Study On P.Tabulaeformis And P.Sylvestris Var.Mongolica Artificial Forest Water Production Function And Stand Structure Control Model

In the arid and semi-arid regions, water is the dominant factor in cultivating plantations. Only fully considering the environmental capacity of water resources and building the stand structure management system can maintain the stand stability and get the comprehensive benefits of the plantation, which also may provide the theoretical basis for the distribution of forestry production and stand design and management in the river basin and promote the study on the sustainable development of regional forestry constructions. The author thought that, researching on the consumption characteristics of the forest, setting up the water production functions of the forestry, and then constructing the structure regulation models coordinately may provide the theoretical basis for the distribution of forestry production and stand design and management in the river basin and promote the study on the sustainable development of regional forestry constructions in arid and semi-arid area.The research mainly focuses on the Pinus tabulaeformis and Pinus sylvestris var. mongolica in the Jixian County and Fangshan County of Shanxi Province, Zhangwu County, Fuxin County and Jianping County of Liaoning Province. On the basis of field investigation, sample core analysis and researching on the meteorological data, the author discusses the influence of climate factors on the growth of the two kinds of trees, builds a water production function and sets up a stand structure adjustment model on the basis of water. The results show that:(1) The diameter distribution of the no-thinning stand in Jixian County, all stand density in Fangshan County and the no-thinning stand in Fuxin all deviate the normal distributions, which show that the stand density all surpass the appropriate densities.The species'Shannon-Wiener Index of the whole P. tabulaeformis forest in Jixian County and Fangshan County of Shanxi Province decreased gradually with the increase of stand density. However, when the density of P. tabulaeformis in the western Liaoning province is among730-2430stems/hm2,the impact of stand density on the diversity of under forestry vegetation is quite little. In Shanxi experiment fields, the stand density is the greatest factor influenced the diversity of under forestry plants, nextly under forestry radiation and slope position; and the forest age, aspect and slope are also the important indexes. In Liaoning experiment fields, the space difference of rain play the most important role, meanwhile influence the slope position and slope of the space distribution of water and affect the diversity of plants greatly, but the influences of density is relatively weak.(2) Diameter at breast height and stand density showing a power function both to Pinus tabulaeformis and Pinus sylvestrics var. mongolica.(3) The growth of forest have the regional features, and the consistency and sensitivity of the samples both appear the regional differences; the site conditions such as slope, slope position, aspect, etc. the anthropogenic disturbance of planting and thinning, and the competition caused by planting density all influence the consistency of the plantation samples.(4) Applying the dendroclimate software, the author analyzes the relations of P. tabulaeformis and P. sylvestrics with the two climate factors, local rain and temperature. As a whole, tree-ring width growth are generally a positive-correlation with monthly precipitation of neighboring meteorological stations and negative-correlation with monthly average temperature line in the study area, which is in accordance with the tree growth and climate response pattern in arid and semi-arid areas.(5) The author analyzes the slope aspect distribution features of the guarantee frequency and the available amount of precipitation, studies the consumption characteristics of the forest, establishes a water consumption model of the single tree and stands of P. tabulaeformis and Pinus sylvestrics, comparatively analyzes the water consumption and giving of the specific stands, and explores the time when the balance point of giving and consumption appears.(6) The negative index to the trend and linear detrending are the most commonly used methods, mainly the negative index to the trend, which occupy about70%of the ARSTAN analyzing samples. According to it, the author raises the equations of growth process of a individual tree.(7) On the basis of the curve of single tree growth process, the relation curve of diameter at breast height and density and the relations of wheel width and climate factors, the author structured the water production functions of P. tabulaeformis of the5 experiment fields and the water production functions of Pinus sylvestrics in Zhangwu County.(8) On the basis of establishing water as the main basis and standard of determining the stand structure, the author set up a Stand density model based on the independent variables of water balance, time and precipitation, the model have the format of N=aPcA-b;establish a stand structure adjustment model based on the basic idea of water balance analysis and had a feature of storage model.Finally, from the empirical and experience view point, the author sets up a precipitation-age-density relation model which may be applied to a large geographical space of the two kinds of tree species. These three models solve the relations of the initial density, thinning intensity and thinning time from different aspects.