Effects of freeze damage on litter production, quality and decomposition in a loblolly pine forest in central China

Freeze events can strongly influence many ecosystem processes. However, the effects of freeze events on litter production, litter quality, and decomposition are rarely documented. In this study, litter fall was measured monthly for 2 years. Two litter decomposition experiments were also performed using freeze-damaged litter and non-damaged litter in a loblolly pine forest. The freeze event in November 2009 caused a pronounced pulse of needle litter fall. The freeze-damaged needle litter was shown to have higher N concentration and lower C/N ratio compared with the normal falling needle litter. This finding indicates that freeze damage significantly increased needle quality because of incomplete nutrient resorption. The decomposition of freeze-damaged needle litter was faster than that of normal falling yellow needle litter and slower than that of hand-picked green needle litter. The decomposition rate constant (k) was negatively correlated with the C/N ratio in the needle litter. Our results also showed that the different climatic conditions influence patterns of litter decomposition. This study suggests that freeze events significantly alter litter quantity and quality, thus affecting litter decomposition rates in a loblolly pine forest in central China.