc chloride, as well as the curves during pyrolysis of wood dust, separated cellulose and separated lignin which have H₃PO₄ and ZnCl 2 added respectively, It found that: H₃PO₄ and ZnCl₂ demonstrate similar DTA/TG curves, also both of these two testing agents function stable. However, at high temperature of evaporation, H₃PO₄'s initial evaporation temperature, final temperature of pyrolysis and the remains are all obviously higher than that of ZnCl₂. For wood dust with the two testing agents, their DTA/TG curves during pyrolysis show similar. At the beginning, they catalyze carbonization and almost finish carbonization at around 200℃. As the temperature goes higher and higher, they enter into main activation duration. At high temperature duration, both of them have evaporation reaction. Besides, there exist differences between them. The suitable activation duration of H₃PO₄-dust is obviously wider than that of ZnCl₂-dust. Meanwhile, the initial evaporation temperature, final temperature of pyrolysis and the remains of the former are higher. All of these approve that the function of H₃PO₄ protection for carbon is stronger than ZnCl₂. For the influences to cellulose pyrolysis, the two testing agents function as the same as to wood dust. Meanwhile, we got that the effects to the cellulose pyrolysis are less different, while those to lignin pyrolysis are more different. H₃PO₄ affect the whole duration of lignin pyrolysis. However, the effect is less than that to cellulose or wood dust. At the beginning of lignin pyrolysis, ZnCl₂ catalyze carbonization reaction, while in medium and later duration little effect is achieved. From the DTA/TG curves and combined with minor carbonization experiment, we got that under this experiment, the best temperature by H₃PO₄ method is about 400℃, and by ZnCl₂ method is about 500℃.

The heat and mass transfer and coupling effect in wood drying were studied by applying the thermodynamics of irreversible processes. The relation of the heat and mass transfer and contained coupling effect were deduced in terms of the rates of entropy producing in irreversible processes. It might be sought that the moisture gradient not only leads to a water mass flux, but also gives rise to a heat flux. It is interesting to note that the force to drive water mass flux is the diffusivity gradient.

Applications of BP network and fractional dimension were introduced. Fractional characters such as fractional dimensions of gray scale image surface and tree crown contour ,and 4 directional fractional dimensions in different directions, and shape characters of tree crown such as the height of tree crown and 8 crown breadths in 8 equal division place were employed to recognize the tree crown. And a tree crown recognition system was established in which there are 15 nodes of tree crown features and image fractional dimensions in the input layer, 6 nodes of tree crown types in the output layer and 1 node in the implicit layer. The experiment showed that the system could recognize the tree crown precisely.

The mixed proportion was decided based on principle of Lotka-Volterra interspecific competition.The results showed that:the mixed proportion between Chinese Fir and its mixed tree species changed in terms of different tree species and the proportion between purpose tree species and one same mixed tree species changed according to different groups of site type,and the variation coefficients of the mixed proportion changed with the tree species used for mix.Morever comparing with traditional methods this new method was more scientific than other old ones.

The numbers of firefighters dispatched in initial attacks of forest fires with different fire parameters in Heilongjiang Province were obtained by sending questionnaires to county level fire commanders.Nonlinear Multivariable models were established to simulate the number from fire parameters in the paper.Analysis was also made on the factors affecting the dispatch decision.The results showed that (1)the models could simulate the process very well.(2)The models constructed based on the data from a single county had much better performance than those based on combined data of several counties.(3)Most of the commanders involved regarded wind as the principal factor in the decision-making and the distance to burning site of the second importance and the area burned the third when the area is less then 2 hm².(4)The weight of distance to burning site increased with the years of fire fighting that a fire commander has engaged.

The changes of photochemical quenching(q_P) and non-photochemical quenching(q_N)of chlorophyll a fluorescence in leaves of four tree seedlings (Gleditsia sinensis,Juglans regia, Diospyros kaki and Diospyros lotus) were different between two different water stress ways:detached drought treatment and potted drought treatment. After 4 hours dehydration by leaf detaching,the q_P values had significant decrease except J. Regia, only 6 hours later, the q_P values compared with contrast decreased significantly in four tree seedlings(P>0.05), but the range of reduction(G. sinensis, J. regia and D. lotus) was just 2.5% to 6.4%. D. kaki,however,got to 31.3%. While the q_N values increased significantly with conducting dehydration of the detached leaves. However, the q_P values of four species showed no significant decrease when they were growing in pots under soil water stress(40%～60%RWC) for 30 days; and the q_N values decreased obviously with a exception in J. regia, which was consistent with that of detached leaf treatment. The results suggested that some difference or changes in mechanism of excess light energy dissipation might perform in four seedlings by short-term and long-term water stress.

