An investigation was undertaken in the variations in rooting ability of Larix leptolepis(Sieb.et Zucc.)Gord.using fullsunshine and auto-spray system. The materials used were softwood cuttings which were taken from 10seedlings,at 6.5 year age,of each half-sib families of L.leptolepis and from 140 plants,at 10.5 year age,of two hybrids between L.leptolepis×L.principisrupprechtii Mayr and L.olgensis Henry,respectively.The research results showed that significant phenotypic variations existed in genetic variance,heritability and rooting rates between different families and clones, however,the variations between clones within a family were even more significant than those between families. Therefore,the combined selection based on the performances of both family and clone would be better than that based on family or clone means.Genetic gains could be estimated with combined selection of multitraits.Rooting percentage could be ncreasad by 47.5% through selecting 15% of the best clones other than using the overall mean of 140 individual clones.

The evaluation on site quality was made for plantations of Dendrocalamus giganteus in southwestern Yunnan Province, China,using quantitative modelⅠand systematic cluster analysis.Site types were classified and the present and potential productivities of plantations of D.giganteus were also predicted based on the classification.The sampling method applied to sympodial bamboo forests was also discussed.

Roots and fine roots(<2mm diameter)were sampled periodically from P.tomentosa cutting plantlings grown in cuttingbed, and from plantations of P. tomentosa growing in Central Plains of China.Percentages of VA-mycorrhizal,ectomycorrhizal, dual colonized, and non-mycorrhizal root lengths were determined.The results showed that in primary infections of cutting plantings by mycorrhizal fungi,VA mycorrhizae predominantly occurred in the root system but were then rapidly supplanted by ectomycorrhizae.The negative interactions among VA -and ectomycorrhizal fungi strengthened with ageing of the cutting planttings. History of the afforested area and soil pH-value have an instrictive effect on the negative interactions among the mycorrhizal fungi. On the alkali sand site,the percentage of VA-mycorrhizal root lengths was much more than that on the neutral forest soil site, there was a significantly difference between them.

A number of isolates of Bacillus thuringiensis were obtained from 129forest soil samples at 0-5 cm depth collected from 8 Nature Reserves Chaocha, Dailing, Qiangfoshan, Laoshan,Huangshan, Zijinshan,Wuyishan,and Xishuangbanna) in China. The number of Bacillus and the rate of isolates(% )of Bacillus thuringiensis showed difference in forest soil of distinct Nature Reserves.Calculation of rate of Bacillus thuringiensis to Bacillus in these forest soils also showed difference.These differences have no correlation with soilmoisture,pH, and nurture of forest soil.The isolates of Bacillus thuringiensis were identified. The toxicities of isolates of Bacillus thuringiensis against 6 species insects were determined.

In this paper,a new species of the genus Sinophasma Gunther, from Sichuan Province of China is described. The type specimen is deposited in Beijing Forestry University.Measurements are in mm.Sinophasma curvatum sp.nov. (Figs.1-2)This new species is allied to Sinophasma rugicollis Chen,but easily distinguished by the size being rather small;mesonotum granulated densely;the median part of ninth tergite bend upward from lateral view;the posterior margin of anal segment without deep excision and subgenital plate flat and wider.Female: unknown.Holotype,Jiangjin County, Sichuan Province, July.27,1991, collected by Cheng Jingqiu.Size 40;pronotum 2.2;mesonotum 7.8; 8th abdominal segment 2.0; 9th abdominal segment 3.4;anal segment(10th abdominal segment)1.2;front femora 9.2;intermediate femora 9.4;hind femora 12.8.

