Effect of canopy density on natural regeneration in Manesht oak forests of Ilam

In order to study the effect of canopy and stand density on natural regeneration, 460 ha from oak forests of southern aspect of Manesht mountain in north of Ilam province was selected. Forty six sample plots, each 2000 m² for recording stands characteristics and 46 micro plots, each 400 m² for recording regeneration characteristics were established by random systematic sampling method. Variables in macro-plots included dbh, maximum and minimum crown diameter of all tree species. Number, height and quality of seedlings were studied in the micro-plots. The collected data were analyzed by Excel and Spss softwares (ANOVA test) and then compared using of Dancan test and correlation. Results showed that the abundance of seedlings in this area were low. The number of Quercus brantii and Pistacia atlantica seedlings has a positive correlation with canopy density, whereas Lonicera nummularifolia and Amygdalus orientalis had negative correlation. The maximum height of Quercus brantii seedlings (160 cm) found in denser canopy, while it was 88 cm in stands with open canopy. The maximum seedling height (154 cm) of Lonicera nummularifolia and Amygdalus orientalis were measured in the stands with open canopy. The mean height of seedling, the ratio of tall seedlings to whole seedlings and their vitality in denser canopy (located in northern aspect and medium elevation) were more than those in the stands with open canopy (located in southern aspect and higher elevation). These results indicate the best growth condition in northern aspect and medium elevation due to the richer canopy.