Impacts of the Wenchuan earthquake on tree mortality and biomass carbon stock

The Wenchuan earthquake caused tremendous damages to forests, which could increase tree mortality, disrupt forest carbon cycling, and pose serious challenge to sustainable forest management. In this study, we analyzed data from 871 permanent forest plots from the Sichuan forest inventory (SFI) system to quantify the impacts of 2008 Wenchuan earthquake on tree mortality and forest biomass carbon. Our results showed that the 5-year tree mortality had significantly increased from 2.26 to 3.52 % in the region with seismic intensity of ≥VII (VII and above), and even more dramatically in the hardest hit zone with seismic intensity of X and XI, which showed an increase from 3.77 to 8.96 %. It is estimated that the Wenchuan earthquake had killed as much as 34.5 million trees and mobilized a dead carbon pool of 1050 Gg C (7.87 Mg C/km²/a) in the region with seismic intensity of ≥VII. Our results suggested that the earthquake was the main cause of this risen tree mortality and the loss of huge amount of forest biomass carbon. This study demonstrated that tree mortality derived from forest plots can be used to estimate disaster-induced forest carbon loss for the purpose of hazard assessment.