The stand density control diagram for Cunninghamia Lanccolata is made in accordance with the theory used in Japan, by combining the practical growing condition of the above-mentioned species in China and collecting 992 stand plots of seedling and 662 plots of stand from cuttings. The diagram is consisted of the full density curve, equivalent height curve, Curve equivalent diameter at breast height, density control curve as well as the natural thinning curve. According to the growing characteristics of the stands of this species, the initial thinning density curve and the minimum reserved density curve after thinning are determined. The diagram may be used for many purposes. It can be used for thinning, forst inventory, prediction of growth as well as the design for sylvicultural practices, etc. The accuracy of the diagram after testing is normally over 90%. It can be generally used for Cunninghamia Lanceolata in China.

The preparation and effectiveness in application of catching materials for heavy metal ions-insoluble crosslinked-starch xanthates and insoluble sawdust-based products were stadied on the basis of the results published by other workers. Precedure of preparation and data of application tests are given.

Two kinds of divisions, equal and unequal, of uni-nucleate pollen of poplar anthers were observed in artificial culture, particularly the former. The nucleus vegetatively derived from both divisions could developed into globular embryos, and formed an irregular callus further.By cytological observation, the callus which emerged from the anthers were originated from the pollen. Its chromosomes are haploid. The chromosome numbers in the root tip of plantlets which derived from the haploid callus are also haploid, such as Populus serotina 272, No, 11, 26, and 45.Callus were induced from poplar anthers which cultured in vitro on medium with MS+2,4-D 0.5-2mg/l+Kinetin 0.2—2mg/l. However, the callus of different species and varieties were in need of various combinations of MS medium composed of 2,4-D and kinetin, when the anthers of Poplus were treated by centrifuge at 2000 rev./min, for 20 minutes and cultivated on MS+2, 4-D 2mg/l+Kinetin 2mg/l medium, the frequency of callus was greatly increased. Adding 50—150mg/l yeast Ribonucleic acid (Y-RNA) to the above medium, the inducing frequency of pollen callus were also efficiently increased. Besides, it appeared that the Y-DNA played an important role in the promotion to initiate the pollen development.While the pollen callus were transfered on MS+BAP 2mg/l+NAA 0.3 mg/l+IAA 0.1mg/l medium, they differentialted into rootless plantlets. The differentiation frequency of shootlets was 90%. Medium with 1/2 MS+IAA 1mg/l was quits suitable for root-system formation in shootlets. Its induction frequency of plantlets was 80—90%.

Diseases caused by Oil Olive rout-knot nematode are very popularly occurred in Guangxi, Guangdong, Jiangxi and Fujian provinces The specimens identified are collected from Guilin and Liuzhou district of Guangxi province. According to its characters, there are four species of Meloidogyne damaged to Oil Olive. They are Meloidogyne javanica (Trenb, 1885) Chitwood, 1887, Meloidogyne incognita (Koforid & White, 1919) Chitwood, 1949, Meloidogyne arenaria (Neal, 1889) Chitwood, 1949 and Meloidogyne acrita (Chitwood, 1949) Esser, Perry and Taylor, 1976. Among these, M. jaranica and M. incognita are the dominant species.

Pseudostachyum polymorphum Munro is a species of economic value in China, but it was incorrectly identified as a new species of Schizastachyum but S. leviculme by an american Scientist F. A. McClure in 1941.Now, according to investigation, the author proved fully that it should be the species of Paeudostachyum-P. palymorphum Munr.The characteristics of morphollogy, distribution and uses of the species are also described.

1. The study of estimate primary production of Picea koraiensis forest communities was set up on the dune of Bai-yan-Ao-Bao district, ke Banner, Zhao-wu-Da League, Inner Mongolian.2. The estimated total biomass of picea koraiensis forest community is 109.31 ton/ha, total deadmass 25.40 ton/ha, net-production 1 ton/ha/year. Total aboreground biomass of spruce is 69.84 ton/ha, in which stem, branch, leab, cone and root is 45.14, 16.87, 7.83, 0.43 and 27.41 ton/ha respectively.The biomass ratio of spruce tree, spruce sapling, undergrowth, and living plant cover is 1:0.057:0.006:0.056.3. The suggestions:(1) Overmature spurce stand must be thinned by high thinning in order to raising biomass and productivity.(2) On acount of the xerophytic character of Picea koriensis, it may be used for afforestion in drought area of northern China as Pinus sylvestris and Pinus tabulaeformis.(3) As the spruce forest on the dune is very rare now, the protection of stand as nature reserve is necessary.

The blister rust on Pinus koraieusis has been identified as Cronartium ribicola J. C. Fischer ex Rabenhorst. Under natural and artificial condition, the telial stage of the pathogen have found on Pedicularis resupinata, P. resupinata var. ramosa, P. spirata, and Ribes mandshuricum in North-eastern China. By artificial inoculation, the pathogon also infected another three Ribes species.

In this paper, the mutual relationship between gap variations and elastic coefficients changes is explained, and the physical nature of these changes is described by analysing the structure defects-gap-of wire ropes. Meanwhile, a corresponding elastic coefficient can be found through measurement of the change rates reflecting both gap existence and change status, thus the measuring precision on the tension of wire ropes can be improved.

The Chinese white wax scale is an important economic and benificial insect in China. The male larva has the function of secreting a kind of white wax which is of great economic value. Though the female larva does not have this function, the female adult may produce the eggs which are the source of male lavas.The insect in question is distributed widely in China, mainly between 23—40 degrees N. latitude and from 50 to over 2,000 meters above sea level, A remarkable capacity of adapting itself to local ecological conditions has been shown by this insect. It may be asserted that there are no differences between the male and female insects in geological distribution and in their requirements for the climate and host plants.In the past the production of the wax and the raising of white wax scale "seeds" were not carried out in one and the same place only because people have different productive purposes. In some places they raised the "seeds" only for sale, while in others they did not raise the "seeds" but purchased them for producing the wax. In recent years this situation has gradually changed. People in many old white wax producing areas have increased the output of white wax by raising the "seeds" on their own. Consequently, good harvests of both wax and "seeds" have been obtained in these areas for several years running.