For analysing and evaluating the soil water features, the periodical soil water measurement and stand investigation were carried out during 1988—1992 in the experimental station of Beijing Forestry University, Ji County, Shanxi Province. The results showed that according to the vertical soil water variation, the soil profile could be divided into three layers, i. e. weak utilization layer, utilization layer and regulatinglayer, and according to the seasonal soil water veriation, the calendar year of soil water condition could be divided into four periods, i. e. consuming period, accumulating period, lowering period and stable period. From the study of soil water effectiveness, it is shown that eddectiveness of northern slope is better than that of southern slope, effectiveness of bare and shrub land is better than that of forest land. A multiple regression equation is proposed to present the relationship between soil water content, frequency of noneffective water and verious stand description factors of black locust and Chinese pine plantation.

Within the boundary of a small watershed covered with Pinus elliottii stand, the cycling process of K, P, Ca, Mg, Zn, Cu, Fe and Mn, including their average budget, accumulation, storage, leaching, return and absorption were studied in 1993—1994.The stand had high productivity(20.349t/hm²·a and 9.408m³/hm²·a)because of its high usage efficiency of mineral elements.The total amount of mineral elements input into the forest was less than that of output from it in 1993—1994.The forest was still on the degenerate state with less return amount and lower cycling efficiency. It is suggested to adjust and control such a forest by some artificial measures such as fertilization and mixed planting with broadleaved tree species.

With the method of the diameter—changeable sampling plots, the dynamic development of a kind of subtropical broadleaved forest was studied in Heishiding, Hongkai County of Guangdong Province. The vertical structure of the forest was divided into 3 stratums: Ⅰ. under 10m; Ⅱ. 10-20m; Ⅲ. over 20m. The density, frequency and domination of tree species in each stratum were investigated. As the results 4 types of species were proposed and characterized: (1) Declining species: Pinus massoniana, Quercus chungii, Castanopsis carlesii; (2) Developing species: Cryptocarya concinna, Syzygium hancei, Neolotsea phanerophlebia; (3) Stable species: Qrmosia pachycarpa, Machilus breviflora; (4) Unstable species: Lithocarpus synbalanos, Sinosideroxylon wightianum.

This test was carried out with Eucalyptus camaldulensis in vitro to study the high frequency and synchronous production of shoot tips. As 6-Benzylam inopurine (BA) (0.5-1.0mg/L), naphthalene acetic acid (NAA) (0.25-0.5 mg/L) in the medium increasing, more shorter shoots with smaller leaves and more shoot tips suitable for being encapsulated were produced. 40mg/L adenine (ADE) with 1.0mg/L BA and 0.5mg/L NAA in the medium has some role in controleing the shoots and leaves growth, and is fitable for the shoot tip production. The synchronous production of shoot tips was realized through the culture on 16 days light then 4 days dark. In three successive subcultures, mean 25 shoot tips per the material area (cm²) per subculture (20 days) were achieved in the semisolid medium. The problem of brown exudate in shoot subculture was also researched. The measure to overcome was released.

A new concept, forest coverage of the optimum forest protective effect(FCFP), is defined, and the theory and methodology to establish the FCFP are presented. On the basis of the given forest areas, the increase of the forest internal quality and the optimization of space distribution pattern have significant gains in protective effects of forest ecological system. The optimization of forest area, quality and space distribution maximize the forest protecting capacity(FPC). A maximum of FPC is regarded as FCFP, but the magnitude of FCFP is affected by a given natural environmental conditions. Based on the data from the region of low mountains and hills in Sichuan Basin, FCFP for districts of middle-low mountains, low mountains, hills, hillocks and plains may reach 57%, 46%, 44%, 31% and 13% respectively.

Based on several ordinary investigations (including west slope, east slope and north slope) and long-term fix-position research of cryo-brown soil under the forests of the north area of Daxing'anling mountain, according to keys to taxonomic classification index of cryo-brown soil, Caocha natural reserve with wide representative characteristic which is in the west slope of the north area of Daxing'anling mountain is selected as the collecting site of cryo-brown soil standard profiles. According to describing standard of the soil profiles, and the soil analysis program and method in laboratory established by "The Research Program of the Chinese Soil Taxonomic Classification", the field collecting soil sample and analyzing soil in laboratory were carried out. The research result discussed about the condition of soil-forming in cryo-brown soil profiles and its basic characteristic, and based on the diagnostic horizon and diagnostic characteristic, studied the problems of the taxonomic classification of cryo-brown soil, and also studied and discussed the diagnostic surface horizon (humus surface horizon and gley surface horizon), diagnostic subsurface horizon (weathering B horizon, argillic horizon, spodic horizon and spodic characteristics) in the diagnostic horizons and the diagnostic characteristics including the freezethaw characteristic, soil moisture regime, soil temperature regime, the content of gravel on the surface to 50 cm soil layer.

