Changes in biomass allocation buffer low CO2 effects on tree growth during the last glaciation

Li, G., Gerhart, L. M., Harrison, S. P. ORCID: https://orcid.org/0000-0001-5687-1903, Ward, J. K., Harris, J. M. and Prentice, I. C. (2017) Changes in biomass allocation buffer low CO2 effects on tree growth during the last glaciation. Scientific Reports, 7. 43087. ISSN 2045-2322 doi: 10.1038/srep43087

Abstract/Summary

Isotopic measurements on junipers growing in southern California during the last glacial, when the ambient atmospheric [CO2] (ca) was ~180 ppm, show the leaf-internal [CO2] (ci) was approaching the modern CO2 compensation point for C3 plants. Despite this, stem growth rates were similar to today. Using a coupled light-use efficiency and tree growth model, we show that it is possible to maintain a stable ci/ca ratio because both vapor pressure deficit and temperature were decreased under glacial conditions at La Brea, and these have compensating effects on the ci/ca ratio. Reduced photorespiration at lower temperatures would partly mitigate the effect of low ci on gross primary production, but maintenance of present-day radial growth also requires a ~27% reduction in the ratio of fine root mass to leaf area. Such a shift was possible due to reduced drought stress under glacial conditions at La Brea. The necessity for changes in allocation in response to changes in [CO2] is consistent with increased below-ground allocation, and the apparent homoeostasis of radial growth, as ca increases today.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/68718
Item Type	Article
Refereed	No
Divisions	Science > School of Archaeology, Geography and Environmental Science > Department of Geography and Environmental Science
Publisher	Nature Publishing Group
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