In the protoplast culture of Populus simonii Carr. ,the variations in contents of IAA, GA₃, CTK, ABA four kinds of endogenous hormones in the calli differentiated from four differentiation culture media were determined by the high pressure liquid chromatography method, and the biochemical reactions of nitrogen related to them were also tested. It was shown that there was a great change in the contents and kinds of the endogenous houmones among the calli differentiated from the different media. The treatment which resulted in the higher content and more kinds of CTK, and the higher ratio of CTK/IAA within the calli was favourable to the calli differentiation, whereas if the ABA was contented in calli, the differentiation of the calli was inhibited. During their differentiation process, a mutually exclusive relation between the activity of nitrate reductase(NR) and the amino-N content was found, in the calli with higher differentiation frequancy the NR activity was low, but the amino-N content was high.

Based on the investigation of forest climate and surface runoff for 10 years, the water balance of the Chinese fir forest in the three areas of the northeast low mountains, southeast low mountains, and the middle areas in Guangxi Zhuang Autonomous Region, was studied. The results indicate that the evapotranspiration is the greatest output in the water balance within the three areas, which increased from the northeast area to the southeast area, and then the middle area of Guangxi Region. The infiltration water to soil layer is the second greater output, which has the opposite distribution regulation to the evapotranspiration. The surface runoff is the least, which has the same doatribution regulation as the evapotranspiration. However, there is an exception to the young Chinese fir forest, in which the surface runoff is the largest, the infiltration water to soil layer is the smallest. The best ecological benefit of water resources in the three areas is in the northeast Guangxi Region.

Through Iwao -${\rm{\bar x}}$ regression determine, the spatial distribution on the jujube looper larvae obeys Neyman-A pattern and Poisson distribution, the basic component of the distribution is thick colony. The distribution among colony and intra-colony is random, the area of colony is equal to or less than one tree. Two sets of estimation sampling were advanced, i. e Whole-Tree Sampling and Layer Sampling, the former is advantageous when using random and chessboard sampling, and the formula of theory sampling were presented; the latter can raise sampling efficiency, and reduce sampling cost, and the estimation precision is up to the standard of production and scientific study when it estimates thick of population with lowest layer sampling replacing whole-tree sampling. Finally the sequential sampling dicision models of Iwao were presented.

It was revealed by internal anatomy that the female of Chouioia cunea Yang has a pair of ovaries. Each ovary consists of ovarioles from six to eight. The number of ovarioles sometimes is different in both ovaries even within one individual female. A mature ovariole contains eggs from eight to thirty-four. The maximum of total eggs within ovarioles in a female could reaches 680 and on an average 270.5 in 16 dissected individual females.

The Self-thinning equation of even aged pure stands, that was proposed by one of the authors, was tested. The equation is Testing result showed that the processes of self-thinning was properly described by the equation where δ, in the equations, was determined by a initial state of a stand. β denoted Reineke's self-thinning coefficient. S_f was the maxmum density index, γ was self-thinning power. F-test was emploied. The results show that maxmum density index of stand was close to a constant for a certain species but independent from site, region where stand located, stand age and initial state of the stand. The value of δ was also independent from site, region, age and initial states, but a bigger sampling error could exist.

The patterns of spatial distribution of soil erosion and its relations with environmental factors in a range of topographical types in the upper reaches of the Yangtze River were studied through general survey and the establish- ment of permanent and temporary plots. The mechanism of silt transfer and principles of soil erosion were described and the ratios of silt transfer of watersheds were determined, 0.6-0.7 for the watersheds with an area smaller than 5 km² and 0.3 for those smaller than 30 km². Quantitative models to predict soil erosion in the slopes and watersheds were also established.

This paper studies the inheritances and correlations of wood quality characteristics among Populus ×'popularis' improved clones. The significant differences among clones were found in fiber length, fiber widness, ratio of length to widness, (double) wall thickness, wood specific gravity, widness of annual ring, tree height, DBH and volume.1. Higher reapitabilities, larger genetic coefficients of variation and genetic gains were found in fiber length, ratio of length to widness and wood specific gravity.2. No significant correlations were found between wood specific gravity and growth traits, wood specific gravity and fiber traits according to three methods of simple correlation, path analysis and canonical correlation analysis.3. Fiber length, tree height and DBH have larger direct effect to volume. Fiber widness and ratio of fiber length to widness have negativ direct effect to volume. 4. Two group traits of fiber traits and growth traits were significant correlation due to the correlations of fiber widness with volume; ratio of length to widness with tree height; fiber wall thickness with widness of annual ring.

With the help of methods of thin-section and histochemistry dynamic changes of resin droplets and starch grains in resin duct cells at different developmental stages of resin duct are observed and studied.At the initial stage, few resin dropletS and 2-5 starch grains occur in the cytoplasm, at formative stage, the number of resin droplets gradually increasee.their volumeenlarges, starch grains changes with a same trend, both of them all are evenly distributed in the cytoplasm.At the mature stage, the number of resin dro plets obviously decreases, most of them occur in the cytoplasm near lumen, no great change take places in the number of starch grains, but their volume apparently contracts, usually they are present in the cytoplasm far away from lumps. During the development of resin duct, no, obvious change appears in the number and volume of resin droplets and starch grains in sheath cells.

