Contrasting water-use strategies to climate warming in white birch and larch in a boreal permafrost region.

• Published in: Tree Physiology
• Main Authors: Qi, Xi, Treydte, Kerstin, Saurer, Matthias, Fang, Keyan, An, Wenling, Lehmann, Marco, Liu, Kunyuan, Wu, Zhengfang, He, Hong S, Du, Haibo, Li, Mai-He
• Format: Article in Journal/Newspaper
• Language: English
• Published: Silverchair Information Systems 2024
• Subjects: climate change; intrinsic water-use efficiency; permafrost forest; radial growth; tree-ring isotopes; permafrost
• Online Access: https://doi.org/10.1093/treephys/tpae053; https://pubmed.ncbi.nlm.nih.gov/38769900

The effects of rising atmospheric CO2 concentrations (Ca) with climate warming on intrinsic water-use efficiency and radial growth in boreal forests are still poorly understood. We measured tree-ring cellulose δ13C, δ18O, and tree-ring width in Larix dahurica (larch) and Betula platyphylla (white birch), and analyzed their relationships with climate variables in a boreal permafrost region of northeast China over past 68 years covering a pre-warming period (1951-1984; base period) and a warm period (1985-2018; warm period). We found that white birch but not larch significantly increased their radial growth over the warm period. The increased intrinsic water-use efficiency in both species was mainly driven by elevated Ca but not climate warming. White birch but not larch showed significantly positive correlations between tree-ring δ13C, δ18O and summer maximum temperature as well as vapor pressure deficit in the warm period, suggesting a strong stomatal response in the broad-leaved birch to temperature changes. The climate warming-induced radial growth enhancement in white birch is primarily associated with a conservative water-use strategy. In contrast, larch exhibits a profligate water-use strategy. It implies an advantage for white birch over larch in the warming permafrost regions.