Technical Note: Linking climate change and downed woody debris decomposition across forests of the eastern United States

[摘要] Forest ecosystems play a critical role in mitigating greenhouse gasemissions. Forest carbon (C) is stored through photosynthesis and releasedvia decomposition and combustion. Relative to C fixation in biomass, muchless is known about C depletion through decomposition of woody debris,particularly under a changing climate. It is assumed that the increasedtemperatures and longer growing seasons associated with projected climatechange will increase the decomposition rates (i.e., more rapid C cycling) ofdowned woody debris (DWD); however, the magnitude of this increase has notbeen previously addressed. Using DWD measurements collected from a nationalforest inventory of the eastern United States, we show that the residencetime of DWD may decrease (i.e., more rapid decomposition) by as much as13% over the next 200 years, depending on various future climate changescenarios and forest types. Although existing dynamic global vegetationmodels account for the decomposition process, they typically do not includethe effect of a changing climate on DWD decomposition rates. We expect thatan increased understanding of decomposition rates, as presented in thiscurrent work, will be needed to adequately quantify the fate of woodydetritus in future forests. Furthermore, we hope these results will lead toimproved models that incorporate climate change scenarios for depictingfuture dead wood dynamics in addition to a traditional emphasis on live-treedemographics.

[学科分类] 地球化学与岩石