Keywords: 
• forest mensuration /
• diameter class diversity /
• diversity indices /
• discriminant ability /
• sample size /
• Changbai Mountains

Abstract: Diameter class diversity，as an important part of structural diversity within a stand，affects the economic，ecological，and social value of forests. The objective of this paper is to evaluate different diameter indices describing diameter class diversity based on discriminant ability and sensitivity to sample size. Seven commonly used diversity indices：the Margalef index，Shannon index，Gini coefficient，Simpson index，Berger-parker index，Pielou evenness and Shannon evenness were calculated for 4 spruce-fir conifer and broadleaf mixed stands with different cutting intensities（0，20%，30%，40%） during 7 investigating time（1986，1990，1993，1997，2001，2005，2009） in the Changbai Mountains. Then，the discriminant ability and sensitivity for sample sizes of different diversity indices were evaluated. Results showed that with respect to discriminant ability the Margalef index，Shannon index，and Gini coefficient were superior，but the Gini coefficient was best as the Margalef and Shannon indices were sensitive to sample size. Based on different cutting intensities，variation in the index values before and after cutting showed that diameter diversity increased when the cutting intensity was between 20% and 30%，and decreased when the cutting intensity was 40%. A wide range of applications for diameter diversity indices in forest management include comparing diameter diversity in different stands，assessing changes in tree size diversity over time in stands or on a landscape level，and evaluating the effects of different management treatments on diameter diversity in stands. ［Ch，6 tab. 18 ref.］