The heat sum for male catkins ripening of Pinus tabulaeformis Carr., and the daily and hourly changes of pollen density during pollen shedding period in consideration of climite factors were studied in the seed orchard for three successive years (1984—1986). More attention was paid to transporation and dispersal features of pollen inside and outside the seed orchard in the mountainous area. Some ideas of establishment and management of seed orchards have been put forward on the basis of the observation.

This paper, based on a way experimented in the open and windtunnel, puts forward a new index, X_i (a ratio of the average gap between the crown of one tree and the other to average height of the belts), which can evaluate the effect of shelterbelts. Research has shown that X_i is useful for planning and designing shelterbelts and can also judge the sheltering effect of belts growing in the fields. The protected character and mechanism of three types of belts are also studied in the paper. The results are briefly summarized as follows:1. The influence range of different types of belts extends about 4H in the vertical range and 50H in the horizontal range. The distance where wind speed reductions are still at least 20 per cent occurs 18.5H behind belts with a permeability of 35 per cent. The value of wind speed in the lee of belts is closely related with turbulence (r=-0.94).2. X_i is a important index for expressing the effect of the belts on air flow as well as permeability. The optimum X_i for each row in the belts having 1-row to 8-rows was given in the paper.

The relationship between 108 factors of atmospherical circulation & sea temperature and the outbreak of the pine caterpillar (Dendrolimus punctatus Walker) over a large region is analysised by stepwise discriminant analysis, and the predicting model is established. The model not only gets 96% accuracy in back-prediction but also a correct prediction for the recent four years.

The experiment was carried out in the pine plantation of Longshan forest farm in Zhejiang Province from March of 1983 to April of 1985. The damage caused by the pine caterpillar was simulated by artificial defoliation of the pine tree of different age classes in two kinds of soil conditions and under four seasonal periods. The orthogonal regression design was adopted in the experiment and data was analized by stepwise regression method. The results shown that in the first year after defoliation, the effect of defoliation on wood volume is less than the age classes of tree, i. e. the growth rate is regulated by tree itself. The relation between wood volume losses and needle losses is not a simple linear relation but rather a curved regression. Two years after defoliation, the effect of defoliation is not evident.

The purpose of this study was to determine if initial spacing and thinning intensity had effects on wood anatomical and physico-mechanical properties of Chinesefir (Cunninghamia lanceolata (Lamb.) Hook.), and if there existed correlations between them.36 trees, about 20 years old, were selected in 1983 from X, Tian tree farm of Anhui Province in eastern China. There are 3 experimental stands which have different initial spacings (3600, 4500, 6000 stems/ha, separately). In 1974, these stands were thinned with 5 thinning intensities (thinning weight according to stems/ha, was 0, 20, 30, 40, 50 percent in turn).Statistical analysis indicated that initial spacing and thinning intensity had significant effects on traceid length, ring width, latewood percentage, basic density and radial, tengential and volumetric shrinkage (P<1%), so did thinning intensity on compressive strength parallel to the grain, rupture strength and modulus of elasticity (P<1%) as well. Effects of initial spacing on these 3 mechanical properties were not significant.5 multiple regression equations were founded between silvicultural practices (initial spacing and thinming intensity) and wood properties (latewood percentage, basic density, compressive strength parallel to the grain, rupture strength and modulus of elasticity). There suggested that proper application of silvicultural practices would improve wood properties.

This paper reports on the trabeculae that are presented in tracheids and axial parenchyma of secondary xylem of 13 wood species. They are belonged to 8 genera and 4 families of Gymnospermae in China. The morphological characteristics and abnormal types of trabeculae in 13. wood species were observed and generalized 7 abnormal types with scanning electron microscopy. They are abnormal type 1— trabeculae with pantial thicked or sharp deficiency in wall deposition, abnormal type 2—discontinuous or break trabeculae, abnormal type 3—multiserial trabeculae in a series of cells or individual cell, abnormal type 4— trabeculae merged with radial wall, abnormal type 5—plank-like trabeculae, abnormal type 6—trabeculae appearing unevenly and not forming a horizontal row in cells, and abnormal type 7—branched trabeculae. Meanwhile, this paper has also discussed their origin and fine structure.

