On the basis of the data of provenance test for 10 years in the total natural range ofLarix olgensis from 10 seeds collection sites, the geographic variation patterns have been made by means of canonical correlation analysis: (1) The basic variation patterns of growth characters is in vertical gradual change along the elevation gradient as principal, and gradual change along the latitude as supplement. (2) The Xiaobehu provenance with low elevation and low equivalent latitude is the good gene resource center ofL. olgensis. It has the genetic characters of rapid growth, high stability and fine timber quality. (3) The synthetical interaction between water and heat factors is the major factor to produce the variation ofL. olgensis and the temperature is the principal one. (4) Among the genetic variations of geographic population characters, the variation of growth is the most obvious one, and it could be taken as the main character for provenance division. (5) By allocating the seeds from the low equivalent latitude region to the northern suitable afforestation areas, the greater genetic gain could be obtained.
This paper studied that the significant difference exists among the ten provenances of 9-year-oldFraxinus mandshurica stand. The rule of geographic variation is that dual continuous changes with longitude and latitude, and the provenance in the southwest range grows rapidly. There are positive significant correlation when the tree growth is influenced by ≥10°C accumulated temperature, duration of sunshine and annual precipitation. So it is suggested that Lushuihe and Maoershan provenances should be employed first in Maoershan Forest Farm and its neighborhoods.
An investigation of seed germination and early seedling growth ofEucalyptus microtheca was based on seed collection from 10 widely separated provenances in Australia. Genetic variation of seed germination and early seedling growth was observed among a series of provenances whose natural habitats range from different climatic condition. In the ten provenances, both the model of seed relative germination percentage and the model of seed total germination percentage fitted Logistic regression [y=a/(1+exp(-ex+b))]. In comparison with provenances from four high temperature (mean annual maximum temperature >30.0 °C; mean annual minimum temperature >17.0 °C) areas, six low temperature (mean annual maximum temperature <30.0 °C; mean annual minimum temperature <17.0 °C) areas showed the fast germination rate and the high total germination percentage. For each provenance we have 45 seedlings equally divided into three watering levels (100%, 50%, and 25% of field capacity), and studies on relationship between early seedling growth and climatic factors of the natural habitat of provenance. In control treatment, height growth of the seedling has been associated with intrinsically the driest quarter precipitation in the seed collection areas of provenance. In all the treatments, length growth of the biggest leaf of the seedling was related to mean annual maximum temperature and mean annual minimum temperature in origin of provenance. In contrast, basal diameter growth of the seedling was related to mean annual minimum temperature of the seed collection areas in water stress treatment. From an ecological viewpoint, the fast germination rate and the high total germination percentage of the seed and rapid early growth of the seedling appear to be favourable adaptations to the climatic conditions prevailing in the natural habitat of provenance.
The main characteristics of energy environment, energy products, primary productivity and basic process of energy flow for three-hardwood forest (Juglans mandshurica, Fraxinus mandshurica, andPhellodendron amurense) were studied. The research was mainly based on the theory and method of community energetics, dealing with fixed position, quantitative test and experimental analysis. The time-space dynamics of sun-radiation in three-hardwood forest were meansured and the energy compartment model was set up. his research work provided a scientific basis for the exploitation, utilization and management of three-hardwood forest.
In order to study the dynamics of uneven-aged stands of interior Douglas-fir,Pseudotsuga menziesii var. glauca (Mirb.) Franco in future, six permanent sample plots were set up on the Knife Creek Block of the Alex Fraser Research Forest of University of British Columbia. The measurements and observations for all living trees within the boundaries of a plot were made, including DBH(diameter at breast height), TTH(total tree height), height to lowest living branch, crown diameter, tree vigor, angle of lean, distance of lean, direction of lean and tree location. Based on the data, some stand characteristics of the plots were analyzed simply and preliminarily. Results showed that most of the interior trees on the plots are ranged 10–20 cm in distribution of DBH class, and 2–6 m in distribution of TTH class. Trees with different sizes, however, are distributed unevenly. The relationship between total tree height and diameter at breast height follows a quadratic distribution, Y=a+bX+cX2.
The development characteristics variation of the vegetative structure in the different morphotypes trees crowns are regarded as a result of the genetic differentiation and environment interaction. The morphohysiological characteristics and the evaluation of their function in meaning the morphogeny of different sex and position of crown shoots are used to reveal means of morphotype forming inPinus sibirica. It has been found that the differences of activity and direction was changed of shoots growth characteristics in ontogeny of trees with different growth and reproductive activity, and that the size of the individual meristematic layer in the vegetative and generative apex differ and increase with its age. Transmission from vegetative to the reproductive stage in contrast of age modification is correlated with the sudden increased of the medullar parenchyma size. Thus the intensification of mitotic activity in the medullar zone of the apex and the increase in apical size precedes the shoot feminization. The large activity of stem unit which correlated slightly with its unit stem change is inherent in the male and asexual tree morphotypes.
The paper summaried the researches on the conifer woolly aphids in northeast and southwest of Chin, and briefly described the life cycle and economical significance of the species and 1 subspecies of the Chinese conifer woolly aphids.
