| Title: | Defoliation-induced tree growth declines are jointly limited by carbon source and sink activities |
| Address: | "Center for Ecological Research, Northeast Forestry University, 26 Hexing Road, Harbin 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management - Ministry of Education, Northeast Forestry University, Harbin 150040, China. Center for Ecological Research, Northeast Forestry University, 26 Hexing Road, Harbin 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management - Ministry of Education, Northeast Forestry University, Harbin 150040, China. Electronic address: wangck@nefu.edu.cn" |
| DOI: | 10.1016/j.scitotenv.2020.143077 |
| ISSN/ISBN: | 1879-1026 (Electronic) 0048-9697 (Linking) |
| Abstract: | "Defoliation resulting from herbivory, storm, drought, and frost may seriously impair tree growth and forest production. However, a comprehensive evaluation of defoliation impacts on tree carbon (C) assimilation and growth has not been conducted. We performed a meta-analysis of a dataset that included 1562 observations of 40 tree species from 50 studies worldwide, and evaluated defoliation impacts on photosynthetic capacity, C allocation, and tree growth. Our results showed that the reduced tree-level leaf area by defoliation outweighed the enhanced leaf-level photosynthesis, leading to a net reduction in tree C assimilation that was accompanied with decreases in nonstructural carbohydrates (NSCs) concentrations. The negative effects of defoliation on leaf NSCs decreased over time, but leaf production increased following defoliation, suggesting a shift in the C allocation towards shoots over roots. Defoliation intensity negatively affected tree growth, but post-defoliated recovery time did oppositely. The structure equation modelling showed that defoliation reduced tree growth mainly by indirectly reducing C assimilation (r = -0.4), and minorly by direct negative effect of defoliation intensity (r = -0.28) and positive effect of post-defoliated time (r = 0.33). These findings suggest that tree growth declines caused by defoliation are co-limited by C-source and sink activities, which provide a physiological basis of tree growth that is of significance in tree growth modelling and forest management under global changes" |
| Keywords: | *Carbon Droughts Photosynthesis Plant Leaves *Trees Carbon allocation Carbon sink Carbon source Carbon storage Defoliation Tree growth; |
| Notes: | "MedlineWang, Zhaoguo Zhou, Zhenghu Wang, Chuankuan eng Meta-Analysis Netherlands 2020/11/03 Sci Total Environ. 2021 Mar 25; 762:143077. doi: 10.1016/j.scitotenv.2020.143077. Epub 2020 Oct 17" |
