ARS | Publication request: CO2 FERTILIZATION: WHEN, WHERE, HOW MUCH?

Submitted to: Global Change and Terrestrial Ecosystems
Publication Type: Book / Chapter
Publication Acceptance Date: May 18, 2005
Publication Date: January 17, 2007
Citation: Korner, C., Morgan, J.A., Norby, R. 2007. CO2 fertilization: When, where, how much? pp 9-22. In: Canadell, J.G., Pataki, D.E., Pitelka, L.F. (eds), Terrestrial ecosystems in a changing world. The IGBP series. 336 pages. Springer, Berlin.

Technical Abstract: Experimental CO2 research with plants and whole ecosystems has made it clear that there is no straightforward relationship between the generally observed stimulation of leaf photosynthetic rates by elevated CO2 concentrations and growth or productivity. The large number of tests with a broad spectrum of species and growth conditions has made it obvious that the extent to which greater availability of carbon to plants will translate into more structural growth depends on nutrient availability, either directly or via soil moisture conditions. The realism of projections derived from experimental works thus depends on the realism of nutrient and water regimes provided during tests. For the vast majority of non-agricultural ecosystems it seems that resources other then CO2 control growth and productivity to such an extent that CO2 concentrations above current levels exert little or no long-term stimulation. The major influence of atmospheric CO2 on biota comes in (1) via differential responses of plant taxa or plant functional groups,(2) effects on water relations, and (3) soil feed back induced by greater C- input, the latter least understood. This brief review of some of the salient findings in CO2 enrichment research in grassland and forest systems points to these and other limitations of our present knowledge of ecosystem responses to CO2, and suggests new avenues and partnerships in global change research that may effectively tap critical resources for establishing more effective investigations into the consequences of global change on forest systems.