Analysis Of Height-diameter Relations And Competition Factors For Natural Pine-oak Forests In Qinling

Forest growth,mortality and recruitment models has been always a popular technical issue in forestry research.Many forest growth models have been reviewed in China and abroad.These studies provide good guidance and direction for Chinese forestry workers to study and apply forest growth models,and also provide good methods for forest management.This research will be discussed respectively from the site quality and age of tree height-diameter model,the influence of stand level and individual tree level of competition on the effect of mortality and the competition about trees and site quality to influence the recruitment,the results are as follows:Introduction of dominant tree height as the tree height-diameter model of variable factors,and to be the tree height-diameter use the data about Qin Ling 1246 trees of Pinus armandii,419 trees of pinus tabulaeformis and 2007 trees of Quercus.In the usual age of tree height growth and site quality and has a direct relationship,but in the forest mixed of different ages for it is difficult to determine the age of,in this case,we use the dominant tree height as a variable,the site quality and age can represent.By comparing the traditional tree height-DBH model with the model after the introduction of the dominant tree height,and the model of the rank and age groups,it was found that the high energy of the dominant tree was a good reflection of the site quality.Compared with the tree height model established by mathematical classification method,it has good biological significance.The determination coefficient R~2,residual error and average error MRSE were used to test.The results show that the model of height and diameter of trees with dominant tree height is more accurate and can better reflect the growth relationship between the height and the diameter of trees with local tree height.Trying to clarify the influence about stand and individual tree level competition to the mortality of QinLing natural secondary forest,the effects of tree size,canopy size,the unit number and size of tree relationship of trees such as the influence of low loss,and introduced by the size of the space distance of the trees and trees relationship to the research on the rules of withered trees damaged.Thus using the size order and BAL,CCF,SDI,four different size score competition index of the trees to get mortality in stand level,tree list level and individual dynamic change of stand.This let us data acquisition and analysis of the difficulties,thus this article,we will order 6 cm diameter as the diameter in order to discuss,this study aims to discuss the site quality stand and individual level of competition process,and influence on into the community,for the screening of a few wood will react in stand density,canopy factor,and the size of the tree diameter at breast height,and competitive factors related to the distance of statistics and discuss.The law between the recruitment and the mortality,the occurrence of the recruitment under different competitive conditions and the effect of the site quality on the recruitment are obtained.Try to estimate a recruitment model.