Yan Mengjie, Mao Fangjie, Du Huaqiang, Li Xuejian, Chen Qi, Ni Chi, Huang Zihao, Xu Yanxin, Gong Yulin, Guo Keruo, Sun Jiaqian, Xu Cenheng
State Key Laboratory of Subtropical Silviculture, Zhejiang Agricultural & Forestry (A & F) University, Hangzhou, China.
Key Laboratory of Carbon Cycling in Forest Ecosystems and Carbon Sequestration of Zhejiang Province, Zhejiang A & F University, Hangzhou, China.
Front Plant Sci. 2023 Jan 17;14:1067552. doi: 10.3389/fpls.2023.1067552. eCollection 2023.
Subtropical forests are rich in vegetation and have high photosynthetic capacity. China is an important area for the distribution of subtropical forests, evergreen broadleaf forests (EBFs) and evergreen needleleaf forests (ENFs) are two typical vegetation types in subtropical China. Forest carbon storage is an important indicator for measuring the basic characteristics of forest ecosystems and is of great significance for maintaining the global carbon balance. Drought can affect forest activity and may even lead to forest death and the stability characteristics of different forest ecosystems varied after drought events. Therefore, this study used meteorological data to simulate the standardized precipitation evapotranspiration index (SPEI) and the Biome-BGC model to simulate two types of forest carbon storage to quantify the resistance and resilience of EBF and ENF to drought in the subtropical region of China. The results show that: 1) from 1952 to 2019, the interannual drought in subtropical China showed an increasing trend, with five extreme droughts recorded, of which 2011 was the most severe one; 2) the simulated average carbon storage of the EBF and ENF during 1985-2019 were 130.58 t·hm and 78.49 t·hm, respectively. The regions with higher carbon storage of EBF were mainly concentrated in central and southeastern subtropics, where those of ENF mainly distributed in the western subtropic; 3) The median of resistance of EBF was three times higher than that of ENF, indicating the EBF have stronger resistance to extreme drought than ENF. Moreover, the resilience of two typical forest to 2011 extreme drought and the continuous drought events during 2009 - 2011 were similar. The results provided a scientific basis for the response of subtropical forests to drought, and indicating that improve stand quality or expand the plantation of EBF may enhance the resistance to drought in subtropical China, which provided certain reference for forest protection and management under the increasing frequency of drought events in the future.
亚热带森林植被丰富，光合能力强。中国是亚热带森林分布的重要区域，常绿阔叶林（EBF）和常绿针叶林（ENF）是中国亚热带地区两种典型的植被类型。森林碳储量是衡量森林生态系统基本特征的重要指标，对维持全球碳平衡具有重要意义。干旱会影响森林活动，甚至可能导致森林死亡，干旱事件后不同森林生态系统的稳定性特征会有所不同。因此，本研究利用气象数据模拟标准化降水蒸散指数（SPEI），并采用生物群系-生物地球化学模型（Biome-BGC）模拟两种森林的碳储量，以量化中国亚热带地区常绿阔叶林和常绿针叶林对干旱的抗性和恢复力。结果表明：1）1952年至2019年，中国亚热带地区的年际干旱呈增加趋势，记录到5次极端干旱，其中2011年最为严重；2）1985年至2019年期间，模拟的常绿阔叶林和常绿针叶林平均碳储量分别为130.58 t·hm和78.49 t·hm。常绿阔叶林碳储量较高的区域主要集中在亚热带中部和东南部，常绿针叶林的碳储量主要分布在亚热带西部；3）常绿阔叶林的抗性中位数是常绿针叶林的3倍，表明常绿阔叶林对极端干旱的抗性比常绿针叶林更强。此外，两种典型森林对2011年极端干旱和2009 - 2011年持续干旱事件的恢复力相似。研究结果为亚热带森林对干旱的响应提供了科学依据，表明提高林分质量或扩大常绿阔叶林种植可能增强中国亚热带地区对干旱的抗性，为未来干旱事件频发下的森林保护和管理提供了一定参考。