This paper is an epitome of the comprehensive report on the earlier-stage study on the forestry in 2000. This study aiming at seeking different ways for forestry construction to serve the overall development of the society discusses and proves the assigned subject that cultivation of forest resources is a major programme of fundamental importance in forestry construction, and expounds the basic viewpoints in the study such as to study the development of forest resources from the viewpoints of entirety, interrelation and development, and to study the construction of forest resourccs from the viewpoint of broadening sources of income and reducing expenditure. Starting from these viewpoints, we carried out a quantitative calculation on the developing tendency of the forest resources in our country and drew an outline of long-term forestry development in our country with concentrated efforts on exploring various constructive plans to put an end to the decline of the resources for selective discussions and for final selection by policymakers. We also put forward some opinions on the later-stage work—the guideline for the study on the strategy of forestry development.

It ought to be established an unique site classification system of China according to the background of physical geography and the heterogeneity of regions in China.It has been known that there are the difference of heat on the latitude zonal variation as weel as the difference of humidity, geology and topography on the non-zonal variation in the natural condition of China. Especially, the difference of geology and topography is an important basis for site classification in mountainous regions.Site classification is the one of being controlled step by step, and its grades are determined by the different leading factors and are used for different objects. Afforestation division is carried out by the principle of environmental heterogeneith among regions on a large scale, namely, the difference of water, heat and huge topography as well as the difference of their secondary grades;Site classification is determined according to topography of large, medium and small site, nature of rock, quantitative and qualitative factors of soil.Site classification and afforestation division of China must be a system composed of five grade unites, they are:Afforestation region Afforestation province Site type district Site type group Site type

In accordance with the data of annual volume increments of 99 trees, 220 year-old Korean pine, the age groups of natural Korean pine forests are studied and analysed by the method of category assembling. The results are as follows: young forests, 1—80 years;middle age forests, 81—140 years; near mature forests, 141—160 years; mature forests, 161—200 years;over mature forests, over 201 years.Through variance analysis and multi-layered comparison, it shows that the differences of annual volume increments among the age groups are significant, and it is demonstrated that the abormentioned standard is scientific and reasonable. Perhaps this standard is better than that in the"some technical rules of investigating forest resources" issued by the Ministry of Forestry of China in 1982.

In this paper, the author does not agree with both Prof. Zhou's dedection and Prof. Zhang's opinion on the fomulaPn=P₁/n²,and Thinks the formula should be instead of either P_n=P₁/n² or P_n=P₁/n

The endogenous cytokinins in the sprouts of Chinese fir (Cunnunghamia lancealata Hook.) were isolated and qualitatively identified. Three groups of sprout samples differed in size (i. e., initial sprouts,≤0.5cm in length: bigger unfolding sprouts, 0.51—1.50 cm in length: foliaceous sprouts, 1.51—3.00cm in length) were treated with 95% alcohol and then purified by strong cation exchange resin Dowex 50. The extracts were isolated by thin-layer chromatography with silica gel GF254 and gas chromatography as well, and the fractions in those samples were qualitatively verified by means of gas chromatography combined with mass spectrometry as compared to the standard samples of pure compounds, with the result that three kinds of cytokinins and also adenine in Chinese fir sprouts were tentatively identified.By thin-layer chromatography on the silica gel plane there were several drab spots of different shades, among which the deeper one was more active biologically and manifested itself a clear peak on gas chromatogram. In the light of qualitative verification it turned out that the initial sprout contained more precursor of cytokinins—adenine than the bigger unfolding one while the latter had more zeatin than the former. As for foliaceous sprout there were more isopentenyladenine in its contents, but none of adenine or zeatin had been detected. It will be seen from this that in the growing process of Chinese fir sprouts the kinds and contents of endogenous cytokinins are continuously changing following a certain pattern of growth and decline.

