This paper briefly described the problems on the lock gate of logway both in theory and experiment. The principle of the gate which can be opened and closed automatically without any machine is making bearing hinge to generate unbalanced moment by use of combination of its weight, water pressure, buoyance and friction. It is convenient in operation and simple in structure. This new type of gate can be used in the inlet of logway and may be of some practical value in wood transport engineering by water.

The timber of Yunnan pine (Pinus yunnanensis Franch.) grown in the south-eastern, north-western and the central region of Yunnan province are used for the study on physico-mechanical properties.According to the test results, the shrinkage coefficient, specific gravity, and compressive strength // to grain of the air-dried timber of Yunnan pine grown in the north-western part of Yunnan are the smallest, next in southeast, and the largest in central region. While the bending strength and modulus of elasticity of timber grown in south-east are the largest, next in north-west, and the smallest in central region. Owing to the timber of Yunnan pine, grown in the north-wetern region of Yunnan, are straight in grain, softer, easy processing and the smallest shrinkage coefficient, therefore the timber quality is the best. The quality of timber grown in central region is the lowest.The differences of physico-mechanical properties of the timber of Yunnan pine between various heights or heartwood and sapwood are very small. The differences of physico-mechanical properties between each tree are in 1—5%, most of which are about 2%.

Three species of sawflies new to science are described in the present paper. Typespecimens are deposited in the insect collection of the Forest Research Institute, the Chinese Academy of Forestry, Beijing, China.1. Nesodiprion yananieus Huang et Zhou sp. nov.This species resembles N.japonieus(Marlatt),but differs from the latter in having the ventral lobes of the 2nd and 3rd annuli smaller, the 3rd annulus being parallel to the 4th, the pseudocepal thickening slightly depressed, the valviceps almost forming a right angle.Holotype: ♀, Shanxi province.Allotype: ♂, the same as for the holotype.Paratype: 2♀, 1♂, the same as for the holotype.2. Nesodiprion zhejiangensis Zhou et Xiao sp. nov.This species differs from N. japonicus (Marlatt) in having the pseudocepal thickening slightly depsessed, the valviceps forming and the 2nd sclerora each forming a right angle.Holotype: ♀, Hangzhou, Zhejiang Province.Allotype: ♂, the same as for the holotype.Paratype: 15♀, 50♂, the same as for the holotype.3. Nesodiprion huanglongshanious Xiao et Huang sp. nov.Nearest to N. japonicus (Marlatt), but distinguished at the ventral lobe of the 2nd annulus large and almost in quardrate shape, the pseudocepal thickening being rather flat, the valviceps forming a right angle.Holotype: ♀, Huanglongshan, Shanxi Province.Allotype: ♂, the same as for the holotype.Paratype: 11♀, 10♂, the same for the holotype.

The pathogen of anthracnose(Colletotrichum, sp.) on China fir has a strong saprophytic ability. Residue of tissues affected can provide the source of pathogen for a long time. The pathogen can directly invade host plants, besides wounds. From late spring to early summer when shoots of China fir are growing quickly, the infections reached to a greatest amount. In seriously affected stands, new shoots are approximately entirely attacked. Part of them appear symptoms in autumn, but most of the affected shoots are diseased in the next spring. The incubation period is more than ten months. Weak trees are more easily attacked while strong trees do not appear symptoms although the pathogens are in the tissue. Thus, the basical measures to control anthracnose on China fir are finding suitable place for planting and good care of growth. A determination of the duration of infection provides scientific basis for fungicidal application.

The geographic distribution of Pinus tabulaeformis is discribed on the basis of exploration in 1978-1979 and the provenance regions is classified by means of principal component analysis.The horizontal distribution of this Pine covers a wide range with quite different climatic conditions and is characteristic of discontinuity due to arid and human disturbances. It extends over several vegetation zones (desert, steppe, deciduous broad leaved-forest and north subtropical forest). The vertical distribution in east is 100-1500m, in Yanshan region and rises to 2000-2700m. in west in Qinghai province,but from south to north the upper limits vary little in general, even though lower limits evidently rise through the same direction. The correlation coefficient of upper limits with latitude is -0.43, but not significant, with longitude is -0.71^**, significant; The correlation coefficient of lower limits with latitude is 0.55^**, with longitude -0.84^**, both significant.In the principal component analysis, derived from the correlation matrix computed on eight climatic and geographic variables (annual mean temperature, January mean temperature, July mean temperature, thermo-index, annual precipitation, aridity in spring, latitude, longitude), the eigenvalues and eigenvectors are computed. Because λ_{1 and λ², account for 86.8% of total variance, using first and second principal component scors, the two dimension's ordination diagram is constructed, denoting the similarity in climate conditions of some forest region. According to this, the entire range of Pinus tabulaeformis is divided into ten provenance regions.}

This paper illustrates that the Eastern part of Sichuan province and the Western part Hubei Province are concentrated areas of the majority of Paulownia species in accordance with the data of the palacobotany and the distribution conditions. These areas may be the asylum for Paulownia genus after the fourth glacial epoch. These areas as well as the middle and lower reaches of the Yangtze River are the distribution centre of Paulownia. This paper also discusion that Paulownia belongs to the East Asian flora of the palacotropical origin according to its morphological and ecological characteristics. It shows that Paulownia is of tropical and sub-tropical species. Consequently, the potentialities for developing Paulownia in the broad Southern regions in China are greater than the cultivated centre of Paulownia in the plains of the Yellow and Huai Rivers.

