Reveals the mechanism of the inter-annual variation of carbon sequestration in subtropical forests

Date： Jul 22, 2021 | Size: 【 A A A 】 | 【Print】 | 【Close】

Carbon sequestration in subtropical forests is an important way to achieve the double carbon goals of "emission peak" and "carbon neutrality" in China. However, carbon sequestration in subtropical forests changes greatly from year to year, making it difficult for accurate simulation and prediction, especially under the background of frequent extreme climate events caused by global change.

Therefore, LI Xueyan from the Ecology & Environment Science Center, under the supervision of PI Dr. Wang and Dr. Yan, investigated the influence mechanism of climate extremes using land surface model CABLE based on long-term flux observation data and forest community survey data. Model simulation of the interannual variation carbon cycle of the Dinghu subtropical coniferous and broad-leaved mixed forest shows that the snow and ice disaster in 2008 and the continuous drought from 2011 to 2013 significantly reduced the carbon sequestration capacity of the forest and even turned it into a carbon source, which was mainly due to the different responses of total primary productivity (GPP) and ecosystem respiration (TER) to extreme weather events. The modeled maximum leaf carboxylation rate (Vcmax) was reduced to capture the observed reduction in GPP during extreme years.

Parameter optimization suggests that the reduced Vcmax recovered rapidly after hot and cold spells but remained at a low level after continuous drought. Extreme climate events resulted in a significant increase in tree mortality and litterfall, which caused TER increment in the following year. Our results reveal that the dynamic change of VCmax and the TER lag effect caused by extreme climate events are important factors in regulating the interannual variation of subtropical forest carbon sequestration.

This study has been published in Agricultural and Forest Meteorology. For more details please see https://authors.elsevier.com/sd/article/S0168-1923(21)00191-X

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