Study On The Effect Of Mixed Forest Of Chinese Fir And Bamboo In Lingling District Of Yongzhou

Cunninghamia lanceolata is currently the South China's largest planting area,one of the most widely used timber species,but even easily lead to fertility decline and plant productivity decline.The Phyllostachys heterocycla cv.Pubescens is an important forest resources in China,with fast growth,high yield,good quality,wide application,high economic value,high profit,once the success of afforestation,sustainable utilization,is generally difficult to achieve tree species;also in southern China more widely planted tree species and economic species.However,single planting fir or pure bamboo forest has some defects.Since the beginning of 1970s,the rapid development of mixed forest of Chinese fir and bamboo,and made a lot of research,fir and bamboo mixed forest can not only achieve better ecological benefits and economic benefits,but also made use of the mixed forest of forest growth environment and ecological function.This study will be accounted for the proportion of Chinese fir mixed forest is divided into 5 sections of the proportion(0-20%,20-40%,40-60%,60-80%and 80-100%),each set mixed proportions in 3 standard plots,a total of 15 plots,by analyzing the growth regularity of Chinese fir on different mixed proportion CHINAFIR bamboo mixed in,get the optimal mixed proportion of the growth of Chinese fir mixed forest,and then through the model selection of fitting growth model of optimal mixed proportion of Chinese fir,in order to provide a theoretical basis for the proportion of Lingling area in Yongzhou city planting fir bamboo mixed forest,and sustainable management of Chinese fir mixed forest of bamboo to provide the scientific basis,The main conclusions are as follows:(1)Through the analysis of Chinese fir wood diameter,data analysis of different mixed proportion bamboo fir mixed forest in tree height,volume growth,results show that:five kinds of mixed proportion of Chinese fir DBH,tree height and volume growth as the age increases,and the emergence of young forest and middle age forest growth stage soon to process after nearly mature forest stage relatively slow growth;According to DBH,tree height,total volume increment and annual growth rate during the 2-8a analysis shows that the mixed forest of Chinese fir in DBH,tree height growth is the fastest,the volume in the 2-14a period of the fastest growing,overall,mixed forest of Chinese fir in the fast-growing period is about 2-14a,and the characteristics of fast-growing Chinese fir.five kinds of mixed forest of Chinese fir DBH,the proportion of mixed forest in tree height,total volume growth amount is roughly sorted:60-80%>40-60%>80-100%>20-40%>0-20%?(2)The gap between the 5 different mixed ratio of Chinese fir average growth rate is more and more big,the 23a,0-20%and 60-80%compared with the mixed ratio,the average volume growth to reduce the most,78.41%,tree height and average DBH growth were decreased by 33.80%,38.04%.The size of successive growth of 5 different mixed proportion of Chinese fir are:60-80%>40-60%>80-100%>20-40%>0-20%.(3)Based on the analysis of the law of growth of Cunninghamia lanceolate mixed forest in different proportions,it is concluded that the optimum growth ratio is 60-80%.The optimal selection method based on multi model,linear function,two function,compound function(exponential),logarithmic function,S function,power function,DBH,Richards and Logistic respectively on the 8 equations of mixed forest of Chinese fir tree height,the volume growth process of fitting,choose the best model from as the most suitable growth model of Chinese fir mixed forest of fir bamboo mixed forest,and to test the model,Richards equation fitting out the growth of Chinese fir model best fitting precision reached 99%,can more accurately estimate the fir DBH,tree height and volume.The growth model of Cunninghamia lanceolata in mixed forest is as follows:the growth model of Chinese fir DBH:D=48.507x(1-e-0.0039×t)1.,512;The growth model of Chinese fir:H=25.308x(1-e-0.062×t)1.483;The growth model of Chinese fir volume for:V=1.574×(1-e-0.052×t)3 843.(4)Through the analysis of the mixed forest of Chinese fir DBH,correlation between tree height and volume three of DBH,tree height,volume between the three probability p correlation coefficient analysis test value is 0,when the significance level alpha at the level of 0.01 bilateral,three 22 there was a significant correlation between the correlation coefficient between the three;and is greater than 0.8,indicating Chinese fir mixed forest in DBH,tree height,volume three have a strong correlation.