On the basis of eighteen needle,cone and seed-trails,56 natural stands of Pinus tabulaeformis in different parts of the entire range are shown to illustrate the geographic variation.The differences of 18 traits among stands are all highly significant and the geographic variation of some traits has close relationship with climatic conditions.There was a trend to have shorter and wider needles,bigger cones and seeds in cold and dry climate,but some exceptions occur in west parts of the range.The geographic variation of studied stands exists in two directions,namely latitude variation under the same longitude and variation from south-western part to north-eastern part across the entire range.

1. From a comparison of the growth rate of Chinese Cryptomeria fortunei Hooibrenk ex Otto et Dietr.and that of Japanese sugi(C.japonica(L.f.) D.Don),including both seedlings and mature trees grown in different geographical localities,it has been shown that the former is better adapted to the warm and humid southern region,while the latter is hardier in the cold winter of the northern region.By such comparison,it is evident,each species has its own genetic merits which might be taken as an indication of rich germaplasm source for improvement of these trees. 2. Test of Chinese sugi seeds from 21 geographical localities showed marked differences in seed weight and germination percentage.They are colsely correlated,with γ= 0.6234. 3. In provenance test of these seeds at 4 stations,the first year seedlings showed statisically significant differences in growth rate.The best one is about twice that of the poorest one.The percentages of increase in growth from seeds of different provenances as compared with those collected at the 4 local stations,are 18—72%.

In order to study laws of soil and water loss of tropical rainforest and the exploitation and utilization of its land.We have carried out the field-plotexperiment of water loss and soil erosion in southern Yunnan for six years from 1962 to 1967. The results of the study are summarized as follows: 1. The seasonal variation of soil and water loss in southern Yunnan is very obvious,it may be divided into three different periods on the basis of soil and water loss during six years. (1) The period of slight soil and "water loss in hot and dry season (Feb.to May). (2) The period of severe soil and water loss in rainy season(Jun.to Aug.). (3) The period of slight soil and water loss in cold and cool season(Sep.to Jan.of next year). 2. The general law is that the runoff,the soil erosion and the runoff coefficient increase with every increase of rain capacity and rainfall intensity in this region. 3. In different exploitation,the soil and water loss of the rubber-tea community is 22.3% and 29.7% 1ower than that of a pure rubber plantation, and 95.7% and 93.9% lower than that of farm crop.Therefore,to transform farm land into rubber-tea community or economic forest land of two stories is a better way to utilize tropical mountainous area rationally and to decrease loss of soil and water. 4. The results of the study still shows that the loss of soil and water on the farm land of shifting cultivation is the most serious.It is 778.3 times and 34.5 times that of tropical rainforest,and 6.6 times and 5.7 times that of bench terrace respectively.In order to restore the function of tropical rainforest ecosystem and to prevent the loss of soil and water on farm land in this region,wé must safeguard tropical rainforest against deforestation.We must change of the slope land to contour terrace,and reform step by step the cropping system of shifting cultivation into that of rational rotation of crops,these are efficient measures to raise soil fertility,keep water and soil, fix farm land and obtain high yield of crops.

For establishing the theory of short wave radiation through the forest canopy,in the forest four canopy cases have been considered: 1) all leaves were horizontal to light; 2) all leaves were perpendicular to light; 3) all leaves were inclined with some angle;and 4) all leaves were distributed at random. The intensity of direct lights absorbed by the forest canopy for all leaves with random distribution may be respectively expressed as following: Where I_b——intensity of direct light absorbed by forest canopy; a——reflection coefficient of the leaf; b——absorbent coefficient of the leaf; F_m——leaf area index; I_o——intensity of direct light on the forest canopy surface;l_o——intensity of direct light under forest canopy;h_o——sun elevation angle.The intensity of diffuse light may be expressed respectively as following:Where ∫I′_bdω——absorbent intensity of diffuse light from concave by forestcanopy; ω——solid angle; θ——zenith angle; I′_b—— absorbent diffuse intensity in some derection of concave; I′_o——diffuse indensity on the surface of forest canopy in some direction of concave. The above formulas agree well with the experimental data and therefore may have certain value in practice.

Chinese fir is an important timber tree in subtropical region of China.The site-index tables are produced in order to predict the productivity and to give reference in choosing proper site of plantation.Data of 1077 stem analysis of dominant trees from different planting areas were collected,18 guiding curves according to log A=a+b 1/A model have been developed individually according to different planting areas.Three height-growth patterns with different shape of curve are divided on the basis standard deviation of b value of 18 curves.Then,three series of site-index curves are developed from three height growth pattern,and are transformed into 3 site-index tables.These tables are reliable and available for classification and evaluation of forest site within respective range of application

Clostera rufa is widely distributed in Yunnan Province.It is a serious pest of willow and poplar,especially of Salix heromera H=D and Poplus yunannensis Dade.There are two generations a year,winter is passed as lavae in the rolled leaves.In early spring the larvae feed on the bark of the host trees during the shortage of leaves. The bionomics of the pest is given. Experimental results that the insectides Sevin,Phoxim and Pipter were effective and that Sevim had a residual effectiveness of more than ten days.

Separate observations concluded that the primary infections induced principlly either from the flower bud-ends or leaf buds of former year twigs (the biennial twigs),though they did not appear any symptoms. The ability of sporulation and conidial germination were observed.The lesions of the spring shoot were one of the important source of infection to young fruits of camellia. Abundant conidia masses were observed around the base of diseased shoots under high humidity and temperature. The length of latent mycelia in 2-years old twigs were examined.Its distance from the infected spring shoots were no longer than 5cm.So it is necessary to cut with a length of 5cm,beginning from the base of infected shoots in late spring.

This paper shows that warty layers are not easy to be seen,or appear occasionally on the corner of inner surface of tracheids in Subgenus Haploxylon(Softpine)except Section Parry Mayr.but appear commonly on the inner surface of tracheids and the surface of pit border and pit chamber in Subgenus Diploxylon(Hardpine).It is an important characteristic of identification among subgenera,genera,and families in conifers.It is very easy to separate the warty layer from the neighboring layer,the inner layer or the outer layer of secondary wall in the part of pit border,and the inner layer of secondary wall. Warty layers are appeared clearly in the inner surface of tracheid and parts of pit in Pinus bungeana of Subgenus Haploxylon.It is very different from the other species of Haploxylon pines which have their own features.The author has made a systematic study and suggested to establish a new Subgenus Parry based on its gross and anatomical characteristics,ultrastructure,morphology of tree,and some aspects of chemotaxonomy.