Based on the investigations of root parameters and soil physical properties, the improving effects of soil physical properties by the roots in different depth of soil in Chinese pine plantation and their interaction have beenfirst quantitatively demonstrated in this paper. The results show that theeffects of roots to improve soil physical properties are consistent with thedistributing rule of effective root density (fibrous less than 1mm in diameter) in soil profile, which follows the decreasing law of exponential function. The vertical changes of roots in improving the soil physical propertiescan be divided into 4 obvious areas of soil layers, and the effects of rootson improving soil physical properties corelate more closely with effective rootdensity than with root weight, and which show a learn positive relation ata significant level (p<0.001). Therefore, an effective model of improvingsoil physical properties by the roots of Chinese pine plantation is established.The value of the model is to plain the mechanism of stabilizing soil structure by roots and to evaluate the effectiveness of roots for improving the physical properties of soil.

From 1984 to 1990, the main hydrological factors, including precipitation, interception of canopy, stemflow, soil moisture, runoff and nutrient content in various water, were measured in the 22-year-old plantations of Cunninghamia lanceolata and Pinus massoniana in Fenyi county, Jiangxi pro-vince. The results indicated that the rate of canopy interception was about10.20-17.56%, the stemflow rate was 0.98-1.40%. The soil layers of theplantations were thinner, and water contents of soil were lower, physicalcharacters of hydrology worse, the properties of penetating and reservingwater less. The amount of runoff in forest land was lower, and most of itwa surface flow. The amount of nutrient input with rainfall in forest landwas more than the amount of runoff output. The nutrients of runfall inforest and leaching nutrients (from runoff account for 45-53% of the totalreducing nutrients. ), and the amounts of leaching K, Mg and N nutrientsto the soil of plantation were more than those of litterfall return.

Diurnal growth rates of stem elongation and leaf area of 7 1-year-old paulownia clones, were observed at early growth stage (June 15th-18th),middle growth stage (August 2nd-4th) and late growth stage(August 28th-31th,1991) respectively in the nursery of Yenzhou county,Shandong province.The results show that the major meteorological factors affecting the stemelongation growth rate were arranged the following sequence: relative humi-dity and temperature in early and middle stage, temperature and illuminationin late stage, affecting the growth rate of leaf area were relation humidity,temperature and illumination in early stage, temperature and illumination inboth middle and late stage. The peak values of both stem elongation and leafarea growth rate are double-peak curves. Their peak values appear at 18:00-24:00 and 12:00-18:00 respectiveiy. Each of the 7 clones has a differentdiural and seasonal growth rhythm, based on which, they may be classifiedinto several different growth types. The results of ths research provide method and basis for the comparative study on the ecological and physiological characterisics of Paulownia genus.

This paper reports on the survey of distribution patterns of the PristiPhora erichsonii (Htg), deals with the sampling methods and techniques and the predication and forecast of the occurring time and amount. What we hadobtained from the researches has been widely used in the integrate controlof Pristiphora erichsonii (Htg) and proved effective. We have consultedAmerican Dialog system through connecting our computer with it, but wehave not found any similar report.

The experiments to study the effect of defoliation of Pinus tabulaformis (intensity, season and needle age) on photosynthesis, transpiration, chloro-phyll content, starch and soluble sugar content, tree growth and its resistanceto Dendrolimus spectabilis were carried out. The results show that the 30%defoliation rate is able to enhence the resistance of trees to the pest insect.After larvae of D. spectabilis being fed by the needles, the growth rate ofweight decreases obviously. It has been proved that the principal stored nutri-tional substance is fat, and the storage organ is needle. The nutritionalproduction and storage in current needles surpass that in old ones. The shootgrowth is smaller and the tree vigor, photosynthesis and transpiration inpines defoliated the current needles are weaker than that defoliated the oldones. By using the current needles to feed on larvae of Dendrolimus specta-bilis, the larvae grow more rapidly. For the purpose of increasing the treevigor and resistance, it is reuired that current needles must be well preserved. The young larvae of D. spectabilis attack mainly the current needles.The larvae fed on current needles have lower mortality and gain greater weight than those fed on old needles. In order to protect current needlesand tree vigor, it is urgent to control the young larvae of D. spectabilis ofthe new generation. Based on the experiments the strategy to control the Dendrolimus in North China has been put forwared.

In the laboratory, the survival and growth of the larvae of Anoplophora nobilis reared in 6 sorts of artificial diets were studied. The results show that the larval stage of the larvae reared with natural diet was of 545.8 daysand the life circle was of 2 years. Whereas the larvae reared with artificialdiet have a life circle of 1 year, a.mean larvae stage of 254.5 days with theshortest of 240 days, and a survivial ratio of 86.2%: The pupal body weightwas increasted; The adults females laid much more eggs and the life spanwas long. The best proportion of No. IV artificial diet (casein 22.5g, sucrose 12.5g,cellulose 509, soybean powder 20g, distilled water 300ml, 4mol/L KOH 1ml,agar 5g, chloride 0.5g, vitamin C 2g, powder of bark of Populus dakuane-nsis Hsu 70g, benzoic acid 0.6g, sorbic acid 1g methyl P-hydroxybenzoc 1g,Wesson's salt mixture 5g, Vandrerzant's vitamin mixture just the rightamount 5ml) was selected by means of orthogonaldesign. The diets with different compositions influence not only e survivial ratio and growth, but also the metabolism of substances and energy of the larvae apparently.

