On the basis of the results from the geographic provenance test of nine years oldlarix olgensis in Liangshui Natural Reserve of our university, a study on the geographic varition and the primary selection of the best provenance ofLarix olgensis was carried out. The main results are as follows: I.The different provenances ofLarix olgensis have rich and wide genetic variation, and exist a linear correlation with latitude and longitude in collection area. General trends are enumerated below: Provenances at lower latitude and more west longitude have lighter thousand seed weight, short growth period, higher increment, wide branches, rich leaves and crown as well as worst adaptabillity. It is a dual-way variation along with two directions of latitude and longitude, and also embodies a change gradually in climate condition from south to north. The temperatures in seed production site, especially the mean temperature in January and ≥10 °C accumulated temperature, are important factors that produce geographic variation forlarix olgensis. 2. The variation of different provenances in periodic biological phenomena and growth rhythm trends are that: 1 both of the provenances from Changbai Mt. (III) and Dashitou(IV) at low latitude belong to the centralized growth type, and have shout growth period, the difference between these two provenances is that the provenance from Changbai Mt. grows well in all time, Dashitou provennce is well only in later period; 2 the provenance from Baidao Mt. (II) at middle latitude belongs to even growth type and has longer grpwth period, this provenance has higher increment in early and later periods relatively; 3 Xiaobeihu provenance at high latitude is a growth type among II. III and IV provenances and has a general growth period, the provenance grows better in middle time and worse in later time. 3. The best provenance in Liangshui Natural Reserve and its meighbourhood is Dashitou Procenance, which growth in height, diameter and volume has exceeded 16. 28%, 46. 27%, 30. 58%, 78. 20, 82. 00% as well as 392. 00% by comparison with the mean value of the contrast and the worst provenance respectively, The result from the height growth of three, five, seven and nine years oldLarix olgensis by using the method of order correlation analysis demonstrates that it is possible to make early selection of the provenance. Meanwhile, data from juvenile and mature oflarix olgensis plantation also prove the reliability of the early selection. 4. The provenance heritabilities of nine years oldlarix olgensis in Liangshui Natural Reserve are follows: The heritability of the height growth (h2) is 0.79; The heritability of the diameter breast height (h2) is 0.791; The geretic gain is 24.5% and 40.36% respectively.
The height fast growing period of oak seedling (Quercus mongolica) was between 25 to 30 years old but the diameter varied greatly. The maximum diurnal height increment of the investigated oak tree reached 3.3 cm, but at daytime it was much greater than at night. The oak trees usually sprouted twice and even treble in the growing season. In natural oak stands, the volume rarely exceeded 200 m3/hm2 and the mean volume increment was only about 2 m3/hm2
Evapotranspiration of a natural secondary white birch (Betula populifolia) forest in Maoershan Ecological Station was determined by water balance method, heat balance method and water and heat combination method. Results showed that the total evapotranspiration of the forest in the growing season was 3.6mm/d, of which evapotranspiration from canopy was 2.91 mm/d and that from forest floor was 0.57 mm/d, and that in the non-growing season was 0.8 mm/d.
According to the study on soils under the 34-year-old Larch forest and Larch-Walnut mixed forest, It was concluded that, in mixed forest, the total content of water-stable aggregate (0.25–5mm) in the upper layers (0–30cm) of soil was significantly higher than that in pure forest. The 2mm aggregates increased 48% in mixed forest soil compared with pure forest, and consequently, the three-phase ratio of soil was regulated, the physical properties improved and the fertility of soil raised. Because of the stability of total aggregate content and the importance of 2mm aggregate content in soil fertility, it’s advisable using the two indices above to characterize the effect of mixed forest on soil improvement.
This paper is the first of a series dealing with morphological characteristics, biological cycle and damage importance of insect species newly identified as cone and seed pests in Northeastern China. The spruce cone mothBarbara fulgens appears to be a serious pest of korean spruce cones in Heilongjiang province.
In 1991, in Daxingan Mountain, an outbreak of larch caterpillar (Dendrolimus superans Butler) happened on large areas of more than one million hectares, where stands of larch were seriously damaged because needles on the trees were almost eaten up by the pest, causing enormous economic losses. Analysis of data collected indicated that the main cause of the outbreak of larch caterpillar on large areas was that, after thirty years of exploitation, mature and overmature forests decreased rapidly, middle-aged and young forests incresed in large amount, significant changes occurred in individual ecological conditions of stands, especially those tended, with decreasing canopy density and better light condition in the forest, and all these were adventageous to the outbreak of the pest. In addition, in recent years, the climatic condition in Daxingan Mountain changed significantly. The yearly average temperature raised gradually and the soil surface temperature in April and October increased year by year, which were advantageous to the outbreak of larch caterpillars. In short, the significant changes in the ecological conditions in Daxingan Mountain provided suitable conditions for the outbreak of the larch caberpillar, and after several years of increase in population number, the larch caterpillar outbroke into a serious disaster on vast areas. In the paper, composite control strategy was also discussed.