There are three species of bears in China, brown bear (Ursus arctos), black bear (Selenarctos thibetanus) and sun bear (Helarctos malayanus). From 1991 to 1994, the investigation of bears organized by CWCA (China wildlife Conservation Association) was conducted in 22 provinces of China. The results showed that the distribution area of bears had been changed from the continuous distribution to fragmentary. The distribution areas of three species were limited to the area of 2591427 km2, and the total number of population was reduced to 61686. The distribution area of black bear was 625086 km2; the population size was 46528; average density was 0.0714/km2. The distribution area of brown bear was 1956691 km2; the population size was 14783; average density was 0.0076/km2. The distribution area of sun bear was 9650 km2; the population size was from 350 to 400. There are 396 bear farms in China and the 6688 bears are being reared on these bear farms 94.4% of them is black bears (3612); 4.5% of them is brown bears (300); 1.1% of them is sun bears (10). The management of bears in China was discussed in this paper.
Siberian tiger (Panthera tigris aitaica Temminck) is the largest cat in the world. The wild population is about 250. The population in China decreased from 120 in mid 1970's to less than 20 now. Hengdaohezi Felidae Breeding Center was established in Heilongjiang province in 1986. The Siberian tigers were fed artificially and were trained to reintroduce primarily. The population increased from eight to seventy by hard work for about ten years. In the meantime, the researchers have done much research work on physiology, biochemistry, breeding, behavior, disease prevention and so on, they have got much valuable information of tiger population. In January, 1996, “Siberian Tiger Park” was built on the east side of The Sun Island in Harbin. The China's unique and the world's largest Siberian Tiger groups are being domesticated here. Because of the change of the living condition, the focal point of the tiger population management is now to reintroduce the tigers. So, the tigers are being trained to learn how to pery in the wild, how to adapt the bad nature environment and increase the ability of disease prevention. Tourists can enter the park by tour bus or by their own car. The income of the park tickets can be used to build the park and develop the tiger population. It is a good opportunity to increase the consciousness of Man's protecting wildlife. The large carnivores can coexist in the world with Man.
The inhibitory effect of crude extracts of garlic, clove and carrot at concentrations of 20,000, 40,000, 60,000, 80,000 and 100,000 μg/mL on growth ofAspergillus flavus and aflatoxin production in rice was investigated. The results showed that garlic, clove and carrot could inhibit the growth ofA. flavus and aflatoxin production. Garlic and clove at 100,000 μg/mL highly reduced the level of aflatoxin from 5.94 to 0.15 and 0.06 μg/g respectively whereas carrot at 20,000 μg/mL reduced the most level of aflatoxin from 5.94 to 0.03 μg/g. Garlic, clove and carrot at 100,000μg/mL also inhibited the mould growth. The most effective herb for inhibiting the growth ofA. flavus and aflatoxin production was garlic.
All these hosts became less susceptible as the plants matures. Ascospores were unable to infect linseed leaves in the absence of an exogenous nutrient base. Even though sucrose could be used as an exogenous nutrient to stimulate the ascospores to germinate, the ascospores subsequently failed to infect undamaged linseed leaves. Linseed flower petals were an effective nutrient base which stimulated ascospores to germinate as well as to infect undamaged linseed leaves.
By analyzing the existing average skidding distance formulae and the shape of the landing area, the authors put forward that the average skidding distance is the shortest when the ratio of length and width is 1, and the landing collection area is in proportion to of average geometrical skidding distance. The new models of calculating average distance are presented.
Forest ecosystem is one of the most important ecosystems in the world that human-beings rely on. Forest harvesting policy is one of the main criteria indicating how and how much the human beings open up and make use of forest. Whether the policy is reasonable or not has high relations with not only the increasing or decreasing of forest system, but also the development speed of human society. In this paper, the author analyzed the development of interaction between human society and forest ecosystem from ancient times to today. Then author stated that the rational harvesting policy should be the harvesting sequences of both harvesting density and harvesting time, which might result in the maximum comprehensive benefit, including economical profit, social benefit and ecological benefit, of forest to human society. At last, according to the analysis of interaction between human-beings and her environment, the prediction analysis for human society development in forest regions in the future was presented using Entropy Growting Analysis.
Although quite a number of papers can be found up to now dealing with the subject of the measurement of wood density by using the X-ray exposure methods, direct scanning or radiographic photography, the following two aspects, which are very important from both theoretical and engineering application points of view, have not yet been properly handled. One is that the elementary analyses or the experimental measurement on the mass attenuation coefficients were not specified in regard to spectrum energy distridutions(1). In this connection, the ambiguities in the specification of the coeffiecients and in turn for the results among studies arise when only one of the two parameters, namely wave length and applied voltage, of defining the energy spectrum of X-ray is given. The other is that the relationships between the relative intensity and the sample thickness as well the wood moisture content(2), which are the critical factors for the design and the selection of X-ray apparatus, were not sufficiently examined. In addition, the knowledge of the measurement of wood miosture content by using the direct X-ray scanning method is also almost unavaible now. In the study, the direct X-ray scanning method of measuring wood moisture content was at first investigated theoretically with respect to the relationship between the mass attenuation coefficients of wood (beech,Fagus Sylvatica) and the maximum spectrum energy of X-ray. Secondly, the dependence of the relative intensity on the sample thickness and on the wood moisture content was analysed. The main advantage of the method is on-site nondestructive measuring of wood moisture content in the processes such as drying, impregnation and unsteady mass diffusion. Specifically for the application in the area of biomechanics, the method can also be used for understanding the water pathway within wood, for example, the water around the knots and the relation between the stress distribution and the local moisture content of wood.
A number of references about the degradation of particleboard strength were reviewed. Evidences indicate that PF adhesives are hydrolytically stable and yet particleboards bonded with these resins still degrade. The main causes of degradation of PF bonded particleboard are the reversal of densification and the development of glue line stresses.