Abstract:

This study takes the distance structure of the natural Haloxylon ammodendron stand as the research object.Through the construction of the nearest neighbor distance probability distribution model of the Haloxylon ammodendron stand,an estimated distance model independent of the tree species will be established,which will support the analysis of the spatial structure of different tree species in the forestry investigations.In this study,we use Matlab to generate three simulated plots of uniform,random and mass distribution types,and fit the nearest neighbor distance distribution model for the target points in the simulated plots and the stands of the measured plots.Through the Kolmogorov-Smirnov(K-S) test of the model fitting parameters,the results show that the simulation sample is simulated.The nearest neighbor distribution of ground and measured plots can be fitted with the Weibull distribution(Weibull-2) model with sound fitting eflects,in which the R² value of simulated and measured plots is between 0.8832 to 0.9966 and the mean square root error(RMSE) is between 0.0034 to 0.0516 and 0.0066 to 0.0414.The value of D is less than the D_0.05 value as the result meets the original hypothesis.Therefore,the Weibull-2 distribution model can be used to describe the distribution of the distance structure of the natural Haloxylon ammodendron,which shows good adaptability.It shows that the Weibull-2 distribution model can be used to describe the spatial structure of the stand of different tree species.

Key words: Haloxylon ammodendron, Weibull distribution model, nearest neighbor distance, distance structure