The Larch thinning juvenile wood (Larix gmelini (Rupr.) Kuz.) is indicated rapid wood increment, light colour (heartwood has not yet formed), lower percentage of latewood and even-textured (smaller differences between the structure of early- and late wood, transition from early- to late wood gradual to more or less abrupt). The fibre morphological characteristics include : short length of tracheids, thinner cell wall, lower Runkel ratio (2w/l) and lower coefficient of flexibility (l/D). In a word, these characteristics and the ratio of fibre length to cell wall thickness (L/D) are better than those from branchwood and stemwood, especially in latewood tracheids. The Larch thinning juvenile wood (and topwoods) is supposed to be a suitable raw material for pulping and papermaking. The pulp yield from the Larch thinning juvenile wood is higher than that from branchwood and is similar to that from stemwood. The strength of paper made from both barked and unbarked thinning juvenile wood also meets. The National Technical Standard of Kraft Bag Paper and is better than that made from branchwood of the same species. Newspaper may be made from the above raw material by means of logor chip-groundwood pulping processes. Prosperous growing and development of Larch in its juvenile stage explained itself as a favourable species for short-rotation intensively cultured (SRIC) system in the northern provinces of China. For the purpose of promoting a rapid growing increment during the juvenile period (first decade) of Larch and greatly increasing the yields of fibres per unit area, the author suggests that those authorities concerned must do some further experiments on this SRIC system and make some plantations for pulp and paper industry.

Mu-sheng (Homalium hainanense Gagnep) is one of the rare tropical broad-leaf tree species found in Hainan Island. It is fast growing and gives fine quality timber. Growth rate of plantations began to decrease in 2 or 3 years after the stands closed. Foliar analysis was used to find out the status of mineral nutrition of the stand, which appeared to be the cause of slowling down in growth. Soil samples from the same plots were also analyzed. As results of both these analyses were compared, changes in N or P content of the leaf showed a close relation with that of the soil. In the beginning, young plantations, either in the humid or in the arid part of theIsland, sohwed fast growth both in height and diameter on soils of high N and P content. As they were getting older, growth rate fell down, because N or P was depleted in the soil, mean while a decrease of N or P content in the leaf was also observed. Foliar analysis is, therefore, considered as a very satisfactory diagnostic method to ascertain the mineral nutrition status of the young Mu-sheng stand. Based on such findings, silvicultural treatment, such as application of fertilizers,was suggested to improve growth of the stand.

The accuracy of site index curves has been estimated by using the 24-term time series h₍₃₀₎(i, t_j)=β₁(t_j)h₍₃₀₎(i, t_(j-1))+β₂(t_j)h₍₃₀₎(i, t_(j-2)+β₃(t_j)h(30)(i, t_(j-3))+ε(i, t_j)which is simulated by tetrachoric model in 4 site types of larch (Larix olgensis Henry)plantation. The test result showed that the degree of accuracy of site index curve fitted by data of temporary plots is the highest and the mean square error varies within 0.2-7.3dm.

This is a report on the experimental results of anther culture for genus Populus. Pollens of 14 spp (Populus simonii×P. nigra var. italica + Salix matsudana, P.simonii ×P. nigra, P. nigra var. italica, P. euphratica, P. pekineca, P. euramericana ev.‘Polska-15A' etc.) and nine were ased. Callus of anther was induced by BN or nitsel medium in which kinetin or auxin of know concentrotion was added. Differentiation was saccessful on modified MS medium (by adding BA, IAA or NAA of different concentration) and 900 plantlets were roised and tramplanted in seed bed or pots. Some of them reached a height of 3.9 m in three years. Chromosome counting of root tip cells showed that most of them are haploids. It was certain that the plantlets were of pollen origin.

The new species Camellia Weiningensis Y. K. Li as described in this paper is closely related to C. breristyla (Hay.) Coh. Stuart, but distinquished by its glabrous and persistent perules, red, white, or pink and glabrous corolla, the 3-5 celled ovary and the 3-5 longer connate styles. This very interesting species was discovered at the altitude of 1,800-2,700 meters is Weining county in western part of Guizhou province. Some of it fine qualities are insusceptibility of diseases and endurance of cold weather and poor, dry soil. Oil content of the seed keruel is 43-54% by dry weight, but commercial yield is only 24-30% when the native press was used, but higher. The oil is of good quality and as delicious as that from C. oleifera Abel.

Needle blight caused by Pestalotia funerea Desm. on Pinus massoniana is of common occurrence in pine plantations in Szechuan. Conidiospores may germinate easily at various temperatures ranging from 5℃ to 33℃, with an optimun at 24-25℃. Conidiospores are transmitted by rain and wind. Symptoms appear on current needles from May till October every year. Peak of infection was observed in the middle to the end of July. Heavy rains in May and June followed by high tamperature of low humidity in July are the main factors to bring about an outbrust of this disease.

A study on the Zeuzera coffeae Nietner was made in Jiangsu province from 1977 to 1978. There is one generation a year. The larvae are borers which infest the twig of trees, including locust, hickory, apple and other, and overwinter in the tunnel of deied twigs. The adult emerges from middle May to early July the next year and lay its eggs in the tunnel of dried twigs. New hatched larvae are thrown about by wind and bore holes at the edge of buds. Infested shoots wither quickly and will readily be broken by wind. The male moth is active at night and may be attracted by light. Natural enemies of the larvae amount to more than five species, namely, Bracon sp., ant, Fusarium moniliformes, virus and birds. Several insecticides, such as Omethoate, Sumithion, Imidan etc. were used to spray or brush on the trunk to control the larvae, but results showed that these insecticides had little or no effect. Silvicultural measures, including cutting off and clearing away the injured twigs should be recommended for the control of this pest. Natural enemies should also beprotected and utilized.

Samples of turpentine and rosin from six species of pine Grown in different regions of China, have been Collected and analysed by gas chromatography. Turpentine from Pinus massoniana consists mainly of α-pinene and β-pinene, which representing over 90% of the total. This is also the case of turpentine from Pinus yunnanesis. The turpentine from Pinus elliottii contains β-pinene as high as 39.4%. The α-pinene contained in turpentines from both Pinus langbianensis and Pinus finlaysonlana is dextrorotatory. Pinus langbianensis turpentine has the highest α-pinene content amongst the samples tested while turpentine from Pinus armand contains more β-pinene (15.1%). Rosin from Pinus massoniana contains 76-86% resin acids of abietic type. There seems no distinct relationship between chemical constitution of rosin and the locality of tree growth, but on the other hand, some characteristic features in the composition of rosin of different origin do exist. for instance, Pinus elliottii rosin contains more than 20% iso-pimaric acid and about 9% dehydroabietic acid. rosin from Pinus finlaysonlana contains 18.5% dibasic acids with higher iso-pimaric acid content and no pimaric acid. The content of abietic type resin acids in this rosin is the lowest (53.2%) in compare with the others. The composition of resin acids in rosins from both Pinus langbianensis and Pinus yunnanesis is similar to that in Pinus massoniana, Pinus armandi rosin contains resinacids of abietic type as high as 90% but with no dehydroabietic acid presenting. The rather evident differences in chemical composition of turpentine and resin acid constitution of rosin between samples from different specice of pine might give us some genetic informations of the trees.