Decoupling of tree height and root depth across the globe and the implications for tree mortality during drought events. (March 2023)

• Record Type: Journal Article
• Authors: Feng, Xiangyan; Zhao, Wenzhi; Yang, Qiyue; Zhou, Hai
• Is Part Of: Ecological indicators. Volume 147(2023)
• Publication Date: 2023-03
• Subjects: Functional traits -- Supply–demand balance -- Evolution -- Drought stress -- Ecological strategy; Environmental monitoring -- Periodicals; Environmental management -- Periodicals; Environmental impact analysis -- Periodicals; Environmental risk assessment -- Periodicals; Sustainable development -- Periodicals; 333.71405
• DOI: 10.1016/j.ecolind.2023.109944
• Languages: English
• ISSNs: 1470-160X

Abstract

Highlights: Tree height and root depth were often decoupled across the globe. Tree height and root depth were driven by climate drivers and evolutionary history. The trees with tall height but shallow roots accompanied with dense root structures. Trees with tall height but shallow roots facing great mortality risk during drought. Abstract: Tree height ( H tree ) and root depth ( D root ) are the two most critical functional traits for plant ecological strategies. However, the global varying patterns of H tree and D root and the ecological significance for tree survival under changed climate conditions are less understood. Here, we compiled H tree, D root, and six root traits related to soil resource absorption for 301 field-grown tree species distributed 776 sites worldwide. The relationships between H tree and D root across different climate conditions and the implications for tree mortality during drought events were investigated. We found H tree and D root were often decoupled in angiosperms and gymnosperms among different climate conditions. Greater H tree was prone to occur in warm and moist climates, while greater D root tended to occur in warm and dry climates with low soil water availability. Phylogenetic analysis revealed that trees have evolved towards smaller H tree but deeper D root from the deep time. Although dense root structures to some extent contributed to sustaining the resource supply–demand balance of large trees with shallow roots (great H tree / D root ), the large trees with greater H tree / D root were more vulnerable to drought-induced mortality. The findings suggest that the linkage of below- and above-ground reaches has a pivotal role in understanding tree mortality during drought events. The insight will allow more accurate vegetation model prediction for tree sorting processes under climate change scenarios.