Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí lâm nghiệp đề tài: Characteristics of coarse woody debris in successional stages of natural beech (Fagus orientalis) forests of Northern Iran. | JOURNAL OF FOREST SCIENCE 56 2010 1 7-17 Characteristics of coarse woody debris in successional stages of natural beech Fagus orientalis forests of Northern Iran K. Sefidi M. R. Marvie Mohadjer Department of Forestry Faculty of Natural Resources University of Tehran Karaj Iran ABSTRACT Coarse woody debris CWD is an important structural and functional component in forests in Northern Iran. In this study we determine the temporal patterns of CWD in Kheyroud Forests by examining the CWD volume in different decay classes and size classes along a chronosequence of secondary forest succession. The volume of CWD followed the general U-shaped temporal trend the highest in the late successional forest lowest in the middle successional forest and intermediate in the early successional forest . The late successional forest had a larger amount of logs snags and stumps than the other two forests. In contrast the snag volume did not differ between the late and middle successional forest. CWD in decay classes III and V was greater in the late successional forest than that in the other two forests while CWD in decay classes II and I did not differ among the three successional forests. CWD in class II and I was significantly higher in the early successional forest than that in the middle successional forest. In the early and middle successional forests CWD in early decay class was dominated by Carpinus betulus L followed by Fagus orientalis Lipsky. In the late successional forest CWD in early decay class was dominated by Fagus orientalis while CWD in the late decay class was dominated by Carpinus betulus. While forest succession had a large influence on the amount of CWD in different decay classes it had no effect on CWD distribution among the different size classes. Our results suggest that both anthropogenic and natural disturbances have had a long-term effect on the distribution of CWD among three forests. Keywords coarse woody debris .