Chinese torreya (Torreya grandis Fort. cv.'Merrillii') is an endemiceconomic tree species in our country, which is dioecious. The chromosomalanalyses of the cells in root tip, show that the female plant has a pair ofheteromorphic sex chromosomes, which are heterogametic sex and belong toZW type. The male plant is homogametic sex and belong to ZZ type. Thekaryotype of the female plant is 2n=2x=22=22m (2SAT+ZW), while thatof the male plant 2n=2x=22=22m(2SAT+ZZ) In the somatic cell of the female plant there is only one shortestz chromosome, and the difference of the sizes between the two chromocentres of interphase nuclei is notable. The male plant has a pair of shortest Z chromosomesand the sizes of the chromocentres of interphase nuclei are the same. According to these characters the sexuality of the plant can be discriminated atearly stage,

The main site factors which enfluence the evaluations of site quality,including flow degree, position and size of sandhill, and nonsite factorsincluding age, density and cuting, are selected out by taking biomass (aboveground) as the index of evaluating site quality of shrub forest. The quantitative mathematic model is establishedd by converting qualitative data to quantitative data as the independent variable, and biomass to be the dependentvariable, by which quantitative tables for 9 shrub species, such as Caraganaintermedia, C.korshinskii, Hedysarum scoparium, H. lacve, Salix psammophila, Amorpha fruticosa, Hippophae rhamnoides, Artemisia sphaerocephala, A.ordosica, are drawn up. The correlation coefficient, surplus standard error, aswell as other indexes are adequate to demands. On the bases of the tables,the biomass of various shrub growing in the same type of site can be evaluatedcomprehensively so that the shrub species can be matched with the sites. Thecrown breadth and height of shrub reflect the boimass yield above ground,the multiple regression mathematic model can be established, which providesa simple method for evaluating the shrub biomass in the forest land.

The commercial inoculum of Suillus grevillei which was produced with aliquid fermentor was inoculated onto the container-grown Chinese pine see-dlings, together with the spore slurry of Pisolithus tinctorius, bacteria inocu-lum and phosphate fertilizer in the different type of combinations. Havinggrown for only 100 days, the mycorrhizal seedlings were used for afforestationin Chinese Loess Plateau. The results of this 4-year-experiment showed thatthe optimum treatment was the combination of S. grevillei, bacteria andphosphate fertilizer, the treatment which was the combination of mycorrhizalfungi and fertilizer performed better than the one which used only mycorrhi-zal fungi, the treatment which used only fertilizer performed better thancontrol but was not as good as other treatments. It could be concluded thatmycorrhizal fungi could enhance the growth of seedlings, especially in dryweight and phosphate absorption, increase the survival rate of afforestation,continue to exert their abilities to accelerate the growth of seedlings in theafforestation sites after 3 years.

The photosynthesis rate, transpiration rate, chlorophyll content and treegrowth are all found to be decreased remarkably by 2-3 years' repeated over-pruning (only two branch whorl reserved) or over-pruning plus defoliation in Pinus tabulaeformis stand which has been closed to human activities for eightyears. As a result, the decreased content of soluble carbohydrate and starch,and the increased contents of fat and protein make the total quantity of heatin needles as insect food increased. This benifits the weight growth rate of Dendrotimus larvae, and weakens tree resistance to insect. Therefore not onlythe photosynthesis rate and tree vigour, but also its resistance to insect couldbe increased through reasonabl pruning. Experiments show that most current needles of Pinus tabulaeformis are onthe fourth branch whorl, and they are extremely important to accumulatingphotosynthetic products. Based on the experiment result, the standard of reasonable pruning of Pinus tabulaeformis is discussed.

DENTROL(DENsity conTROL model) is a computer model for the opti-mization of stem densities of Chinese fir plantations, which is based on theNational Experiments of Planting Density, and Tending and Thinning ofChinese Fir Plantations, and referencing to the New National ManagementTable of Chinese Fir Plantation, and formed according to distribution zone,distribution area and site indexes. The concept of the optimization of densitycontrol is the selection of a series of elements concerning stem density of astand, including initial planting density, year of first thinning, thinning intensity, times of thinning, ages of harvesting, and planting aim, from whichthe final internal return rate (IRR) will be maximum or so. Data from 12plots in Tending and Thinning Experiment were used to test the accuracy ofthe model in predicting stem growth. The results showed that the standarddeviation was +/8.9%, the systemic error was 1.8%, which are enoughfor the demand of forestry production practice. According to calculations,based on the plantation of the whole country, the average net present valueper hectare of plantation managed with optimized stem density will increase(?)321. 7, bu 17.0% , and which will increase (?)892. 4, by 47.3% , if only basedon the main commercial timber base——the distribution area of Chinese firplantation.

620 Chinese hardwood species were investigated into their xylem crystalliferous cells by means of SEM and light microscopy. 231 wood species from114 genera and 44 families were found containing crystalliferous cells in theirxylem paranchyma cells, 7 types of crystals were classified and described inthe present paper. They were prismatic, acicular, raphide, styloid or elongate, crystal sand, small cubic and druse, of which types, size and locationwere proved to be of diagnostic value. The occurrence of crystalliferous cellsin xylem is common to many Chinese hardwood species, specially tropic species.