The authors took Korean pine (Pinus koraiensis Sieb.) as sample wood and studied the change of free-radical concentration of the sample wood surface by means of these factors: electromagnetic radiation, water, heat, oxygen and ozone. The results showed that among above factors, the most important one which degraded the lignin and produced the free-radicals mainly is ultraviolet radiation (UV).

The resources of poplar tree in China were introduced briefly, and the achievements in poplar tree hybridization breeding of China were reviewed.The process of hybridization breeding in this tree species is divided into twoperiods.The problem of breed variety for poplar cultivation in north parts of China was solved during the first period.The current situation of planting poplar trees with the exotic clones directly in the regions from the south of the Yellow River to the middle and lower reaches of the Yangtze River was changed during the second period. However, there still exist the dangers of the potential breeding in the spreading of the clones with the close relatives because of the two period of breeding activities within a same generation, and lack of the procedure and method to be improved in hybridization breeding during euch a short period, always taking the species hybrid F₁ as the key of selecting clones, and the limitations of gene resources.The development of poplar breeding was stagnated as the plan was short of a combination of the long medium, and short period and the study on gene resources was not enough.Therefore, it was suggested that laying down the longterm plan based on the natural conditions of a region and the demand for species, strengthening the introduction of poplar tree resources from abroad, and tranfering breeding focal point from individual rapid growing to multiple characters and all directions will be the heart of the Chinese poplar breeding in the future.

The results showed that the critical points of light compensation and saturation in Ginkgo seedlings were about 78μmol m^-2S^-1 and 1050μmol m^-2S^-1 respectively,which meant that Ginkgo was a light-demanding Plant.CO₂ compensation point was 100μl 1^-1.It was found that the suitable leaf tem perature for photosynthesis was about 26℃.Under normal cultivation conditions the diurnal change of photosynthetic rate showed a double peak curve and a obvious midday depression.Stomatal limitatiion was main factor causing midday depression of photosynthesis, but sometimes nonstomatal limitation was noted.Ecological factors causing stomatal limitation were mainly low air relative humidity and high vapor pressure difference between the leaves and air.However,high leaf temperature was main factor other than stomatal limitation.The measures to alleviate or to decrease the midday depression of photosynthesis were also discussed

To determine the seasonal changes in the growth and nutrient contents of the female cone for Pinus massoniana Lamb., the growth of the female cone in length and diameter and the nutrient compositions were determined monthly in a 25-30-year-old stand during two successive years at Anhua county, Hunan Province.The results showed that the duration from pollenation to cone mature was about 540 days.The volume and weight of the conelets increased a little during the first year, which were in a bilinear curve model.The growth in dimension and weight of the cones increasded rapidly after April of the second year, which showed a logistic curve model.The seasonal changes in the concentrations of N, P, and K in conelets showed a "V" manner.The concentrations of micronutrients, such as Fe, Zn, and Mn increased gradually from pollenation period to the first winter, while the Cu content remained at a lower level. In the second year of the cone development, all of the contents of mineral elements in cones decreased gradually with the increasing of cone weights.The concentrations of macronutrients in cones from high to low were K>N>P>Ca>Mg and Mn>Fe>Zn>Cu for micromutrients.

The injury process of the chestnut gall wasp, Dryocosmus kuriphilus Ya sumatso, an important insect pest of chestnut, and its control were investigated. It was found that killing of the first-instar larvae in the buds just before winter resulted in normal growth of the buds the following year and that once a year of high-dose spray of monocrotophos between the time of harvesting and leaf falling killed 75%-95% of the larvae and effectively reduced the injury.This method was safe to the natural enemies and the re sidue of insecticide was near zero.

Tettigoniella viridis (Lennaeus) damages trees principally by ovipositing activities.When saplings or young trees of Populus alba var. pyramidalis (Bunge) are infested, the thinner bark becomes rough, and its colour turns yellow, growth of the saplings slows down, leaves fall earlier while sprouting delays, What is more that the scars caused during oviposition on the bark multiply saplings' water losses, greatly decrease water content of the stems and branches, and make tops of the young trees wither easily, Number of the oviposition scars on the stems of one-year saplings of Populus alba var.Pyramidalis (Bunge) distinctively correlates to the ratio of water decrement.The regressive equation is y=8.5001+0.1809x. Its coefficient of interrelation is 0.9482, which is extremely significant.The younger saplings are, the more serious damage is. It is worked out through three years' experiment that ec onomic injury level(EIL) of Tettigoniella viridis(Lennaeus) to one-year poplar trees is 19.54 egg lumps/0 -50cm, to two-year trees is 24.98 egg lumps/0 -50cm. Control index of adult pests for the former is 10.7 heads per sapling, for the latter is 13.7 heads per sapling. Tettigoniella viridis(Lennaeus) is less harmful to trees older than three years since they possess more branches and their stem bark becomes lignified.

By use of techniques of telecommunication, computer, ann forest insect pest forecast, the compter technology of speciefic code, model forecast telegraph and decode information of forest insect pest forecast were developed, which were suitable to telecommunication or computer net fast transmission.'These developments could speed up the transmission of information forest insect pest forecast and realize the automation and standarization of the informa-tion of forecast in China.Their fast, accurate, simple and economic characteristics provided the theoretical and applied basis for the computer netsystem and opened up a new area for the use of computer in forest insect pest forecast in China.