文章基本信息

标题：Nonlinear Increase of Vegetation Carbon Storage in Aging Forests and Its Implications for Earth System Models
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作者：Chen Zhu ; Jianyang Xia
期刊名称：Journal of Advances in Modeling Earth Systems
电子版ISSN：1942-2466
出版年度：2020
卷号：12
期号：12
页码：307-323
DOI：10.1029/2020MS002304
出版社：John Wiley & Sons, Ltd.
摘要：Vegetation carbon stock (Cveg) in global forests, which is important for C cycle‐climate feedbacks, commonly increases with forest age. Due to the allometric growth of plants, the nonlinear increase in Cveg with woody fraction ( fw) is expected across space. However, it remains unclear whether such a nonlinear relationship between Cveg and fw can be constrained by observations and further used to benchmark Earth system models (ESMs). Here, based on the in situ measurements at 1,145 forest sites, we found that the nonlinear relationship between Cveg and fw followed an exponential equation (i.e., Cveg ¼ bea · f w ). Then, we showed that such an exponential dependence of Cveg on fw also exists in ESMs of CMIP5 and CMIP6 (all P 30°N) was not captured by ESMs. These findings reveal a high disagreement on the spatially nonlinear relationship between vegetation carbon stock and woody fraction in current ESMs. The exponential relationship based on observations provides one useful benchmark for ESMs when they implement the age‐dependent processes in the future.