It is very important to select carbon and nitrogen sources for isolating the endophytes from nodules of actinorhizal plants which are nonlegumen. Tween homologues, including Span, may be able to become a good C-source in the isolation and cultivation of Frankia species. Some strains showed better behaviour of growth on pyruvic acid than on propionic acid currently used. It was noticed that vitality of the inoculation should be kept in the procedures of isolation. It was also found that simple and fast techniques of inoculation were more successful than those with complex procedures. The range of tested concentrations of ABA and phenolic compounds didn't obviously inhibit Frankia strains from their growth and isolation. Actinorhizal endophytes could be isolated from the nodules in late spring, summer, autumn, and unisolated in the winter. Fresh nodules should be selected for isolationtobe successful. pH value was not a critical fact in the procedures of isolation.

From the diseased larvae of poplar and willow insect pests four viruses, i, e, Latoia hilarat NPV, Trabala vishnou gigantina NPV, Bhima idiota NPV, Pristphora sp. NPV of midgut type, were isolatad.

This paper introduces an identification key system of Bacillus thuringiensis subspecies with IBM PC/XT microcomputer, by means of CCDOS, and applying DBASEIIprocedure. According to biochemical characters and esterase types, 29 Bacillus thuringiensis subspecies are keyed. The system works on conversitional made, and the results are displayed in Chinese. The program is easy to operate.

The larva of Anoplophora nobilis is the most destructive stem borer of poplar. Different degree of resistance can be observed in various poplar species. Experimental results have indicated that resistance is related to the quantity of soluble sugars and phenlic compounds contained in the tree. The resistance to the pest is sufficiently high with a lower proportion of soluble sugars and tannic acid. It is worth noting that the eating habit of the pest will be altered by the presence or absence of gallic acid. The results provide theoretical basis for selecting poplar trees with a strong resistance to A. nobilis.

Since 1981 we apply fast neutron from an americuurn-beryllium source to radiate the white wax seale's eggs for increasing the white wax production. This paper gives a brief account obtained in expermentation in 1984 in County Emei of Sichuan Province. The experiment showed that an average increase of 22.22%, 29.63% and 21.6% white wax for every 1kg of white wax scale seed after applied the following neutron flux to radiate the white wax seale's eggs: A=1.2×10⁶n/cm², B=3×10⁵n./cm², C=7.62×10⁴n/cm².

Phalanta phalantha Drury is an important defoliator of Homalium hainanense. It has 12 to 13 overlapping generations per year in Hainan Island. It is likely that the pest will come the disaster in May, if the rainfall is less than ordinary in dry season. The larvae like to dwell on the back of the leaves. The character of the imago is of flaping its wings unceasingly. The stock with 5ppm permethrin or 90% crystal Trichlorphon diluted with 2000 to 3000 times of water can be used for the chemical control. The means of forestry is to cultivate the mixed crop, and clear the FlacOurtia indica round the forestry.

So far as we know, 8 species of Lyctidae were reported in China: Lyctus brunneus (Stephens), L. africanus Lesne, L. sinensis Lesne, L. linearis (Goeze), Minthea rugieollis (Walker), Lyctoxylon japonum Reitter. Trogoxylon impressum Comdi and T. aequale (Walleston) S. jago. This paper deals with susceptibility of chinese hardwoods to powder-post beetles and presents a list of attacked woods which, include 39 families 103 genuses 168 species of tree but bamboo and rattan. Sapwood which contains an adequate amount of starch is attacked. Moreover it with large pore is more liable to infestation. The diameter of wood-vessels of 89.3% species of wood susceptible is more than 100μm. Minimum pore (<25.μm) woods and coniferous woods are not attacked, such as Aquifoliaceae. Theaceae. Hamamelidacece and Symplocaceae.Control methods:1. To remove the starch in sapwood, freshly felled wood or saw-lumber may be submerged in water for one year.2. Preventive treatment with boric acid or borax or spray with permethrin.3. Fumigation with methyl bromide (CH₃Br) or sulphuryl fluoridc (F₂O₂S) at 40g/m³4. Heating sterilisation with wood kiln.

A method for calculating average skidding cost and optimal road and landing spacing under linear and non-linear conditions is presented. Higher mathematics, tabular solutions, calculation of average skidding distances and assumptions of skidding costs which are directly proportional to distance are not necessary. With micro-computers, simple programs can be written to directly sum up the skidding costs in an elementary, easy to follow procedure. Examples for radial and right-angle skidding patterns, and situations where uphill skidding costs differ from downhill skidding costs are presented.