The cubic and plane structural shelterbelt equations expresing relation between sparsity and ventilation coefficient were α = β^0.4 and α = β^0.95 respectively, which were given by using data obtaibed from field observation and wind tunnel experiment. The resistances of seven wind tunnel model shelterbelts were determined with platform balance. The resistance coefficient was C_α = l6.3 (1-α)^0.55 when the shelterbelt structure was expressed as ventilation, and which was C_β = 14.0 when shelterbelt structure was expressed as sparisity.

The data obtained from 41 survey plots within the range of Shanxi preovince, e. g. growth increment, characters of cone, needle and seed, were analyzed in the aspects of single correlation and multiple regression analysis. The results indicated that the differences in 9 characters among stands were significant at the 0.01 level, some characters correlated with longitude and latitude, climatic factors. The general tendency was that the needle numbers of a cluster increased as the climate become drier and colder from south to north, which was on the variation pattern of cline, and the cone-scale numbers also increased gradually, There was also a tendency to increase annual increment from northeast to southwest, especially there was a strong positive correlation between diameter increment and altitude. In addition, the multiple regression analysis results showed latitude, annual mean temperature, and mean temperature in Junuary were the main factors affecting increment, while mean temperature in July and latitude influence the change in needle numbers of a cluster mainly. In the meantime, the main ecological factors which influence variation have been screened out

In this paper, taking the natural secondary forest in the east mountains of Liaoning as the object of study, three-dimensional management models of forest were established according to the basic ideas of ecological forestry and ecological theory. The aspects, such as structure and function of models, changes in forest ecological factors and stand factors after establishing these models, growth and development status of various economic plants,as well as the artificial manage want measures of main economic animals and plants in models, and so on, were investigated and analysed. The results indicated: it was possible to add in various economic components of animals and plants together with the comprehensive managements of natural secondary forest so as to establish threedimensional management models with multi-species and multi-stratum, which have prevailing ecological, economic and social benefit.

Cryptotympana atrata (Fabr. ) is an important branch-boring pest of poplar, elms, apple etc. Observations have shown that five years are required for the pest to complete a generation. The pest overwinters as larva in the soil and as egg in the branch. The adult occurs from early July to mid-August. Oviposition begins in mid-July; the peak of egg-laying is in mid-August; the egg period is from 260 to 340 days. The longevity of the adult is from 45 to 60 days. The sex ratio is 1:1. The adult male likes to sing. The adults have the characteristics of cybotaxis and the sociality} the space distribution pattern of the adult in the forest coincides with the aggregated negative binomial distribution. The effective control measures include the selection of the varieties of poplar resistant to the damage of the cicadj cutting branches with eggs in winter; dusting or spraying chemical pesticides on the host tree crown during oviposition period and on the forest floor during nymphal emerging period, and watering the soil with ammonia water in late June and interpianting corn young tree.

In this paper, the author demonstrates that the maximale erroe of deflection for cubic solution of perturbational algorithm is near the lower fulcrum. This paper puts the formula of calulate the maximale erroe of a deflection and the erroe of level tension. Based on the above work, the discussion was made of the precision for perturbational algorithm of a cableway. And, besides, this paper puts the formulas of calulate the absolute erroe of a detection for once and cubic solution of perturbational algorithm, so that the height is under control in the production.

The gum-producing life of rudder tree (Hevea bresiliensis (Hbk.) Muell. -Arg. ) is 25-30 years. In China, about 800,000m³ rubber wood will be produced each year and needed to be treated by preservatives to ensure wood products free from biodegradation. Although the complex of boron phenol has been used for long time, it contains Na-pcp which is very poisonous to human being and has been banned by some countries, A new wood preservative TWP which is a complex of three water soluble preservatives was developed at the Research Institute of Tropical Forestry,CAF with the advantages of high effec tiveness, broad spectrum, long lasting action and low toxicity to human. Results from the laboratory toxic tests of TWP showed that 1) in controlling decay fungus (Coriolus versicolor (L. ex Fr.) Quel) the threshold retention is at 2.2-3.2kg/m³, 2) in controlling bostrychid powder-post beetle(Heterobostrychus aeqalis(Waterhouse)) the retention of killing egg-laying and larval is at 1.0kg /m³, 3) in controlling bluestain fungus (Botryodiplodia theobromae Pat.) and mixed mould fungi, the inhibition concentration is at 1.0% and 1.5-2.0% respectively, and 4) TWP is safe in use to human, animals and environment. On acute male mouse LD₍₅₀₎ of TWP is at 1, 301 mg/kg. Application trials of TWP were carried out in four wood factories in 1988-1990. The rubber green sawn can be successfully treated by full-cell or oscillating pressure processes with 2.0-2.5% TWP, Average net retention of TWP is at 4_-⁺0.7kg/m³. The preservation effect of the TWP is better than emulsion of MBT and TCMTB at concentration of 2.0%. It is considered that TWP is a rubber wood preservative of low toxicity and may be instead of the complex of boron phenol.