A theoretical equation discribing the self-thinning laws for even-aged pure stands is derived. The equation summarizes self-thinning laws forvarious stocking stands. A series of growth tables of unthinned even-agedstands in relation to initial densities can be obtained by using both of theself-thinning equation and a basal area growth model. The well-knownself-thinning law for fullstocking stand is a special case of the equation asshown in this paper. An example illustrates an algorithm of stand growthtables and confirms the relationship between the self-thinning rate and thestand density.

The article measures the gravity center locations of tree stems with cable crane, the species of tree stems including korean pine, drangon spruce, faber fir, linden, poplar, birch, elm, etc. . It analyses and determines statistically the varing laws and limits of tree stem gravity center locations withcomputer.

This paper presented types and mechanisms of the compressible fluid such as air flow through wood. The slip flow and factors affecting the compressible fluid flow through spruce (Picea jezoensis var. komarovii) and pine(Pinus koraensis) woods along grain direction were measured over a rangeof the reciprocal average pressure from 1.4 to 48 atm^-1. The slip flow wasobserved in the air permeability of woods of the two species mentioned above,however, the slip flow component of spruce wood was higher than thatof pine. The slip flow percentage of viscous flow (K_S/K_T%) and the ratio ofspecific superficial air permeability to the true permeability (K_G/K_T) at 0.5atm, as well as the slip flow factor b were calculated as 69.39%, 1.69 and0.356 atm respectively for spruce wood and 37.64%1.36 and 0. 197 atm for pine.The slip flow was inversly proportional to effective capillary radius of woodtrue permeability and average air pressure.

The investigation of basic information on germplasm resource of Hippophae rhamnoides in China has important significance.In the autumn of 1988,the character variations of Hippophae rhamnoides and their correlation hadbeen investigated in Xinglongshan Nature Reserve in Gansu province, e. g.tree shap, branching ability, number of thorns, length and width of leaves,leaf density, fruit color, fruit shap, fruit diameter, weight per 100 fruitsin fresh, weight per 1000 kernels of seed. Main parameters of various variationtime-space structure and the multiformity of Hippophae rhamnoides populationin Xinglogshan Nature Reserve were discribed.

The aim of this study was to control the young larvae of Atrijuglous hetaohei in the walnut fruits. A high pressure injector was used to inject systemical insecticides into the tree trunk and the insecticides were transported to the fruits by the tree fluids. Based on the dynamics of insecticides in thefruits, its effective period and the peak of adult emergence, the best timefor application and the proper dose of insecticides were decided. Once a yearto use this method, a mortality over 80% could be reached. This methodnot only can save time and labour but also is safe to natural enemies andenvironment, meanwhile it can not be affected by climate. No phytotoxicitieswere found and the residues were below the acceptable level.

A new measuring tool is developed by appling laser technique for forest survey, which has three main functions i. e. visible light direction guidan-ce, measuring distance and horizontal distance measuring by slope measuring.This compass is consisted of two parts, a projecting system and a receivingsystem. The red laser beam is shot from the projecting system, which canset up the visible direction line of fixed position in the forest surroundings,and then the operators can fell trees along the direction. The laser beam isseparated into two beams by a semi-wedge lens, there is a fixed angle bet-ween the two beams, the actual value of measured distance will be showndirectly on the receiving pole. The reading will be the value of a inclinedistance when the receiving pole is vertical to the horizontal plane, and thevalue of horizontal distance when it is vertical to the slope plane. From nowon, the horizontal distance of a slope plane can be obtained directly withoutany conversion of incline distance sin he receiving pole can be vertical to incline plane with the help of lens hood and orientation device.

Based on the stem form exponent of Chinese fir trees, the following calculating formulas of tree-length volume table were derived for this tree species: V_2.8=0.000044886d_2.8²(L+3.686/lgd_2.8) (d_2.8≤14cm) V_2.8=0.000034683d_2.8²(L+8.158/lgd_2.8) (d_2.8>14cm)The precision of stree-length volume calculated from these formulas accordedwith the productive demands by practical measurement test, which may pro-vide reference for drawing up tree-length volume table of other tree species,and which can also form dibasic stem commercial volume table. Therefcr anew simple and convenient method can be provided for tree survey table inthis paper.

The wood adsorptive water is a multi-dielectric relaxation time system.The relationship detween the chart of dielectric relaxation time and the amount of adsorptive water was established according to the theorires of Fouss-Kirkwood and Ferry in the arricle. The distribution mechanism of dielectricrelaxation time of the wood-adsorptive water was discussed. The distribution of dielectric relaxation time of wood-adsorptive waterwere consisted with the theories of Fouss-Kirkwood and Ferry. The distributionof dielectric relaxation time moved to the short time domain as the amountof adsorptive water increased. By applying Fouss-Kirkwood's theory it wasfound that the distribution parameter a of distribution relaxation time wasproportional to the moisture content φ, i. e. : α=(8.33φ+1.94)·10^-1 φ≤27.2%

The nature of Tctracentron sinense MWL has been characterized by chemical analysis, GC, IR, ¹HNMR and ¹³CNMR spectroscopy, It was found that T. sinense MWL is of guaiacylsyringyl type. The main linkage between stru-ctural units β-O-4 aryl ether bond. The quantities of β-O-4 and 5-5 bondwere 0.53/C₉ and 0.06/C₉ and the aliphatic and phenolic hydroxyl contents are1.11/C₉ and 0.30/C₉, respectively. The OCH₃ content estimated by ¹³CNMRwas 1.14/C₉, which was consistent with chemical analysis (1.11/C₉). The con-densation degree of MWL was 0.51/C₉.

This paper studied on the structural and physical properties of Amur linden thinned lumber and compared with nature wood. The difference of haracteristics was analysesed, then high temperature drying scadule wasmade. The process of drying technology and the effect of high temperatureon the strength and shinkage properties was studied.