The above-ground biomass production, distribution model, nutrients exported and wood quality characteristics of eastern cottonwood were studied in minirotation management systems among the combinations of 3 densities and 3 rotations, The stand, with planting density of 10000 plant·ha^-1 and 3 years rotation, could obtain the hightest biomass production 10.52t·ha^-1·a^-1 for clone I-69 and about 12.00t·ha^-1·a^-1 for clone NL-80351.The economic biomass production for pulp-making was also the hightest in the stand of 10000 plant·ha^-1 and 3-year-rotation, respectively 7.14t·ha·^-1·a^-1 for clone I-69 and 8.47t·ha^-1·a^-1 for clone 8.47t·ha^-1·a^-1. Nutrients exported from the minirotation management systems bear close correlation to the biomass production and distribution model. In the stand of 10000 plant·ha^-1 and 3-year-rotation, the amount of nutrients exported (N, P and K) were 33.97kg·ha^-1·a^-1 for clone I-69 and 38.50kg·ha^-1·a^-1 for clone NL-80351.However, the amount of nutrients exported for producing one metric ton of economic biomass was slightly lower for clone NL-80351 than for clone I-69.The timber produced from the minirotation management systems is a good pulp-making material, but the wood quality of clone I-69 is slightly superior to clone NL-80351.

The vacuoles were for the first time isolated from the mycorrhizal fungi (Amanita muscaria and Cenococcum geophilum) by the polybase, DEAED-dextron, induced lysis of protoplasts. The protoplasts isolated from mycelium cultured in MMNC+P medium for 4-7 days showed considerable vacuolation.The yield of vacuole was in the range of 5-10% of protoplasts. The purity of vacuolar preparation was judged by measuring and comparing soluble cytoplasmic enzyme G6PDH, which indicated that it was not contaminated by the cytoplasm and other cell organelles. The measurement of activities of acid phosphatase and α-mannosidase in equal number of vacuoles and protoplasts revealed that almost all this two enzymes were located in the vacuole, so they might be established as the vacuolar marker enzymes for A. muscaria and C.geophilum.

The sex pheromone plus virus dispenser technique is a type of autodissemination with which pest insect population levels can be controlled by using insect sex pheromone and insect virus. The feasibility of the technique has been confirmed by the experiments in the wind tunnel. The results of the field tests showed that under the conditions of hanging one dispenser for every five Paulownia elongata(S. Y. Hu)trees, traps set up in the centre of the 300m×300m treated plot caught male moths having visited the dispensers and being contaminated by the virus every day during the test period 29. 2% of virgin females set up in the centre of the treated plot were contaminated with the virus by mating with the males. The larval CVNPV disease mortality reached 73. 2% in the larvae emerged from the eggs laid by the contaminated females.Therefore, the field tests demonstrated the feasibility of the sex pheromone plus virus dispenser technique under the field conditions.

The one-dimensional series(1-D series) method was proposed to analyse the population spationtemporal structure. It included one-dimensional series sampling method, single population spatial structure analysis, space-time correlation analysis, and the relationship between space-time analysis and population dynamics forecasting. The result of pine caterpillar(Dendrolimus punctatus W.)sturcture analysis indicated that 1-D series method is much better than classical spatial pattern index methods, the space-time analysis result indicated that 1-D series method is also suitable for analysing population dynamics-spatial diffusion.

The tests of wood properties and pulping experiment were carries out with the 5-year-old Eucalyptus ABL No.12 grown in Guangdong province. With the weighted mean of the BH disc as the unit, the average values of the following properties were: 90μm of tangential diameter of vessels, 16N/mm² of pores number, 15N/mm of rays number, 0.868mm of fibre length, 2.9 μm of fibre wall thickness, 14.0 of vessels percentage, 29.8 of parenchyma percentage, 56.2 of fibre percentage, and 0.577 of basic specific gravity. The radial variation of these properties was investigated. The wood belonged to a medium class of strength, and contained 77.62% of holocellulose and 25.09% of lignin. A pulping experiment of alkali-AQ process showed that it was easy to pulp, with 46.92% of yield of coarse pulp and 73.8% of bleaching degree, and the sheet formation was good, with 4.58kPa. m²/g of burst index and 7.53mN. m²/g of tear index.

The major difficulty in wood variation research is that the objective of the research is of too big size and great complexity. The research with limited range in tree species but greater intensity on the influencing factors is suggested an effective approach to obtain theoretically more abundant and practically more effective results, and a systematic study on wood radial variation patterns with most important afforestation tree species, taking as many influencing factors as possible is considered the relevant point.

Based on the princilpe of hydrological balance, a new method, which is the single-tree water balance periodical measurement method, and a single-tree hydrological equation are established. The metold can be used successfully for measuring the quantities of single-tree transpiration and the forest land evaporation respectively.

DNAs isolated from poplar trees Ⅰ-69(♀)、 Ⅰ-63(♂) and two F1 clones named 34-17 and 34-135 were used as template to detect the polymorphisms by RAPD analysis. Of 200 primers, three primers amplified polymorphic products, and only one of them, OPAD-01 is linked likely to insectresist gene.RAPD analysis of 34-215 (suspective to pests) and 34-188 (resistance to pests) also confirmed the results.