Primary study of diameter effect on the ability of stump sprouting of Lebanon oak (Quercus libani Oliv.) in northern Zagros forests (case study: Armardeh, Baneh)

This study was carried out in order to compare the number of produced sprouts in Lebanon oak (Quercus libani Oliv.) tree after cutting among dbh classes in northern Zagros forests. 3 dbh classes including 25-35, 35-45 and >45 cm were compared in respect of number of produced sprouts. 5 sites in Armardeh forests were selected and results of study analyzed by random complete block design. 3 Lebanon oak trees were cut in each diameter class and in each block. The 45 cut trees were fenced in early spring 2007 individually. Data were collected two times in June and September. Results showed that 35-45 cm dbh class had the most number of sprouts (with 101 and 81 sprouts in June and September, respectively). Number of sprouts in 35-45 cm dbh class was significantly different from others in September, while no significant difference was found in number of sprouts between June and September. Mortality rate of sprout among dbh classes was not significantly different. However, linear regression trend between number of June sprout and died sprouts until September showed that mortality increased when number of June sprout increased. Since sprouting depend on positive and negative effects of stump size, balance point of these effects was introduced as optimum diameter for sprouting, which was between 35-45 cm dbh range in this study. Future investigations should be focused on finding the balance point (or range), more precisely.