Tree Growth Regulation And Compatible Biomass Model For Individual Tree Of Natural Secondary Phoebe Bournei Forest

As a unique species of China,Phoebe bournei was national gradeⅡkey protected plant,which has important ecological and economic value.Based on the research area of Anfu county in Jiangxi province,this paper took natural secondary Phoebe bournei forest as the research object and obtained the data by means of typical sample investigation and stem analysis.According to the value of Hegyi competition index,the analysic woods were divided into type 1,type 2 and type 3.Growth regulation,growth mode and establishment of related management tables of Phoebe bournei was studied in this paper.Biomass allocation patterns of total tree and each component（stem,root,branch and leaf）of Phoebe bournei were analyzed.Furthermore,the influence of tree competition to biomass allocation of total and each component of tree were discussed.Compatible biomass models were established by using nonlinear measurement error model.The results would provide scientific basis and theoretical reference for formulation of management measures and prediction of the natural secondary Phoebe bournei forest.In addition,the results could also provide reference for the management of natural secondary Phoebe bournei forest in other region.The main results and conclusion were as follows:（1）The fast growing period of annual increment of diameter at breast height（DBH）of Phoebe bournei was during 30^th-50^th year,the highest value of current annual increment was 0.57 cm.There were two fast growing period of annual increment of tree height,which were during 5^th-20^th and 35^th-45^th year,the highest value of current annual increment was 0.37 m.The current annual volume increment curve and mean annual volume increment curve didn’t meet in 65 ^th year,indicating that the forest didn’t reach its quantitative maturity age.Each kinds of increment of DBH and volume showed that type1>type 2>type 3.The total volume increment of type 1 was 3.7 times more than that of type 3,the total DBH increment of type 1 was 1.8 times more than that of type 3.There was no significant difference between each type of tree height and volume growth ratio.The best equations to simulate the growth process of DBH,tree height and volume of Phoebe bournei were Richard samely.The best equations to simulate the growth process of each type of DBH were the equations of Gompertz,modified Weibull and Gompertz in respectively.The best equations to simulate the growth process of each type of tree height were the equations of Richard,Richard and Gompertz in respectively.The best equations to simulate the growth process of each type of volume were the equations of Richard,Gompertz and Richard in respectively.Each of the goodness of adjusted R-squared was more than 99%,which mean that they were suitable for tree growth prediction.（2）The optimal model of One-variable volume over bark and inside bark were V=0.000869D^1.954719andV=0.000922D^1.931255in respectively,the goodness of fitting accuracy was more than 99.9%.There was a significant linear correlation between root diameter and DBH.The optimal model of root diameter-volume over bark and inside bark wereV=0.000835D^1.863416andV=0.000777D^1.880267in respectively,the goodness of fitting accuracy was more than 99.8%.The related management tables prepared by the best individual tree growth model and volume model can provide basic data for estimate of forest resources.（3）There were significant differences in the biomass allocation ratios of primary branch,secondary branch and leaf at different branch diameters levels（2,4,6 and 8 cm）（P<0.05）.Majority live branch biomass occurred in the lower canopy layer,and was significantly higher than the upper layer（P<0.05）.The biomass allocation ratios of each organ were as follows:stem>root>branch>leaf.The biomass of organs at different DBH levels（14,18,22,26 and 30 cm as well as above）was significantly different（P<0.05）.The biomass allocation ratio of root was significantly different（P<0.05）,while the biomass allocation ratios of other organs were not significantly different（P>0.05）.（4）DBH and DBH-tree height ratio showed a extremely significant exponential correlation with tree competition intensity（P<0.01）,tree height-crown length ratio was showed a significantly index correlation with tree competition intensity（P<0.05）,while there was no significant correlation between tree height and tree competition intensity（P>0.05）.The biomass of stem,branch,leaf,root,tree crown and whole plant all showed a significantly exponential correlation with tree competition intensity（P<0.05）.（5）The precision values of the compatible biomass model system based on the nonlinear measurement error model for biomass of whole plant,aboveground,root,crown,stem,branch and leaf were 91.8%,91.0%,90.2%,85.1%,91.6%,86.8%and 71.0%,respectively.The model has a good fitting effect.