Experimental vs. Modeled Water Use in Mature Norway Spruce (Picea abies) Exposed to Elevated CO₂
Date
Authors
Supervisor
Item type
Journal Article
Degree name
Journal Title
Journal ISSN
Volume Title
Publisher
Frontiers Media
Abstract
Rising levels of atmospheric CO₂ have often been reported to reduce plant water use. Such behavior is also predicted by standard equations relating photosynthesis, stomatal conductance, and atmospheric CO₂ concentration, which form the core of dynamic global vegetation models (DGVMs). Here, we provide first results from a free air CO₂ enrichment (FACE) experiment with naturally growing, mature (35 m) Picea abies (L.) (Norway spruce) and compare them to simulations by the DGVM LPJ-GUESS. We monitored sap flow, stem water deficit, stomatal conductance, leaf water potential, and soil moisture in five 35-40 m tall CO₂-treated (550 ppm) trees over two seasons. Using LPJ-GUESS, we simulated this experiment using climate data from a nearby weather station. While the model predicted a stable reduction of transpiration of between 9% and 18% (at concentrations of 550-700 ppm atmospheric CO₂), the combined evidence from various methods characterizing water use in our experimental trees suggest no changes in response to future CO₂ concentrations. The discrepancy between the modeled and the experimental results may be a scaling issue: while dynamic vegetation models correctly predict leaf-level responses, they may not sufficiently account for the processes involved at the canopy and ecosystem scale, which could offset the first-order stomatal response.Description
Keywords
Science & Technology, Life Sciences & Biomedicine, Plant Sciences, dendrometer, DGVM, FACE, leaf water potential, sap flow, stomatal conductance, vegetation modeling, Deciduous Forest Trees, Vapor-Pressure Deficit, Aspen-Birch Forests, Carbon-dioxide, Atmospheric CO₂, Use efficiency, Sap flux, Canopy conductance, Rising CO₂, 3108 Plant Biology, 31 Biological Sciences, 3103 Ecology, 13 Climate Action, 0607 Plant Biology, 3004 Crop and pasture production, 3108 Plant biology
Source
Frontiers in Plant Science, ISSN: 1664-462X (Print); 1664-462X (Online), Frontiers Media, 3(OCT), 229-. doi: 10.3389/fpls.2012.00229
Rights statement
Copyright © 2012 Leuzinger and Bader. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.