In order to preserve Wuyi Mountain effectively and analyze the relationship between human activity and landscape structure,the Wuyishan Scenery District,which was disturbed stronger than the other 3 parts of Wuyi Mountain,was chosen for the study,and its spatial pattern was studied by landscape indices at two scale levels of landscape element and the whole landscape.The results showed as follows:①Pinus massoniana forest was the matrix landscape in Wuyishan Scenery District,its dominance was very obvious(60.01% of area).Farmland(12.89%) and Camellia sinensis plantation(11.68%) was the second and the third respectively;②From the results of mean patch shape index(MSI_i),mean proximate circular index(MPCI_i) and mean patch stretch index(MPSI_i),showed that Pinus massoniana forest,farmland and Camellia sinensis plantation were three most complicated in patch shape,while residential area was the simplest;③The calculation results of mean patch area(MPA_i),patch density(PD_i) and fragmentation index(FN_i)indicated that the degree of fragmentation of residential area was highest,that of Camellia sinensis plantation and economic forest ranked the second and the third respectively,while that of Pinus massoniana forest was lowest.In addition,the separation index(SI_i)also revealed that the separation degree of residential area was highest,while that of Pinus massoniana forest was lowest.These results proved powerfully that human activity was one of the main factors breaking the landscape into fragments;④At the whole landscape level,the values of biodiversity(H),dominance(D),evenness (H′) and degree of fragmentation(FN) of the Wuyishan Scenery District were 0.573 1,0.426 9,0.405 7 and 0.005 6 respectively.After comparisons between the Wuyishan Scenery District and other areas(including forest landscape,agriculture landscape,urban landscape,wetland landscape and desert oases landscape)were further analyzed,it was concuded that the Wuyishan Scenery District is one of the areas which have been well preserved up to now.

Based on the measurement of all individuals of population at different successional stage and following excavation of clones, the density and biomass dynamics of Hippophae rhamnoides L.subsp.sinensis population in Mu Us sandland were analyzed with the methods of plots arranged with age and reverse age class addition(RAA). The main results were as follows:(1)The density of clone population increased with the population growth before 5-year-old. The population biomass accumulating also increased by Logistic equation in the period of age structure of population developed from increasing type to mid-decreasing type. Then they tended to be decrease. While the population density, population biomass augmented again with the emergence of gap regeneration, and the dominant status of H. rhamnoides L.subsp.sinensis population and the stability of the community were maintained.(2)The decrease process of density of daughter ramets population lagged behind that of mother ramets population, and the numerical ratio of daughter ramets population within the population gradually enlarged. As the population thinned, the composition of population changed from more clones with less daughter ramets to less clones with more daughter ramets and the genetic diversity of population reduced.(3)The prosperous stage of biomass accumulation appeared from 8-year-old to 16-year-old and its peak appeared at 12-year-old. And the relationship between the individual mean weight and population density could be expressed by the law of power-3/2 in the period of age structure of population developed from stable type to decreasing type.

dsRNA in Cryphonectria parasitica could be transmitted to progeny through conidia with varying efficiency in culture.Both light and prolonging cultural time could reduce the transmission efficiency,but the effect of light was more efficient.No dsRNA segments were found to be loss after 30 generations subculture,indicating that dsRNA could transmitted stably through subculture.Vegetative incompatibility was a barrier for the transfer of dsRNA from one isolate to another,and hypovirulence conversion reduced as the number of different VC genes between donor and recipient isolates increased.

As for drying the thick timber of Schima superba, the drying time is longer while using a normal temperature drying technology. By means of organically combining normal temperature drying with normal pressure superheated steam drying, not only could the drying time be reduce but drying quality was improved by the new technology. The key technology is controling temperature and humidity appropriately when drying technology was changed from normal pressure superheated steam to normal temperature.