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Depth-dependency of trembling aspen and paper birch small-root responses to $eCO_{2}$ and $eO_{3}$

Journal Contribution - Journal Article

Projected changes in the atmospheric concentrations of CO2 and tropospheric O-3 over the next 50 years are of significant concern due to the linkages in the cycling of carbon and water in forested ecosystems. Responses of tree roots to elevated CO2 (eCO(2)) and O-3 (eO(3)) have been characterized primarily by studies of relatively shallow roots, yet deeper roots often play a disproportionately large role in water acquisition relative to their biomass. We undertook the present study to determine if there were significant root responses to eCO(2) and eO(3) below the maximum soil depths typically studied. In the current study, we characterized small root biomass and morphometric responses to eCO(2) and eO(3) at the Aspen-FACE Experiment in Rhinelander, Wisconsin down to a depth of one meter. Elevated CO2 caused relatively undifferentiated growth stimulation. Elevated O-3 stimulated root growth in the AA community at depth, while in the AB community there was a reduction in root growth in the shallow soil layer that was reversed in the deeper layers. Root responses below depths typically studied were qualitatively similar than those within shallower soils for eCO(2), but were sometimes compensatory for eO(3).
Journal: Plant and soil
ISSN: 0032-079X
Volume: 355
Pages: 215 - 229
Publication year:2012
Authors:International