Global tree intrinsic water use efficiency is enhanced by increased atmospheric CO₂ and modulated by climate and plant functional types.

ABSTRACT: We conducted a meta-analysis of carbon and oxygen isotopes from tree ring chronologies representing 34 species across 10 biomes to better understand the environmental drivers and physiological mechanisms leading to historical changes in tree intrinsic water use efficiency (iWUE), or the ratio of net photosynthesis (A_net) to stomatal conductance (g_s), over the last century. We show a ∼40% increase in tree iWUE globally since 1901, coinciding with a ∼34% increase in atmospheric CO₂ (C_a), although mean iWUE, and the rates of increase, varied across biomes and leaf and wood functional types. While C_a was a dominant environmental driver of iWUE, the effects of increasing C_a were modulated either positively or negati

SUBMITTER: Mathias JM 

PROVIDER: S-EPMC7896309 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature