Methods for dividing the spatial structural units of oak secondary forest under self-thinning condition
[Objective]The division of self-thinning structural units of oak secondary forest is the basis of applying the law of self-thinning of forest to carry out the management of oak secondary forest.[Method]Based on the data of forest resources continuous inventory in 2009 and 2014 in Hunan province,6 oak secondary forest plots were used as data sources,three methods of spatial structure unit division were used to obtain several structural units,and the plant number density and average DBH of trees in each structural unit were calculated to establish the Reineke density index model.The fitting effect and testing effect of the model were compared.[Result]The self-thinning boundary lines R² fitted by the samples obtained by methods 1,2 and 3 were 0.882,0.780 and 0.893,respectively.RMSE were 0.180,0.229 and 0.169,respectively.Method 3 had the best fitting effect.Among the verification results of the three methods,the correct rate of method 3 was 72%,and the verification effect was the best.The other two methods were below 50%.[Conclusion]Among the three structural unit division methods,method 1 ignored the sample wood far away from the dead wood;Method 2 did not consider the difference of the effects of different locations of sample trees on dead trees;Method 3(Voronoi diagram+sample circle weight method)more completely counted the sample trees that had influence on self-thinning,and divided them into Class I and Class II samples,calculated the weights respectively,and analyzed the difference of their influence on dead trees.It is a division method of stand spatial structure unit,which considers the difference of spatial distribution of trees and distinguishes the types of sample trees according to the influence of dead trees.
oak secondary forestself-thinningstand spatial structural unitHunan province
NETL
NSTL
万方数据
