Carbon Storage And Respiration Of Coarse Woody Debris In Evergreen Broad-leaved Forest In Wanmulin Natural Reserve

This study has focused on the coarse woody debris (CWD) in mid-subtropical evergreen broad-leaved forest in Wanmulin Natural Reserve of Fujian province, China. The storage, carbon pool and its composition of CWD were investigated. Infrared gas analysis (IRGA method, LI-8100 Automated Soil CO2 Flux System) was used to measure log respiration flux and its seasonal changes. We wanted to reveal how environmental factors (mainly temperature and water content) and decay class influence the log respiration. The results showed that the total storage of CWD was 23.18 t·hm"2 and the total carbon storage of CWD was 10.31 t-hm"2, while the major components of CWD were downed logs. The observed respiration of logs indicated that log respiration rates of four decay classes showed obvious seasonal variation, and the maximum rates were in June or July and the minimum rates in January. Respiration of logs were significantly positively correlated with temperature of logs, and the temperature of logs could explain the seasonal changes of logs respiration to a large extent (45.8%～79.62%). The range of Q10 values of log respiration in four decay classes which can reflect the sensitivity of respiration to temperature changes were 1.78～2.88. The correlation in respiration and water content was not significant. There was obvious difference in log respiration among different decay classes. The estimated annual efflux of downed logs in mid-subtropical evergreen broad-leaved forest in Wanmulin was 95.05 g C·m-2-a-1. The annual carbon flux of logs respiration accounted for 5.8% of annual soil respiration in these sites. These studies showed that respiration flux of logs were important components which can not be ignored in these sites. This study can provide available data for preparation of greenhouse gas inventories and construction of forest carbon cycle models. There was great significance for deeply understanding forest carbon cycle mechanisms and their response to global change and accurately assessing the role of forests in carbon exchange.