资源环境科技发展态势分析平台

Enhanced solar radiation (induced photodegradation) is an important driver of global environmental change. Coarse woody debris (CWD) plays a key role in forest carbon (C) dynamics because it contains a sizeable proportion of total forest C. Therefore, understanding the effects and underlying mechanisms of photodegradation on CWD decomposition is critical for the assessment of C storage in forests.

We conducted a field-based experiment to investigate the effects of photodegradation on the respiration of CWD (R-CWD) of Cunninghamia lanceolata (CL), Schima superba (SS), and Cinnamomum caniphora (CC) over a 24 month period in subtropical China. And we also determined the effects of changes in CWD temperature and moisture content on R-CWD of the three tree species. We found that photodegradation significantly accelerated R-CWD, with its effect further amplified by increasing temperature. The temperature sensitivities of R-CWD to CWD temperature as indicated by Q(10) were increased by photodegradation treatments. The CWD temperature can explain over 70% of the variation in R-CWD among different tree species and treatments. Our results indicate that the positive effect of photodegradation on CWD decomposition and C cycles could potentially impact C cycling in forest ecosystems. These findings may provide insight on the effects of photodegradation and temperature change on biogeochemical cycling of forest ecosystems under the future global change.