Forest fire occurrence is closely relative with fuel water content. There are a lot of research about dead fuels, but forest fuels consist of both dead fuels and living fuels. Each large fire occurrence has a good relationship with living fuels. Especially living fuels can influence the production and development of big forest fire, so, we selected Tahe, in Daxingan Mountains, as observation site. According to actual data, we can establish a set of models of different living fuel water content variation with linear-regression method.
In this paper, the equations of tree growth stresses are given by using thick-walled cylinder theory under the assumption that tree trunk is considered as a homogeneous orthogonal anisotropic cylinder. Through a lot of calculation of the experimental data, some figs of growth stresses’ distributions are given, and growth stresses distributions are analyzed.
Rational measuring design of the tree length is a course to optimize all position of it before bucking. This paper offers the weighted digraph in the digrams and theories to solve the optimal problem of rational measuring of tree length based on experts’ researches in home and foreign. Sawlines are defined as apexes xd, log between two sawlines as a side yn, the price of log as weight Wij. It can describe the digraph of the rational measuring design of the tree length T = (X, Y, Wij), which consists of point-set and side-set. Oweing to Wij> 0, using Mr. E. W. Dijkstra’s theory, we can obtain the “path” of maximum profit of the tree length under the best availability of the tree length.
Under the condition of absolute dry, more than thirty forest fuel parameters, ash content, extract and burning point were measured. By the method of regression step by step, we found an experience formula which can estimate effective fuel high combustion value of forest community from the Daxingan Mountain, and then, By means of modifying moisture content, we gave an approximate formula about actual heat releasing of forest fuels in the forest fire behavior.
The dissolution of lignin and major ploysaccharides from sulfonated chemimechanical pulp (SCMP) ofL. gmelini during sulfonation and defibration, the tharacteristics of lignin and bleachability of larch SCMP were studied using gas chromatography (GC), IR, UV spectrometry, ’H-NMR, “C-NMR and chemical analyses.
The parallelism of saw guide motion locus against the blade is one of the main items in the testing of the geometric precision of the whole woodworking band sawing-machine. It reflects the making and mounting precisions of the sawguide device, having a direct effect on the working performance, the saw timber quality, and the safety (nature) of the woodworking band sawing-machine, so it is of great importance in the testing process of the band sawing-machine assembly and their going out of the plant.
This paper summarized the previous researches about resin efficiency of particleboard in the world, and introduced the computer vision (CV) technique on resin efficiency, which has the properties of high measuring speed, automatic pattern recognition and low environmental requirement, etc. The theory of the CV technique used for resin efficiency in particleboard was studied, along with the handling of resined-particle images and the gathering of relative gray image features. Some quantitative parameters describing the resin efficiency of particleboard were established, and the results indicated that the computer vision method on the resin efficiency was much better than others and can control the producing of particleboard more effect.
In this paper, the relationship was studied bwtween the permeability of Pinus koraiensis, Larix gmelinii, Betula platphylla and Populus davidiana and moisture content of wood in the hygroscopic range. The mathenatical model of variation low has been obtained from the relationship between wood and water, The results are as fellow: (1)The relationship betweed wood permeability and the moisture content is in twice curve function in the hygroscopic rang. (2)There is a peak value in tangential permeability, (3) The number of openings per cm of cross sectionand pit—opening average radii reduces by the increaasing of wood moisture content.
The wood powder ofTetracentron Sinense Olive was extracted with the benzene and alcohol (2:1 v/v). Then, the extractive is analyzed in Gc and Gc-Ms. Twenty chemical constitutions of the extractive are separated and identified, which are as follows: calamenene; 2.6,10-trimethyldihexyl; 3-methoxybenzaldehyde; Methyl-4-methox-ybenzoate; 4-methoxyphenylacetone; 3.4-dimethoxybenzaldehyde; 3.4-dimethoxyhypnone; methyl-3.4-dimethoxybenzoate; Methyl-4-methoxyphenylacrylate; 4,4′-dimethoxycabonyl-diphenylethane; Methyl-3, 4,5-erimethoxybenzoate; Methyl-3.4-dimethoxyphenylacrylate; Methyl-myristate; Methyl-palmate; Methyl-zoomarate; Methyl-stearate; Methyl-oleate; Methyl-arachidate; Methyl-behenate; Dimethylazelate.