Long-lasting legacy of forest succession and forest management: Characteristics of coarse woody debris in an evergreen broad-leaved forest of Eastern China

Coarse woody debris (CWD) is an important structural and functional component in evergreen broad-leaved forests in Eastern China. In this study, we determine the temporal patterns of CWD in Tiantong National Forest Park by examining the CWD volume and mass in different decay classes and size classes along a chronosequence of secondary forest succession. The volume and mass of CWD followed the general “U-shaped” temporal trend: highest in the late-successional forest (97.73 m3/ha, 42.41 Mg/ha), lowest in the middle successional forest (6.13 m3/ha, 2.84 Mg/ha) and intermediate in the early successional forest (46.12 m3/ha, 19.36 Mg/ha). The late-successional forest had larger amount of logs and stumps than the other two forests. In contrast, snags biomass and volume did not differ among these three forests. CWD in decay classes III and V was greater in late-successional forest than that in the other two forests, while CWD in decay classes II and IV did not differ among the three successional forests. CWD in class 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 Pinus massoniana and followed by Schima superba. In the late-successional forest, CWD in early decay class was dominated by Castanopsis fargesii while CWD in late decay class was dominated by P. massoniana and S. superba. While forest succession had a large influence on the amount of CWD in different decay class, it had no effect on CWD distribution among different size classes. Our results suggested that both anthropogenic and natural disturbances have left a long-lasting legacy on the distribution of CWD among three forests.