Study On Forest Structure Characteristics Of Typical Stands Types In North Mountain Of Hebei Province

Structure decides a function, the structure is composed of forest ecosystem elements of an important organizational form. This study In allusion to the Shelter forest structure unreasonable, Ecological degradation problems. function, Studied internal structure features of three typical Superiority species trees (pinus mongolian oak mixed forest, L.gmellini and Betula mixed forest, Pobulus davidiana and Betula platyphylla Suk mixed forest) with the principle of structure decides function.provide the reference for solving the forest ecology construction and forest production. Its main research results are as follows:(1) Using One hectare sample surveys, Investigated and analyzed the characteristics of species composition and diversity, diameter structure, the the height structure. Prediction and fitting height and diameter distributions Using Weibull distribution function. Diameter distribution for approximate reverse "J" form distribution, normal distribution and petronas or the single-peak mountain shape distribution, tree height distribution for normal distribution, approximate normal distribution, the single-peak or diauxie curve distribution.(2) Typical forest trees fractal characteristics research shows that:there are differences in the shape of the crown in three species of forest, the same species differences between individuals of different ages. Acerola crown picture of fractal dimension is greater than the fractal dimension of broadleaf. dahurian larch (1.690)>black birch (1.257)> White Birch (0.997) distribution regularity of the Quantity and Angle are different in different species. Different species of fractal dimension branching pattern is different,the same tree species have different fractal dimension in the same sample plot. This is the result of genetic nature and external environment.(3) Using Mingling index, Uniform Angle Index, Neighborhood Compariso and point pattern analysis method to study the typical forest types community space structure. The results show the Superiority species distribution in various ranks in Mingling, Uniform Angle Index, Neighborhood Compariso. Associated tree had low degree in Mingling index, but have the important meaning to maintain community diversity.(4) The type of plant species diversity is closely related to growth. Species diversity index of herb layer> shrub layer> tree layer; species richness index in variation of the altitudinal gradient is not obvious; Canonical correspondence analysis obtained by the selected sample herbal topography on the order of the degree of influence:aspect> elevation> slope> slope> slope shape.(5) Throughing of spectrum analysis population diameter class analyzes the three stand-order of succession regular:showing that the mixed forest of larch birch, larch, white birch and black birch were the dominant tree species, succession influenced by human disturbance is serious, in aspen birch mixed forest, birch and black birch has a good growth trend.,aspen has the largest number, showing a rising trend,,is the dominant species, it will Success to conifer; in the mixed forest of Quercus mongolica and Pinus, pine is the dominant tree species, seedlings appears a good update, is a typical species of progress,Mongolian oak species belonging to consolidate, the community is approximately the top community.(6) The research of structure provides the basis of theory for sustainable management of forest health,this article combines the research of point pattern theory and the theory of forest spatial structure, the healthy and stable forest structure as constraint, viaing analyze and simulate the forest ecosystem health and Top-level community structure,reach the conclusion that structural optimization model of forest ecosystem;The adjustment of horizontal distribution pattern of trees and species composition and relationship of competition makes the structure of forest ecosystems to achieve optimal.