The presence or absence of warly layer in the vessel elements and fibres of 182 Chinese woody species from 135 genera belonging to 48 dicotyledonous families were examined using electron microscopy. Warly layers were found to be present in 50 species from 32 genera belonging to 17 families but absent in the remainder.Occurance or nonoccurance, distribution densities,sizes and shapes of the warts are of some value for the classification of families,genera and even species of hardwoods.The results of ultrathin wood sections of two species studied by TEM both revealed the differences between the warts and second walls in electron densities,i.e.the chemical composition difference between them. In addition, the relationship between warly layers and types of perforation and their positions in an annual ring was also discussed. But no significant relationship has been found between the occurance of warty layer and the evolution of xylem in this study.

The effects of chip thickness,knife rake angle,and wood moisture content on cutting resistance were studied with 15 Chinese hardwoods, following the similar studies with 11 Chinese coniferous woods,The discovery on these effects made through the studies with the conifers was further confirmed. Some difference in the effect of wood moisture content was found between conferous woods and hardwoods.

In order to understand the effect of heat treatment upon the collapse. of Eucalyptus wood,moisture contentshrinkage curves are measured and drawn in this paper by means of drying at constant temperature and various humidity for treated and untreated Eucalyptus viminalis、E. tereticornis and E.camaldulensis. The result shows that whether heat treated or not,E. viminalis and E.tereticornis have the typical"collapse pattern"moisture content -shrinkage curve.For heat treated timber of the two species,however,the second stage collapse appears rarely and the whole shrinkage and shrinkage at"shoulder point"are lower than that of untreated timber. Effect of heat treatment is apparent on E.viminalis and E. tereticornis.no effect on E.camaldulensis, This paper has introduced a two stage collapse theory and expounded for the first time that it is inevitable to appear"shoulder point"in the "collapse pattern" moisture content -shrinkage curve,and illustrated the limitation of the"indirect vessel collapse"theory presented by Shin Terazawa

Chemical compositions of Pine wilt diseased wood and sound wood have been researched.It was found that there is no notable difference between soundwood and diseased wood in major componentcellulose, hemicellulo and klason lignin,but content of phenealcohol and ethylether extractive substantially decrease.After pine wood is attacked by Bursaphelenchus xylophilus, the decrease in amount of thylethen extractive of diseased wood is a dominant characteristic.Otherwise there are some difference in chemical components of thylethen extractive and PH value of wood between sound wood and diseased wood. The sound wood and diseased wood are distinguished by colour reaction used proper indicator.

This paper is a general review of the research status of Pinus Kesiya var.Iangbianensis, which naturally occurs in southwestern China with a range of latitude 21°10′24°24′N and longitude 99°05′- 102°30′E.,to summarize the information materials on the taxonomy, floristic geography, biology and ecology, utilization and genetic conservation of the species.A conclusion could be drawn that P. Kesiya var. langbianensis was floristicaly not a substitute species of Pinus Yunnanensis being geographically replaced along ecological qradient. P. Kesiya var. langbianensis is an important tree species in the natural forest, and very closely related to P.Yunnanensis and P. Kesiya in terms of the origin and distribution,therefore, it is suggested that more research should be undertaken with its morphology,genetics and population ecology.

Continuously moving skidders,mainly J-50 tracked skidder and J-80wheeled,are widely used in extracting operations in the forests of northeastern China and result in soil erosion and humus loss which seriously affect stand regeneration and growth of remaining crops.Using Grey Theory an investigation was undertaken to analyze soil compaction and seedling growth in the stands under such a harvesting system.It was found that extracting operation caused less damage to soil structure and less effects on the height growth of seedlings by the use of tracked skidders than wheeled ones.

In the experiments with hybridization between Populus alba × P.tomentosa and p. alba var. pyramidalis,the branches with male flowers were treated with rare earth element solutions at concentrations of 10,50 and 200ppm.The results showed that rare earth treatments increased the germination percentage of fresh pollens and delayed their vitality decline.And rare earth treatment at 200ppm was observed to have the best effects.The female flower oranches were also treated with rare earth solutions at 5,80,200 and 500ppm.The viability of seeds could be maitained for a long time after the treatments.These experiments proved that rare earth treatments could keep the cell membranes intact and slowed down the leakage of metabolities.t was found that the amount of oxygen absorbed by seeds and the vitality of dehydrogenase were inhanced,and the transportation rate of stored substances was speeded up.

