In experimental region, the runoff coefficient and soild runoff are only 0.074% and 0.902t/ha·a. The total amount of input nutrient from precipitation is 69.941 kg/ha·a, meanwhile the runoff output including soild runoff amounted to 29.143kg/ha·a, consequently the net increment in nutrient in this ecosystem made up 58.33% of the total input nutrient. In a certain period, the organic matter returned to the ecosystem is 985.35k/g ha·a, the loss of it from soil is 24.02kg/ha·a, thus the net increase of it will be about 41 times as much as the loss. The average utilization efficiency of radiant energy will be 4.64%. In a 5-year-old Cunninghamia lanceolata ecosystem, biomass and nutrient accumulation will amount to 51.6t/ha and 1078.704kg/ha respectively.

The main forest plants within the vegetation and soil zone of DaQing Mountain have been divided into three types, namely grass, shrub and tree, as well as into different families and genera. The suitability to their distribution site, and the relation of chemical composition and soil fertility have been studied by analysing general character and specific property of individual habitat. It is also shown their yield in such kind of soil, parent material and rock briefly.

Root-rot of tung-oil tree caused by Fusarium solani f. sp aleuritidis Chen et xiao is a new root disease. The causative fungi mainly intrude into the root hairs and infect the lateral roots, thus causing root-rot and damaging the tree to death. The number of peroxidase isozymes decreased with the increase of severity of the disease, so that it can be taken as the intrinsic "biochemical symptom" of the infected tree. Within a year, four developmental stages of the disease were observed. In order to forecast the epidemic trend of disease, a simulated model of partial ifferential regression equation has been assembled:Y=0.623+0.457x₁-0.391x₂-0.02x₃+0.005x₄ A better result in application could be achieved when this model was used for forecasting.

Diameter is the main parameter of the drums for forestry winches. Based on the established principles the matching relation between diameters of drums and cables has been studied. Accoding to the utilization grade and loading state of forestry winches, and to the structure and diameters of cables, a table of the matching relation between diameters of drums and cables has been given. The theoretical basis of design and the conditions of reasonadle application have been put forward for the drums of forestry winches.

Hebei poplar is a type of Populus tornentosa Carr. Width of growth rings and fiber morphology were determined. The variations in fiber length related to tree type, growth rings and positions in stem from centre to circumference and base to top. Mean value of more 1.50mm fiber length was found in a type of Yi County, Hebei province in China. It is the maximum length here been recorded for poplar. Results showed that there is a regular increase in fiber length with age of tree. Fiber length increases rapidly at young stage, the maximum length is reached in about 12—14 year, afterwards becomes stable. The fiber length (y)-age (x) relation is expressed as y=1.0490+0.0377x-0.0006x². It's favour the species as a valuable fiber source for some speciality pulpwood species and other fiber industry.

The experimental resuts of the air permeability, moisture diffusion below the fiber saturation point, adsorption and absorption of water, density, shrinkage and fine structure of the Paulownia genus woods were given in this paper. It was demonstrated that PauIownia wood has permeable and diffusive path for fluid as the other tree species, the movement of fluid through Paulownia wood is by the general mechanism for the fluid permeability and diffusion of wood, and the impregnation and drying rating with fluid or heating of Paulownia wood are moderate. Paulownia wood would not have the ability to resist water, but owing to its low density the percentage of shrinkage or swelling of Paulownia wood is comparatively small, so checks will not be often found in a chest made of Paulownia wood, which is considered with good hermetic seal, and the Paulownia wood has been misunderedstood to have some resistance against water.

Wood surfaces are very heterogeneous in nature and variable in the degree of roughness and porosity due to cutting of wood cells. They are usually in a dynamic state, changing with their environmental conditions. The wood surface properties or characteristics will thus inevitably subject to the effect of bondability. So the modification of veneer surface becomes an improtant research problem in the area of wood procession. In this investigation, poplar wood veneers were treated with a specially prepared water soluble melamine compound BL-M expected to be acting as a surface modifying/bridging agent. BL-M not only can crosslink to the hydroxyl groups on the wood surface but also can act with the urea-formaldehyde forming a bridge between the wood surface and the glue. Expermental resuits reveal ed that the gluing strength was found obviously enhanced, the quantity of adhesive applied was reduced about 25-30% and the formation of fuzzy grain on poplar wood surface was greatly checked. The application of this wood surface modification method would be expected to be feasible both technically and economically in the manufacturing of plywood.

In this summa, the state-of-the-art in sampling technique of insect populations are reviewed. The theory and practice of the sampling technique for insect populations were summarised, On sampling for estimating population abundance, the sampling scheme and data analysis, selection of sample unit, calculation of optimum sample size and simplified estimation method (estimating population defisity from relationship between zeroquardt frequence & population density) were reviewed respectively. Also the Risk Decision Sampling (Sequential Sampling) and Simpli-fied Sequential sampling (Presence-Absence Sequential Sampling) were approached.

The forest site classification, assesment and its application are the scientific foundations for silviculture and forest management. The paper considers that the forest site classification system in China undoubtty includes the job of site regionaligation for, in fact, the units of site classification are the same units for site regionalization. The principles for establishment of the system and the units of the system are discribed. A scheme of the forest site classification system in China involved 3 site regions, 17 site zones, 55 site areas and 163 site subareas is provided.

This article is based on forest trials. It shows that rainfall through forest canopy makes up 82.1—86.3% of rainfall out of forest, interception of canopy and stemflow 11.7—15.0%, 0.5—5.0% respectively in the northeast mountains and middle land of Guangxi. The rules of three kinds of rainfall in various forest, and its linear equations have been worked out. It provides a simple method for studying rainfall balance, substance circulation and water conservation in different forest ecosystems.

In nitrate reductase extracting solution, we added excess amount of polyclar AT, and decreased the pH to 7.0, correspondently increased the pH's of the other substrates, thus made the final pH of the reaction system in the range of 7.6—7.8. It was shown that with the treatment of Zn(AC)₂ and PMS to get rid of the excess NADH, factors interfering in nitrite coloration, could be eliminated from this reaction. The inductive conditions of NR and some enzymological characteristics of it have also been studied. Thus a stable and feasible method for the measurement of nitrate reductase activity in vitro in populus leaves has been established.

No. 244 and No. 5 open-pollinated seeds of Chinese fir (Cunninghamia lanceolata) collected from a primary seed orchard were used as the test material, for studying the effect of nitrogen metabolism on seed vigor of during germination (including germination speed, seedling weight, content of free amino acids and protein, etc.), seventeen kinds of free amino acids of Chinese fir seeds, which were not changed during germination but the content were changed constantly, were determined and analysed. Dry seeds used in treatments soaked in 2% NH₄Cl solution for 30 minutes at 40℃. It was shown that germination speed, contents of 5 kinds of free amino acids and embryo protein, etc, during the germination were higher than that in control. In addition, contents of free amino acids in endosperm and embryo of the highvigor seeds during germination were higher than those in low ones.