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Thawing permafrost can mitigate warming-induced drought stress in boreal forest trees.

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Kirdyanov, Alexander V 
Saurer, Matthias 
Arzac, Alberto 
Knorre, Anastasia A 
Prokushkin, Anatoly S 

Abstract

Perennially frozen soil, also known as permafrost, is important for the functioning and productivity of most of the boreal forest, the world's largest terrestrial biome. A better understanding of complex vegetation-permafrost interrelationships is needed to predict changes in local- to large-scale carbon, nutrient, and water cycle dynamics under future global warming. Here, we analyze tree-ring width and tree-ring stable isotope (C and O) measurements of Gmelin larch (Larix gmelinii (Rupr.) Rupr.) from six permafrost sites in the northern taiga of central Siberia. Our multi-parameter approach shows that changes in tree growth were predominantly controlled by the air and topsoil temperature and moisture content of the active soil and upper permafrost layers. The observed patterns range from strong growth limitations by early summer temperatures at higher elevations to significant growth controls by precipitation at warmer and well-drained lower-elevation sites. Enhanced radial tree growth is mainly found at sites with fast thawing upper mineral soil layers, and the comparison of tree-ring isotopes over five-year periods with different amounts of summer precipitation indicates that trees can prevent drought stress by accessing water from melted snow and seasonally frozen soil. Identifying the active soil and upper permafrost layers as central water resources for boreal tree growth during dry summers demonstrates the complexity of ecosystem responses to climatic changes.

Description

Keywords

Active soil layer, Boreal forest, Dendrochronology, Global warming, Siberia, Stable isotopes, Tree growth, Permafrost, Taiga, Ecosystem, Droughts, Soil, Forests

Journal Title

Sci Total Environ

Conference Name

Journal ISSN

0048-9697
1879-1026

Volume Title

Publisher

Elsevier BV
Sponsorship
This work was supported by the Russian Science Foundation (RSF), grant number 22-14-00048. Equipment purchased under the projects of the Ministry of Education and Science of the Russian Federation FSRZ-2023-0007 and FSRZ-2020-0014 was used for wood sample preparation. U.B. received funding from the Czech Science Foundation grant HYDRO8 (23-08049S), and the ERC Advanced grant MONOSTAR (AdG 882727).