Four alternative functions are used for fitting tree height and diameter growth models for mongolian oak. (Quercus mongolica Fisch. et Turcz.). The data set includes 1250 random trees and 755 dominant trees coming from 510 temporary plots. The resultsshow that the Richards function is the best model for predicting height. diameter at breast height (DBH) and dominant height from age. The average growth curve of dominant height is used as a guide curve for the construction of a site index table which is partially validated using an independent data set. The Mitscherlich function is the best model for estimating height and dominant height from DBH.

A transformation system was established for loblolly pine (Pinus taeda L.) mature zygotic embryos usingAgrobacterium tumefaciens. The gene coding for the β-glucuronidase (GUS) gene was introduced into loblolly pine tissues and its transient expression was detected with histochemical staining. The influences of different genotypes.Agrobacterum concentrations. and cocultivation time on GUS expression and kanamycin resistant callus and shoot regeneration were investigated. The results showed that the highest GUS expression frequency (16.3%) and shoot regeneration frequency (78%) were obtained from genotype 9–1003 withAgrobacterium concentration decreased 9 times and cocultivation time of 56 hours respectively. GUS expression was obtained in all genotypes tested. The successful expression of the GUS gene in different genotypes suggested that it will be a useful transformation system for loblolly pine.

Horizontal and vertical distributions of fine root abundance (mass per unit ground surface area) were investigated in a densely planted larch-ash-stripe-mixed forest on dark brown forest soil in northeast China. There was evidence for some degree of below-ground niche partitioning (or differentiation) between the two species in both the horizontal and vertical directions. The ash fine roots largely penetrated into the larch belt (larch sub-community) in surface soil (0–20 cm). indicating a possible inductive effect of larch ecological field on ash roots: while the penetration of larch fine roots into ash belt (ash sub-community) was much restricted, which reflected a negative influence of ash ecological field on larch roots. In the vertical direction of marginal soil, the ash fine roots were mainly distributed in topsoil with a vertical gradient similar to that as in the internal ash sub-community, but the larch fine roots were relatively compelled to deeper soil layers by the competition (or exclusion) of marginal ash trees. All the differences or complementarity were considered to the result of interspecific competition, which was important to the coexistence of the two forest species and the sustainability of mixed plantation.

Larix olgensis is a major reforestation species in areas of the northeast part of China. Rooted cutting for vegetative propagation on this Larch has been carried out since 1990, and later the bulk method of hardwood cutting propagation also has been studied. The result is as follows: (1) Cuttings from physiologically juvenile trees are easy to root, and develop better roots. In addition, there are many methods to enhance the cuttings rooting. (2) The good time for seedling transplanting is in the middle of August. Treatments with plant hormones and rare-earth compounds can improve the seedling survival rate, and the survival rate of the seedlings soaked in chelate rare-earth molybdenum compound (300×10⁻⁶) for 3 hours reached 94.00%, 19.49% higher than that of the control. (3) Methods of maintaining juvenility such as hedging, is essential to further developments for operational planting of vegetative propagates. Hedges in 5 years old can produce 91.75 shoots per tree, exceeding the control to 152.2%.

Through studying seven analytic trees from two stands ofPinus koraiensis artificial forests, the results show that the individual variation coefficient of tree heigh, dbh and volume decreases with age increasing after age of 25. Age of 25 is the age that difference of individual growth is from acute difference to comparatively stability. The optimum selection age is 25a forPinus koraiensis’s artificial forests according to the analysis of juvenile-mature correlation, and early selection efficiency.

This paper dealt with the studying the germination percentage, germination potential and analyzing the germination of the seeds with different treatments by systematic statistics method. Seeds were collected from 14 provenances in September 1994. The results indicated that the germination percentage and germination potential of the seeds in various provenances were different. Both indexes in Nanchang, area was much lower than those in the rest provenances. The germination percentage and germination potential of the seeds in different provenance declined after the seeds were treated with aging for one year. The light treatment might promotes the germination percentage more effectively than the germination potential. In addition, fuzzy cluster may reflect the relationship among germination in different provenances.

The stem analysis ofBetula platyphylla in natural forest at the Maoershan Forest Experimental Station of Northeast Forestry University, showed that the growth variation of the trees, including height and diameter breast height, decreases with the increase of the age. There is the turning point for the growth variation of the tree from acute change to relative stability when the trees are in eighteen years old. There are significant differences among the height, diameter and volume growth of the trees at that time. Therefore, the optimal age for early selection of this species in natural stands is eighteen years old (18 a). Diameter is used as main index for selection and height growth as auxiliary one.

