Temperature sensitivity of plant litter decomposition rate in China's forests

Abstract

Abstract The decomposition of litter from forest tree species is a fundamental process in the carbon (C) cycle of terrestrial ecosystems and is closely related to ongoing climate change. However, the spatial distribution of the forest litter decomposition rate (k) and its potential response to changing air temperature (temperature sensitivity) remain poorly understood. Here, we estimated the spatial pattern of forest plant k values in China by performing a random forest model based on 433 standardized k values from 124 published studies. Nine potential predictors, including climate‐related factors, vegetation characteristics, and soil physical and chemical factors, were considered in the model. The results of spatial extrapolation indicated that the average k value for China's forests was 0.53, and the mean annual temperature (MAT) was the most important factor. We also mapped the spatial pattern of the temperature sensitivity of the k value (Q10) by using a moving window method. We found that the Q10 values had considerable variation (from 0.05 to 11.68, 95% confidence interval, CI) across forest types and regions. The Q10 values were lower in the warmer regions (primarily in the sub‐tropical evergreen forests) and higher in the semi‐humid regions (primarily in the temperate deciduous forests and boreal Larix forests) than those in the other regions of China. However, the Q10 values of the broadleaved forests were higher than those of coniferous forests. These results suggest that the temperature sensitivity of the litter decomposition rate will decline under the ongoing global warming. Changing patterns of precipitation will also affect not only the forest litter decomposition rate but also its temperature sensitivity.

Keywords

• climate
• litter decomposition rate
• Q 10
• spatial pattern