This study was conducted from 1980 to 1984 in Zhu-Ting forest area, Hunan Province. The study was to find the effects of different ways of site preparation on soil and water conservation and the growth of the young stands of Chinese fir, for the purpose to choose the better way of site preparation based on scientific data.The climate of Zhu-Ting forest area is of subtropical type. The mean annual temperature is 17.5℃, mean annual preciptation 1417.3mm, maximum annual preciptation 1746.8mm. The area is hilly in topography with an altitude of 200—300m and its soil is acidic red soil.The runoff plot-design with four ways of site preparation has been adopted. Each runoff plot is 160m~2 on which 48 seedlings were planted with 2m×1.7m in space. A rainfall gauge were installed in the experimental area to record the amount of rainfall and its intensity. Soil loss and water runoff were measured after each rain. The height and diameter growth of the young stands were measured yearly.Data of 5 years show that the amount of rainfall, rain intensity, topography and ways of tending have significant effect on soil erosion. Capability of water and soil conservation was very different among four ways of site preparation—site preparation of all surface, site preparation by digging trenches, site preparation in strip, site preparation in pit, the mean annual soil losses were 3.144t/ha, 0.454t/ha, 0.06t/ha, 0.023t/ha, the mean annual surface runoff were 9.68mm, 4.68mm, 1.76mm, 0.92mm, respectively. The pit and stripe site preparation give better result of water and soil conservation than the others. The total height growth is as well affected by different ways of site preparation, like wise the mean total height is 2.64m, 2.96m, 1.9m, and 1.05m, respectively. The site preparation by digging trenches and all surface site preparation give the best result on the growth of young stands. The soil losses of all site preparation increases with increasing slop up to a critical point 25°. then a rapid increase happend in soil loss with further increase in slope. According to the close relationship between soil loss and slop, it is very important to apply all surface site preparation carefully.

Man-made forests of uneven-aged and irregular spaced broad leaved tree-Korean pine has been studied for years. The forest is rational at vertical structure. Sun light energy is fully utilized, inside it with the effect of temperature regulation. The forest has a strong water holding capability. The soil of the forest land is loose and fertile, the bulk density of the soil being rather light. Both the aeration and water permeability of the forest soil has been improved, with the helpful result for resolving organism.The average increment in growing stock in the man-made forest of uneven-aged and irrgular spaced was 2.9m²/ha·a during 10 years, increased 3 times as against even-aged pure Korean pine forest, while the increment of biomass was 4.1t/ha.a, 0.7% increased. The sum of investment, however, was only 35.26 Yuan/ha·a, which is 63% less as compared with that for pure Korean pine forest.

Elm spanworm egg parasite, Ooencyrtus ennomophagus Yoshimoto was introduced from the United States in 1981. The number of generations per year is from 7 to 8 in Hang Zhou. Overwintering as a mature larva within the host egg, the egg parasite parasitizes successfuly the eggs of pine lappet caterpillar, Dendrolimus punctatus Walker and the eggs of other 18 forest insect species. The adult stages of O. ennornophagus synchronize with occurrences of the eggs of D. punctatus. It hibernates and aestivates successfuly, and may be established or form populations in Zhejiang. O. ennomophagus is considered to be the potentially effective natural enemy against D. punctatus. In laboratory, eggs of the Dasychira baibarana Matsumura, D. axutha (Collette) and Redoa cygnopsis Collenette can be used as alternate hosts for the rearing of O. ennomophagus.

Accurate estimate of population density in integrated control of the pine caterpillar (Dendrolimus punctatus Walker)is one of the problems that need for urgent solution. In traditional methods the larvae in a tree were counted directly with the naked eye. It is difficult and subject to great errors to use the traditional methods in case of high trees. The relationship between frass-drop as well as related factors and population density ef the pest were investigated in Long-Shan Forestry Farm of Anji County and in Sian Forestry Farm of Chang-xing County, Zhejiang Province.The frass-drops were collected at different stands under different weather conditions. After collecting the frass-drops, the larvae living in the branches above the collector were dislodged by both chemical knockdown and jarring the tranks. Both the frass-drops and the larvae were counted. Many factors regarding time and space were recorded, which probablly affect the relationship between the frass-drop amount and the population density. The data were analysed by simple regression and stepwise regression. A series of mathematical models are developed in this paper.