In this paper, four species ofEncarsia Foerster collected from northeastern China are reported, and a key is given for females. Except.E gigas (Tshumakova), most of the species are first time reported in this region.

Dendrolims superans produced one generation every two years. Large larvae and small larvae exist at the same time. It broke out in Daxiang an Mountains in 1990, and seriously destroyed growth ofLarix gmelini Rupr. In order to controlD superans, the population properties ofD superans were studied from 1991 to 1992, including sexratio, age distribution, pattern etc.. The sex ratio ofD. superans population is ♀∶♂ − 1.06:L. The larvae age distribution indicates that larvae over 5 instar is less than younger larvae under 4 instar in Yongqing forest farm, but the younger larvae under 4 instar is more than larvae over 5 instar in Hanjiayuanzi Forest Farm. The population ofD. superans in Yongqing Farm has been declining. and mereasing in Hanjiayuanzi. Pupae and eggs are mainly distributed in middle and lower crowns layer of trees respeetively account for 66% and 59.5% of total individuals. The pupae in higher crown layer is lightly regular distribution and clumping distribution middle and lower crowns layer of trees. The eggs in higher crown is light clumping distribution and random in middle and low crown of tree.

Inoculation experiment was made for 15 poplar species to determine their resistance toMarssonina brunnea by the agar leaf-dise technique and the water-culture shoots technique. The results show thatPopulus simonii andP nigra var.thevestina are very suseeptible to the disease:P. davidiana andP. koreana are slightly resistant to the disease:P. ussurrensis has high resistance, and the others remain moderate resistance. Experiments are also made for healthy leaves to analysis the inorganic element content and water content. And the results show that the contents of Fe and Ca are remarkbly negatively related to the resistance of poplars toMarssonina brunnea.

There are five species of swan in the world. Three of them were recorded in China. They are whooper swan (Cygnus cygnus), whistling swan (Cygnus columbianus) and mute swan (Cygnus olor). Among them. whooper swan is the most famous in China. Whooper swan is a resident bird in China. They breed in Xinjiang Ugyur Autonomous Region. Inner Mongol Autonomous Region. Heilongjiang Province. etc., and winter in Qinghai. Shandong. Henan Province, etc, and the lower reaches of the Changjiang River. The total number in China is about 5.000 in breeding grounds and 15.000 in wintering grounds. Higher number were found in 1960s. Because of the changes in environment and hunting, of picking up eggs and of catching nestlings, their population is being reduced rapidly. They are in danger now. In order to protect the whooper swans, some protection measures must be taken, such as strengthening public education and scientific research, estabilshing a base of raising and breeding: developing international cooperation, strengthening the construction of natural reserves in the breeding and wintering grounds. Up to the end of 1993. 34 natural reserves have been established in China.

There are 16 species of fleshy-fruit cating birds in Autumn in Maoer Mt. NE China. According to their feeding strategies. we can divide them into 3 groups: 1. Pulp-cating birds, they get nutrition from pulp. so. their seeds are defecated completely. These birds have a great effect on seed dispersal. 2. Seed-cating birds, they obtain nutrition from the seed but pulp. Seeds are digested totally. They don’t disperse seeds at all. 3. Whole-fruit-eating birds, both seed and pulp are digested when passing through gut. They don’t have any effect on seed dispersal either.

Fast Fourier Transfer Image Processing was widely applied to the analysis of wood amatomy structure in recent years. The cells in the wood transverse section have obviously periodicity and regularity. FFT power spectral patterns can extract the periodic characteristics so that they can be compared. identified and classified quantitatively. This paper summarizes the application of FFT image analysis in wood science and the general way to study wood anatomy by FFT.

The surface profile behavior of workpieces sawn has been investigated. Six species were sawn under the condition of four different kinds of cutting speed by the band saw. The real surface profile of a sawn workpiece is composed of two sections, which are the additivity of the waviness of filtered wave and roughness curve. The roughness of center line average as well as amplitude decrease with the increasing of cutting speed for different kinds of species used in the experiment.

Based on the special molecular structure of surfactant, paramagnetic material used as magnetic nucleus was coated with two layers of surfactant including an inner layer and an outer layer. Magnetic reagent can combine with activated carbon due to adsorption of hydrophilic raclical of the outer surfactant layer. So activated carbon has magnetism. The effects of magnetic reagent dosage pH and activator upon the magnetic susceptibility of activated carbon were studied. Concerning the optimal conditions. MR-20 is the best magnetic reagent. Concentration of CaCl₂ is 0.02M and pH 1.8–2.4. The physical properties of magnetic activated carbon vary with the types, dosage and magnetizing condition of magnetic reagent.