Study On The DBH Growth Law Of The Forest Species With Topography Space

Forests are the earth’s largest terrestrial ecosystems, with important economic value, ecological and social values. It not only provides a wealth of mankind forest products, but also for the regulation of climate, water balance, purify the atmosphere, soil fertility improvement, and recreation of residents played a huge role. Scientific management of forests and the management needs to understand the status and population trends of forest populations of the operating area. Due to changes in forest populations greatly influenced by the environment, growing age of the tree will generate difference in the different environment, particularly affected terrain (elevation, slope position, aspect, slope), and thus establish populations DBH growth model based on the topography of space variability of populations is very necessary. This paper studies a representative population in the sample plots, such as pine, spruce, fir and brich for the study.Firstly,in this paper, the theory by two-way ANOVA repeated tests, analysis of the study plots various topographical factors for various populations of different diameter DBH growth effects, results show that:study plots of Korean pine, spruce, fir, rare species and birch trees in each diameter class of DBH growth differences due to changes in terrain factor, which has little effect on growth of DBH altitude group, and slope position, aspect and slope changes of the various groups there are significant differences in the amount of influence DBH.Secondly this paper use the theory of nonlinear regression to establish population DBH growth model based on the topography elements in the topography space, the population model chosen is quadratic curve model. Look from the regression test, the model basically reflects the change rule of various group of DBH growth in various topography factors. Built from various group of DBH growth model can be concluded that, in general is Korean pine, spruce, fir and precious tree species in early age slower growth of diameter at breast height, DBH growth gradually increased with the increase of diameter at breast height, when reached the age of a certain stage, will decrease with the increase of diameter at breast height and DBH growth gradually, and white birch is in early age DBH growth faster, DBH growth gradually decreases with increase of diameter. Different topography elements will make DBH growth slightly change. This paper built the population DBH growth model can be used in the same condition of forest land, but using a scope limited to the scope of each model images respectively.