Through this paper and the pictures, the main results are showed as follows: 1. Membrane of bordered pit in earlywood tracheid is a typical Pinus structural type; 2. Bordered pits in sapwood are deposited by very little amorphous substances so that their fine structure is clear, most of them are aspirated, most tori are dished inward over the aperture; the bordered pit membranes in sapwood that is close to the boundary of heartwood become so thick that dish impressions are decrease. Bordered pits and pit membranes are deposited by the abundent matrix, encrustations and extraetives in the heartwood, so the completely incrusted membranes are formed and the passage between cells may be blocked. These may be the main factor of low permeability in larch wood; 3. This study reports that some thin or non-cellulosic film substances are deposited on the surface of pit borders, pit membrances and tracheid lumens, that may affect strongly the permeability of wood; 4. The ultrastructure of bordered pits in latewood is very different from that in earlywood sapwood. These bordered pits are small, the tori are thicker and bigger, the diameter of microfibrillar strands of margo in latewood (maxi. up to 3960(?), aver. 1839(?) and 2340(?)) is thicker and wider than that in earlywood (aver. 733(?)), these thick microfibrillar strands consist of several to many microfibrils and are covered by some amorphous substances, the shape of the bordered pit membrane openings in latewood is different from those in earlywood. These may cause the increase in the rigidity of pit membranes and the bordered pits to be unaspirated completely or aspirated partially; 5. The abundent matrix, encrustations and extractives are deposited or penetrated in the different layers of cell wall and around the microfibrils. These substances must block the fine structure and affect the nature of microcapillaries, that may be another main factor of the low permeability in larch wood; 6. This study indicates that the width or distance between microfibrils of the S₃ and S₁ layers is larger than that in S₂, the denseness of S₃ and S₁ is lower, the porosity is higher, especially the S₁ layer is clearer.

The practical calculative precision of non-loading cable system is studied preliminarily by qualitative and quantitative analysis methods in this paper. The approach level of various replaced methods compared with the catenary is studied by qualitative analysis method based on the equation and hypothetic conditions of the catenary. The error value and statistical value of four main parameters are compared through quantitative analysis. The aim is to find out the applicable scope and precision of the main parameters which could satisfy simultaneously the requirements of the cableway engineering design in various replaced methods. The main parameters are central deflection coefficient (φ₀), maximum tension (T_(0m)), suspended length(L₀) and elastic extension (⊿L₀) of non-loading cable system.

Vegetative propagation, as one of the methods for forest tree propagation, has been well known and widely used for almost several centuries, but it is just recently that it has been used in tree improvement procedure for carrying out clonal breeding and clonal afforestation. This paper systematically reviewed its various roles as played in tree improvement works: (1) for preservation of the super genotypes; (2) for establishment of clonal seed orchards; (3) for mass propagation of select clones (plus trees, seedlings, and hybrids); (4) for clonal test and selection of best clones; (5) for screening of seed parents for breeding values; (6) for estimating genetic parameters; (7) for physiological studies and other potentialities of trees.If vegetative propagation is used in clonal breeding, there are some problems which should be considered with caution, such as (1) juvenility and uniformity are two basic criteria for the initial material of vegetative propagation of plus trees in clonal breeding; (2) successive rejuvenation is required to keep the propagated materials in a constant juvenile state; (3) to test the clones in planting application and to select them in the test are the reasonable procedure for clonal breeding; (4) planting of multiclones in plantation is desirable for widening genetic foundation; (5) use hybrid F₁ clones in tree planting represents an attractive approach worthy to be practised in clonal breeding.