The differences in the enzyme activities and chemical properties of the rhizosphere and non rhizosphere soils of Cunninghamia lanceolata were studied.The results showed that(1)pH value was lower in the soil in the rhizosphere than in the nonrhizosphere, while the content of organic matter,total N,total P, inorganic P, organic P, available N, K,Cu and Zn,exchangable Ca and Mg was significantly higher in the rhizosphere soil than in the non-rhizosphere soil at 0.05 or 0.01 level;(2) Acid and neutral phosphatase,urease,invertase,catalase,peroxidase activities were significantly higher in the rhizosphere soil than in the non -rhizosphere soil, and X_R -X_S value was successively 1.44,0.66,0.21,24.92,5.00.1. 01.Except that polyphenol oxidase activity was lower in the rhizosphere than in the non-rhizosphere soils, X_R - X_S value was -6. 80;(3)The effect of the growth of Cunninghamia lanceolata on soil enzyme activity was named "rhizosphere effects".The degree of rhizosphere effects among soil enzyme activities was orderly invertase,urease,catalase, nuotral and acid phosphatase, peroidase, polyphenol oxidase and the R/S values were 3.10,2.74,2.03, 2.01, 1.91, 1. 44, and 0.47respectivelly.

A study was carried out in the natural stands of Populus davidiana in the area of Loess plateau,northwestern China,to observe the hydrological and soil conservative function of litterfall.It was found that the amount of litterfall was the highest in October and the interception rate of litter reached 18.9%.Evaporation of soil water, which was restrained by litter and affected by soil moisture content,was reduced with the increment of the thickness of litter layer in the stands. The occurrence of streamflow varied directly with the thickness of litter layer and negatively with the degree of slope and the streamflow depth.The study also showed that soil loss damping was improved to 83.2% by 1cm thick layer of litter on the ground.the streamflow and sedimentation were increased by 1.66 and 8.15 times,respectively,as the litter was removed from the ground.

The canonical correlation analysis was used to describe the influnce of the enviromental factors on the growth characters of Platycladus orientalis stand in mount Qianfe of Ji'nan. Three topography variables, four soil variables and stand density were selected as enviroment factors. Four growth indices i.e.height,DBH,basal diameter and standing stock were regarded as dependent variables. Three pairs of canonical variables which had significant correlation, but had no correlation between them were:(1)Stand density and positive moisture index in soil, diameter (DBH and basaldiameter);(2)Elevation, standing stock caused by innormal growing;(3) The negative moisture index in soil, standing stock caused by normal growing.The conclusion showed that the stand density,the positive moisture in soil and topography were the major factors influencing the growth marked by diameters,and the growth is not sensitive to the exposure,the gradient,the soil texture and the content of organic matter in soil.It showed the characteristics of barren-enduring and higher adaptability for enviroment of Platycladus orientalis.

The Willow Oyster Scale,Lepidosaphes salicina Borchs.(Homopter:Diaspididae)was studied in the "Three North"Protective Forest of China during 1987 -1990. It has one generation a year and overwinters as egg under the scale in Shenyang. The females lay eggs under the scale about 84 eggs on average.The sex ratio is 0.55 (♀♀/100).The important natural enemies found are the predacious mite,Hemisarcoptes malus (Acari:Hemisarcoptidae),which reduced the pest population by 41.6%;Aphycis proclla (Hymenoptera:Aphelinidae) and Chilocorus kumance(Coleoptera:Coccinellidae).A bufferointmenc insectcide was tested and used for controlling the pest in the field,a 92.2% - 97.2% mortality was obtained after 8 - 20 days.The population density was lowered significantly three years later. The distribution,damage,biology,of the pest were involved.