Related Experiment Video
Updated: Sep 30, 2026

A Simple Planting Technique for Re-establishing Trees Where Frequent Inundation Occurs
Published on: January 26, 2018
North America's oldest boreal trees are more efficient water users due to increased [CO2], but do not grow faster
Claudie Giguère-Croteau1,2,3, Étienne Boucher4,5,6, Yves Bergeron1,3,7
1Department of Biology, Université du Québec à Montréal, Montréal, QC H2X 1Y4, Canada.
Abstract:
Due to anthropogenic emissions and changes in land use, trees are now exposed to atmospheric levels of [[Formula: see text]] that are unprecedented for 650,000 y [Lüthi et al. (2008) Nature 453:379-382] (thousands of tree generations). Trees are expected to acclimate by modulating leaf-gas exchanges and alter water use efficiency which may result in forest productivity changes. Here, we present evidence of one of the strongest, nonlinear, and unequivocal postindustrial increases in intrinsic water use efficiency ([Formula: see text]) ever documented (+59%). A dual-isotope tree-ring analysis ([Formula: see text] and [Formula: see text]) covering 715 y of growth of North America's oldest boreal trees (Thuja occidentalis L.) revealed an unprecedented increase in [Formula: see text] that was directly linked to elevated assimilation rates of [Formula: see text] (A). However, limited nutrient availability, changes in carbon allocation strategies, and changes in stomatal density may have offset stem growth benefits awarded by the increased [Formula: see text] Our results demonstrate that even in scenarios where a positive [Formula: see text] fertilization effect is observed, other mechanisms may prevent trees from assimilating and storing supplementary anthropogenic emissions as above-ground biomass. In such cases, the sink capacity of forests in response to changing atmospheric conditions might be overestimated.
Related Concept Videos
C4 Pathway and CAM
C4 Pathway
The C4 pathway is used by plants such as...
Threats to Biodiversity
Meristems and Plant Growth
Adaptations that Reduce Water Loss
Responses to Drought and Flooding
Softwoods and Hardwoods

