Where does the carbon go? A model-data intercomparison of vegetation carbon allocation and turnover processes at two temperate forest free-air CO2 enrichment sites.
Bottom Line: Observed eCO2 effects on allocation were dynamic.Allocation schemes based on constant fractions or resource limitations performed less well, with some models having unintended outcomes.Our recommendations to reduce uncertainty include: use of allocation schemes constrained by biomass fractions; careful testing of allocation schemes; and synthesis of allocation and turnover data in terms of model parameters.
Affiliation: Department of Biological Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia.Show MeSH
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Mentions: Differences in model predictions of ambient LAI are discussed in Walker et al. (2014); here we focus on the predicted eCO2 effecton LAI. This effect depends, first, on the NPP enhancement; second, on the change in allocation ofNPP to foliage; and, third, on any change in specific leaf area (SLA) with eCO2. Fig.4 shows the observed and modelled responses of NPP, foliarbiomass, SLA and LAI to eCO2. Most models predict that eCO2 leads to anincrease in NPP, but there is a reduction in foliage allocation, such that the increase in foliagebiomass is less than the increase in NPP. These predictions are generally consistent with theobservations. The exception to this rule is ISAM at Oak Ridge, where foliage allocation increased,as explained above, leading to a larger response of foliage biomass than of NPP.
Affiliation: Department of Biological Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia.