Quantify The Spatial Structure Of The Loess Plateau Cai Song Community

Spatial structure means the interactions among individuals or subjects in the space as well as the spatial aggregate based on it. Forest spatial structure can be defined as spatially assembling degree and shape which are formed by the interactions among all the individuals of forest plants. The spatial structure of forest reflects the interactions among plants, which is a organizational form for the distribution elements in forest ecosystem.Pinus tabulaeformis f. shekannesis is the varietas of P.tabulaeformis, It distributes on the middle part of Loess Plateau. It is a peculiar species which only be found on Loess Plateau. As the constructive species, Pinus tabulaeformis f. shekannesis is superior to P. tabulaeformis on reproductive cycle, reproductive performance, the seedling survival ability. It grows faster to become a timber than P. tabulaeformis. Pinus tabulaeformis f. shekannesis has a tall body, a straight trunk, natural pruning and soft material quality, which will be more easily for managers to get a bigger timber.The research method for forest spatial structure can be checked through analyzing the spatial structure of Pinus tabulaeformis f. shekannesis, the scientific statistic for the protection and nurturing of Pinus tabulaeformis f. shekannesis communities can also be provided.Based on divide the three-dimensional spatial structure, from the basic situation of communities (one-dimensional studies), community distribution (two-dimensional studies), community spatial heterogeneity (three studies) on the Loess Plateau, pine wood (Pinus tabulaeformis f. shekannesis) Community A quantitative analysis of spatial structure, the results show that:1. the basic species composition of pine wood:oak (Quercus liaotungensis):other species=7: 2:1, diesel pine dominate in the community, and population structure of pine wood good population trends are good updates. Dense understory vegetation, shrubs grow well, some shrubs have entered the tree layer; to Zoysia grass Carex (Carex rigescens), Kentucky bluegrass (Poa) mainly firewood pine seedlings and the number of large oak seedlings, but does not cover large.2. Community level of the tree layer structure of space-like distribution of group shows, gathering firewood for the distribution of pine communities; population size differentiation of pine wood is more homogeneous and stable tree layer species, pine and oak wood to gain a competitive advantage; wood pine species mingling index lower degree of isolation between the pine wood is very low, strong intraspecific competition; wood pine species diversity of the vertical gradient of the largest populations of pine wood vertical space usage on the highest, most complex structure of vertical space.3. Chai loose spatial heterogeneity of larger, more complex spatial unit structure, relatively large differences between individual trees, with the Chai Songsheng long, population value of the performance of a certain law of SCI; oak spatial heterogeneity of the population is relatively small, small differences between individual trees. SCI values of the two species, the trend reflects the degree of utilization of space of species and their different life history characteristics.In this paper, loose community structure of wood based on the analysis of spatial structure index to do further research:1. By DBH and tree height of the underlying index, DBH and tree height growth advantage in performance, population updates have consistent trend, in practice more convenient, we can use the index instead of measuring the diameter of tree height index.2. Using Voronoi diagram and Delaunay triangulation structure calculation of the horizontal distribution pattern of community and traditional 4-neighborhood method has high consistency, but the Voronoi diagram and Delaunay triangulation structure directly reflects the level of community distribution patterns, and better reflect the The relationship between the individual trees.3. Spatial heterogeneity index of SCI to be more accurate and complete expression of the community structure changes in the characteristics of the expression of community structure and on the advantages of accurate interpretation of population and development, future development and application has broad prospects.