Studies on wood properties and characteristics of Cunninghamia lanceolataof twelve provenances from four provenance trials were taken, and show that the variations of wood properties and characteristics and anatomy of fibersfrom these provenances, are notable, that of chemical components are muchlittle. According to requirment of constructal wood properties, such as airdried density, maxium compressive strength parallel to the grain, maxiumbending strength and modulus of elasticity bending strength et al., obviouslythese provenances are distinguished as better (in Northern and Southern ofsubtropics) and slightly poorer(in central of subtropics). The chimate factorsare main effective factors to affect the variations of wood properties andcharacteristics. By means of comprehensive assessment, results are illustratedas following: provenances in Jingping, Guijhou province; Jian'ou, Fujianprovince and Rongshui, Guangxi province are more suitable seed resourcesfor plantations of constructal wood; those in Pubei, Guangxi province, Xingyi,Guangdong province, and Hanzhong, Shaanxi province, Huoshan, Anhuiprovince are suitable for utilization of hybridization of seed resources or sele-ction of clonal seeds.

In this paper, by analysing some forestry-climate indexes, the 9 speciesof Paulownia in China are divided into 2 climato-ecological types, the lowwarm index-middle rain coefficient type and the high warm index-high raincoefficient type. Even though the cold resistance are distinct among differentspecies of Paulownia, they require more water in growth period. Based on theanalysis of the phenological records from 28 locations in Cast China, a phe-nology-geographic model of Paulownia is set up, which shows that the dateof each phenophase varies regularly with the latitude, longitude, and altitude.The first date of flowering period in any place is related to the temperatureof certain period before the flowering.

The distributions of female and male cone, as well as seed cone in thecrown of Chinese fir (Cunningbania lanceolata Lamb. Hook,) trees either fromseed orchard or normal forest land are investigated by growth age section inShangganshan forest farm, Shanggao county, Jiangxi province. Based on this,the information section of flowering and fruiting forecasting the corn cropof a tree is developed by progressive regression. The results indicate that theway of forecasting the cone crop of a individual tree has a higher accuracyand can be used widely.

The air seeding effects in Pinus tabulaeformis Carr. Have been studied bythe way of variance analysis and quantitative gradual regression. The resultsshow that among many factors elevation, slope site, thickness of soil layerand slope gradient have combined influence on air-seeding effects. The mu-ltiple linear equation has been formulated by the relations between these fourcritical factors and aerial seeding effects, and the more satisfactory resultshave been obtained in the use of predicting air seeding effects. Therefore,this study will be very useful for choosing site conditions and evaluating sitequality of seeding area, and increasing aerial seeding effect, and also hascertain significance for predicting effect of aerial seeding at early stage.

On the basis of investigation of sample plots, statistical analysis demonstrate the relationship between site factors and natural Larix gemlini growth.The dominant factors are found by three multiple statistical analysis (quantizedmodel-1, general variance analysis and principal component analysis). Theorder according to their importance is: copographical position, soil layer depth, slope aspect, slope gradient and soil moisture. Site type groups and sitetypes are divided according to the dominant factors. This investigation mayprovide the bases for predicting forest land productive forces and working outreasonable afforestation plan.

In Kunming district, Yunnan pine is the only host tree of Tomicus piniperda (L. ). The pine shoot beetle usually reproduces in living tree, but haveno eminent taxis to the logs and stumps of the host trees. The testing of theviolent compounds in the postgut of the beetles by MC/GS/DS showed that,there were verbenone, transverbenol and myrtenol in it. The amounts of verbenone was low before reproduction in the tunnel, and increased with progress of tunnel constuctrion. The amounts of transverbenol and myrtenol werehigh in the early of the reproduction, and then decreased with time. On thebasis of comparing with mass attack behavior of the pine shoot beetle, it issuggested that verbenone has a inhabitant influence on the pine shoot beetles'aggregation, transverbenol and myrtenol could have active effect to the beetleaggregation.

Using the propertional value of temperature standard deviation δ_x to average temperature , the rearing date of Masson pine caterpillar, Dendrolimus punctatus Walker was analyzed. The results showed temperature coefficient isan important index influencing the development of caterpillar. Within favorable temperature range, at the same developmental stage, the average temperature among the Masson pine caterpillars were close to each other, but thetemperature coefficient differesgreatly from each other. While the temperaturechanges strongly, the larvae develop slowy; while the temperature changesweakly, the larvae develop quickly. There is no significant correlation betweenthe number of generation and the annual average temperature and the decadeaverage temperature higher than 10℃; but there is very sinificant negativecorrlation between the number of generation and the coefficient of decadeaverage temperature higher than 10℃.

According to the information of 337 sample plots of 20-25-year-old Chinese pine plantation at sapling stage, the diameters at breast height offorest trees which are at the standard of 4m or 2m rafter timber, have beendetermined in this paper. The regression equations of density and numbers ofsapling timber have also been established based on the site types, and thenumbers of 4m and 2m sapling timbers in different density stands have beenanalysed. The number of 4m sapling timber per unit area is positively correlated with the volume and economic value of sapling timber. The stand density and planting density have been proposed for the goal of sapling timberin Chinese pine plantation.

The main reason for the melting-settlement of highway bed in the permafrost area in Daxing'an Mountain is artificial swamp transformation whichdeteriorating the surface run-off condition and raising heat exchange betweenthe surface water and the permafrost. Method with best economic benefit ofblocking the base bottom of the culverts with sacked clay and applying themalinsulation technique with foamed plastics i. e is suggested to deal with the melting-settlement of highway bed. It is also pointed out that assessment ofenviroment effect of large scale planting or construction is necessary.

The paper discussed kinematical characteristic of clamping tree mechanismon supporting arm seed collecting ladder and the mathematics models of thebest optimum design were founded for satifying its structure, function andtechnology, and computer program of SUMT+Powell successfuly were run inPC-1500 pocketcomputer. We have optimum designed its series of IZT-SJ.The design not only saved time but also markedly raised technology and precision on it.