Leaves of Paulownia elongala×P. tomentosa were used as experimental material. Plantlets were obtained from MS medium supplemented with 6-BA 4.5ppm+NAA0.2ppm+CH 500ppm.The stem of plantlet was cut off when it reached 2cm in height and was transferred on MS medium with NAA 0.03ppm for rooting. The frequency of rooting is higher on liquid medium with filter paper bridge than solid agar medium. It reached 90% and survived easily when the plantlet with roots was transferred to soil.Histocytological observations on the adventitions buds for mation were also discussed in this paper.

Alnus mandshurica and A. sibirica var. hirsuta are tastgrowing species with ability of N₂-fixation widely distpihuted in northeast in China. Assay of N₂-fixing activity and carbon cost by nodule of the two species was conducted in field and laboratory conditions. Techniques of acetylene reduction and infrared gas analyzer were used in the experiments.Results show: 1) Soil temperature was the major environmental factor affecting N₂-fixing activity of alder nodule. 2. The optimum temperature in N₂-fixation was 20℃ for A. mandshurica and 25℃ for A. sibirica var. hirsuta. 3. Ratio of value of N₂ fixed to CO₂ evolved was maximum at 20℃ for A. mandshurica and 25℃ for A. sibirica var. hirsuta. Efficiency of N₂-fixation at temperature bellow 20℃ was higher for A. mandshurica than for A. sibirica var. hirsuta. But it was reverse at the temperature above 25℃.Measures for increasing soil temperature of site are useful in extending the potential ability of N₂-fixation of alder.

In this paper multi-target fuzzy programming for the constituents of forest tree species in the Baicheng Prefecture of Jilin Province, as well as total area of forest land, proportion of shelter-forest, and ecological and economical target of fourteen aspects, such as, output value, investment, profit, manpower consumption, timber production, fuel wood offering capacity and etc. of an unit area is studied. The result shows that the multi-target fuzzy programming is practicable in making out the plan for the constituents of forest tree species, and by this method, we can make scientific use of land resources, funds for forest manpower and material resources.

In this paper, the authors present three types of tree-crowns upon the eccentric growning of standing trees, i. e. normal crown, sway crown and eccentric crown. As indicated above, a cross-measuring method of the tree-crowns is designed with regard to aspect. A 4m² square control is developed in posting a standing tree as well. It is obvious that the precision and repetition of the methods are much better in tree measurements.

Root rots of China fir, Cunninghamia lanceolata, are caused by Pythium ultimum in pure stands of suitable sites in Sichuan province. The disease starts from the root-tip and extends to the fine roots, then the needles of infected tree turn yellow. After three to four years, the affected trees may be killed. Symptoms are particularly prominent in autumn.

Study on the process of the development of snag and its relationship to the abundance of hole-nesting birds in various forests in Xiao Xingan Ling Mountains shows that, as a part of forest ecosystem, full evaluation of the significance of snag should be made in forest management. Reserving snags with proper diameter and amount in the broad leaved-Korean Pine (Pinus koreaiensis), Spruce (Picea jezoensis and P. koraiensis) Fir (Abies holophylla and A. gracilis), and broad leaved-larch (Larix gmelini) forests is proposed.

This work is aimed at further determining the chemical components of the essential oil from China fir (Cunninghamia lanceolate Hook.). In the experiment the essential oil is obtained by distillating from the China fir shaving and the essential oil is identified with GC/MS technique. The components of the essential oil are further quantitatively determined with two different columns. It is found that there are thirty nine components in which cedrol is a major component and the others such as α-pinene, α-cedrene, α-elemene, β-elemene, δ-elemene, β-caryophyllene, etc., The twenty six new components of the thirty nine components are found and identified by this work, e. i. fenchyl alcohol, α-trans-β-bergamotene, β-caryophyllene, thujopsene, acoradinene, β-selinene, etc.