Architectural model and impact of root pruning on diameter and height growth of Oak (Quercus castaneifolia) seedlings (Pilambara_Guilan)

25 seedlings of Caucasian oak (Quercus castaneifolia) were planted by spacing of 1*1m in Pilambra research station, Guilan province, north of Iran. Prior to transplanting, seedlings were root-pruned in three levels of 15, 20 and 25 cm and some of quantitative characteristics of plants were compared to those of un-pruned controls in 3 replications after six growing seasons. A total of 300 seedlings in completely randomized blocks were studied. Considering the criteria of rhythmic shoot extension, branching mode and orthotropic branch differentiation the architectural model of the Caucasian oak was identified as Rauh model. The results showed that root pruning has a significance influence on diameter and height growth of oak seedlings. The collar diameter, dbh and height of seedlings were 60.5mm, 40.5mm and 616.3cm, respectively which were the highest measurements among the treatment of root pruning in 20cm. The un-pruned seedlings showed better results than those of pruned in 15cm and 25cm. All differences were significant at level of p<0.05.