Application of Rank-Sum Test in Checking the Effects of Thinning on the Growth of Plantation

The rank-sum test is an important non-parametric statistical method.The growth percentage of basal area and volume of 16 Larix olgensis plots with different thinning densities in Wang Qing Forestry Bureau was calculated.The rank-sum test was used to analyze the effects of thinning on stand growth and compare it with the analysis of variance used in parametric statistical method.The result showed that the rank-sum test could replace analysis of variance,furthermore,calculating was simpleness and convenience.