Nonparametric Analysis of Plot Basal Area Growth Using Tree Based Models

摘要

The authors used nonparametric and nonlinear models to reexamine the data sets ontree growth used by Bechtold et al. (1991) and Ruark et al. (1991). The authors used tree based models to group observations into clusters that were specified by covariate values. Next, the authors performed a permutation test on the grouped data to test for a change in tree growth rates from the 4th cycle to the 5th cycle. The authors' techniques differed from those used by Bechtold et al. (1991) and Ruark et al. (1991). The methodology presented is general and applicable to other situations where the significance of a specific covariate is in question. Despite these relaxed constraints of analysis, the authors' results generally agreed with those of Bechtold et al. and Ruark et al.