In this study, the effects of the leaf area (l.a) and leaf area index (l.a.i) values on diameter, height and weight increments for various forest tree seedlings in Cankiri Kenbag forest nursery was investigated. 30 seedlings of 3 tree species which are downy oak (DO) (2+0) (Quercus pubescens Willd.), common ash (CA) (2+0) (Fraxinus excelsior L.) and boxelder (B) (2+0) (Acer negundo L.) were examined. The volume parameters of the seedlings [diameter (mm), height (cm), leaf area (mm(2)), stem and leaf weights (g)] were measured. ANOVA and Tukey's multiple comparison tests were used in order to determine the different groups with regard to volume and volume parameters. According to the results, there were significant differences between B and CA with regard to lead area index and diameter and height increment, between CA and DO with regard to leaf area index and height increment. A significant difference has been found between B and DO and between CA and DO with regard to volume increment in individual leaf area. Also, another significant difference between semi-shade tolerant and light demanding tree species with regard to the volume increment effect of the leaf area (1 m(2)).