NET PRIMARY PRODUCTIVITY OF A CO 2 -ENRICHED DECIDUOUS FOREST AND THE IMPLICATIONS FOR CARBON STORAGE
2002; Wiley; Volume: 12; Issue: 5 Linguagem: Inglês
10.1890/1051-0761(2002)012[1261
ISSN1939-5582
AutoresRichard J. Norby, Paul J. Hanson, Elizabeth G. O’Neill, Timothy J. Tschaplinski, Jake F. Weltzin, Randi A. Hansen, Weixin Cheng, Stan D. Wullschleger, Carla A. Gunderson, Nelson T. Edwards, Dale W. Johnson,
Tópico(s)Soil Carbon and Nitrogen Dynamics
ResumoA central question concerning the response of terrestrial ecosystems to a changing atmosphere is whether increased uptake of carbon in response to increasing atmospheric carbon dioxide concentration results in greater plant biomass and carbon storage or, alternatively, faster cycling of C through the ecosystem. Net primary productivity (NPP) of a closed-canopy Liquidambar styraciflua (sweetgum) forest stand was assessed for three years in a free-air CO2-enrichment (FACE) experiment. NPP increased 21% in stands exposed to elevated CO2, and there was no loss of response over time. Wood increment increased significantly during the first year of exposure, but subsequently most of the extra C was allocated to production of leaves and fine roots. These pools turn over more rapidly than wood, thereby reducing the potential of the forest stand to sequester additional C in response to atmospheric CO2 enrichment. Hence, while this experiment provides the first evidence that CO2 enrichment can increase productivity in a closed-canopy deciduous forest, the implications of this result must be tempered because the increase in productivity resulted in faster cycling of C through the system rather than increased C storage in wood. The fate of the additional C entering the soil system and the environmental interactions that influence allocation need further investigation.
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