Fig. 2

Comparison of the variables in all study plots and field surveys for different site index (SI) and stand age classes; (a) mean mortality rate, (b) basal area of trees larger than the subject tree (BAL), (c) diameter at breast height (DBH). SI classes were defined as high (SI > 25), middle (20 < SI < 25), and low (SI < 20). Age classes were defined as older (age > 50), mature (30 < age < 50), and young (age < 30). The error bar indicates standard error. **** indicates a significant difference (t-test, p < 0.001). The error bar indicates the standard deviation