According to reserching the relation of the forest-resource charatistics and forest-fire, a method is put forward for the first time, which the assessment value of the charateristics of each as size factor is determined first and the assessment value of the potential compartment forest-fire danger is synthetically caculated second. Taking forest experiment station of Jilin Forest Institute as base, the potential compartment forest-fire danger grade map and its concert application have been developed.

The article analyses theoretically three kinds of jaw shapes(horizontal ellipse, circle, verticle ellipse jew shapes) widely used in forest areas of China based on mechanics. Then, using the technology of resistance strain gage and three kinds of jaw shapes same as theoretical jaw shapes, it tests the effects of log grapple's jaw shapes on the grabbing properties under the working condition of grabbing compact pila; the testing items include grabbing force, log volume grabbed, grabbing force/log volume grabbed and "the number of logs blocked" duzing grabbing. The theoretical results correspond with the testing results. The results show that the property of horizontal ellipse jaw shape is better, circle jaw shape's takes second place and vertical ellipse jaw shape's is worse.

In this paper, the combined effects of forest for conservation of water source in the Qilian Mountains have been studied by fixed position observation method of forest ecological system. The results indicate that the Picea crassifolia forest is the best ecological system of water conservation forest over the Qilian Mountaions. Its mechanism for conservation of water supply are given as follows canopy can slow the raindrop splash down to the surface of soil and intercept 25.4 per Cent precipitation, the litter of forest soil is thick;the noncapillary porosity is high, forest soil structure is good, all precipitation are detained in forest soil, the surface runoff does not happen, and it can be decreased by forest vegetation. The forest vegetation can also cut down the foold peak and prolong the runoff time, which plays a role of suppling more water in dry season.

Based on data of 52 temporary sample plots established in a wide range of longitudes 106°17'—121°23'E and latitudes 26°26' — 30°25'N, the growth responses of Cryptomeria jortunei artificial plantation to comprehemsion of geographical topography, edaphic climate, and many environmental factors in stand were studied. The results indicated that the multiple regression equation consisted of 13 variables, including latitude, longitude, altitude, distance to coastal line, slope position, slope azimuth and inclination, soil depth, a layer depth annual mean temperture, annual precipitation, stand age, and stand density, can be used to estimate the average height of trees, DBH, individual stem volume, stand volume and height of dominant tree precisely. The regression models established by 12 variables (excluding stand age) as stated above, or 4(annual mean temperature, annual precipitation, altitude and soil depth) or 3 (latitude, longitude and altitude) can be able to estimate the height, DBH, individual volume of 20-year-old trees, and stand volume and height of dominant trees reliablely.

From the point of water capacity equilibrium view, the study approached the regulation and control effects of artificial water supply on growing mechanism of Populus × Popularis Chon-Lin, and moisture and heat status of soil under different water supply conditions. The results revealed the relationship between water supply and conditions of moisture and heat for Populus × Popularis Chon-Lin plantation growth. During this experiment conducted from years 1984 to 1990, soil elements of moisture and heat, ground water level dynamics, as well as growth increment of forest trees had been observed year by year at regular intervals. The results show that irrigating the artificial plantation of Populus × Popularis Chob-Lin in the dry region of Northwest, the ground water level within plantation growth period could be raised 0.5 to 1.54m, and the status of soil moisture and temperature could be improved effectively.

The paper presents a list of ants collected from Jianfengling tropical forest natural protective region, Hainan Province during 1981—1990. Fourty species belonging to 6 subfamilies are identified, including 2 new records from China: Aenictus javanus Emery, Tetramorium smythi Mayr and a new synonym Dilobocondyla fouqueti Santschi=D. fouqueti Santschi var. lighti Wheeler. The paper also presents a detailed redescription of D. fouqueti and brief descriptions of the morphology, biology and economic importance of some species.

Based on the theory of optimization, the optimal management of Chinese pine caterpillar was studied, using the three kinds of decision method. Firstly, using economic threshold by comparsion of four kinds of sequential sampling,we obtained the optimal decision of sequential sampling——the co-sequential sampling (Gao chunxian, et al 1983) ,the co-sequential sampling can determine whether the Chinese pine caterpillar need control. Secondly, based the above results, we compared ten kinds of control measures.The results of the satic decision show that among the control measures using spraying poisonous ring is the best one, and the results of the dynamic decision show the optimal project is "the spraying poisonous ring", "the spraying poisonous ring", "no control" and "nocontrol" during the larvae climbing down-tree, the larvae climbing uptree, the 5-instar larvae to pupa and the egg to larvae climbing down-tree respectively.

The relative crystallinities in three regions (compression. transition and opposition region) of compression wood of Masson pine (Pinus massoniana) have been determined with the method of X-ray diffraction analysis, and the results of the measurement have been analysed with the theory of thermodynamics; The study showed that the crystallinity distribution in different zones of compression wood follows certain regularities which are caused by the following factors; (1) intrinsic growth mechanism of trees, (2) enviromental temperature of growth, (3) compression and tension state of trees.