In order to study the role of hormones in the morphogenesis of witches' broom, tissues near the base of axiltary buds from the healthy and diseased young trees of Paulewnia elongata S. Y. Hu and P. catalpifolia Gong Tong. Were collected and cultured in vitro in MS medium with benzyladenine (BA) and indo-3-acetic acid (IAA) at different levels. When the tissues of healthy plants were treated with relatively high concentration of BA (1.5—3.0mg/l) and low concentration of IAA (0.1mg/l) in MS medium, the proliferation of lateral shoots was promoted,while the rate of IAA become higher(1.5—2.0mg /l) and that of BA lower (0.1mg/l) for diseased plants, such growth was inhibited.Besides, the endogenous cytokinins and IAA in the healthy and diseased plants were extracted and isolated. Ethanolic extracts passed through ionexchange resin, and further purified and isolated by thin layer chromatography. Cytokinin was identified by means of Amaranthus bioassay and ultraviolet spectral analysis. The extracted cytokinins were basically indentical with that of standard zeatin and isopentenyladenine. The absorption peak was in the region from 270—280nm, and the biological activity of the extracts from the diseased plants was shown higher than that from the healthy.The preliminary results in bioassay by the wheat coleoptile straight-growth test showed that the activity of IAA extracted from diseased plant was weaker than that from the healthy plants. Electrophorsis analysis for the isoenzymes of peroxidase in the extracts from both healthy and diseased plants were compared.From these results, it is suggested that the morphogenesis of witches' broom is controlled by the interaction among the hormonal levels. Cytokinins play an important role in the promotion of the proliferation of axillary bud growth; but auxins inhibit it.

Treatment of young leaves with 800 to 1200 ppm. of ethrel the produced clustered secondary shoots on nearly all the nodes. After the removal of the primary leaves, the clustered secondary shoots were hurried in soil while still connected with the mother plant. Four months later, about 50% of the clustered secondary shoots bore roots. They could survive when separated from the mother plant. When the secondary shoots were further sprayed twice with 1,000 ppm. ethrel, the rooting percentage increased to 90%, with well developed root system. Ten months after planting, the secondary shoots tillered 2—5 times. The bamboo shoots thus obtained reached a height of 50cm, some even 100cm.This new method of propagation has many advantages: It does not need seeds; it is very simple to manipulate, the percentage of survival is high.

This article is developed to describe the whole process of "∫" growth of woody plants——Power-exponential equation of growth:S=ce-^Bt-A This equation is different from the general model of the simulating growth, it is infered from the theory of growth described below: with rest conditions equal the absolute growth rate (dW/dt) of the weight of the plant body is directly proportional to the weight of the original plant body (Ⅳ), and inversely proportional to the decrepitness (t^α). Hence mathematic expressions of the absolute growth rate, the relative growth rate and the fastest growing time are derived therefrom.It has been proved that this model is of a higher goodness of fit, the index of correlation ordinarily can reach above 0.99, by using that equation to fit pratical data, and compare with some models of growth. It can be used for gorwth projection and construction of yield table. Theoretically, it may be valuable to interpolation of missing data, and searcting the way of plants growing mechanism etc.

The method to work out yield table described in this paper in the light of stand density diagram and site index curves. The author illustrated the process of working out the yield table by an example of man-made Larch forest in Ji-lin province.

A formula for the calculation of the mid-diameter has been investigated. The advantages of this method are as follows:1. Less troublesome in measurements of diameters of upper part.2. Avoiding much error in measurement with instruments.3. Easy to make use of electronic computation.The data detection of some calculations are included.

During the year 1974—1978, a study on the growth condition and the regulation of seed bearing of scotch pine have been carried in Honghaergi Hulunbaier district.It can be accelerated the growth of breast-height diameter in full light whereas the height growth is somewhat inhibited.Although scotch pine is a indigenous species in frigid temperature zones, the annual average temperature is less than -5℃ or less than 15℃ in June, that these factors are not favourable for the height growth.The precipitation in June is the major factor to affect the height growth of scotch pine, but it does'nt affect too much.When the rain and heat are synchronism, the growth in height is the fastest.Scotch pine begins its seed-bearing at 10 year old, and heavy crops at 30. The seed production is increased with the age, and the quality will be decreased over 80 years old. It is concerned with its breast diameter, height growth and the width of crown.When the stand canopy density is 0.5, the seed production in the unit area is the heightest.

This paper deals with the morphological characters of adult, nymph and egg, the bionomics and control measures of the scale insect Insulaspis pini (Mask.). Observations and experiments were carried out in 1978—1979 The scale insect injures mainly on pine, fir and podocarpus and lives at the leave base. It has two generations a year and overwinters as female adult. Integrated control is proposed to against this pest.