Canopy nitrogen, carbon assimilation, and albedo in temperate and boreal forests: Functional relations and potential climate feedbacks.

Published

Journal Article

The availability of nitrogen represents a key constraint on carbon cycling in terrestrial ecosystems, and it is largely in this capacity that the role of N in the Earth's climate system has been considered. Despite this, few studies have included continuous variation in plant N status as a driver of broad-scale carbon cycle analyses. This is partly because of uncertainties in how leaf-level physiological relationships scale to whole ecosystems and because methods for regional to continental detection of plant N concentrations have yet to be developed. Here, we show that ecosystem CO(2) uptake capacity in temperate and boreal forests scales directly with whole-canopy N concentrations, mirroring a leaf-level trend that has been observed for woody plants worldwide. We further show that both CO(2) uptake capacity and canopy N concentration are strongly and positively correlated with shortwave surface albedo. These results suggest that N plays an additional, and overlooked, role in the climate system via its influence on vegetation reflectivity and shortwave surface energy exchange. We also demonstrate that much of the spatial variation in canopy N can be detected by using broad-band satellite sensors, offering a means through which these findings can be applied toward improved application of coupled carbon cycle-climate models.

Full Text

Duke Authors

Cited Authors

  • Ollinger, SV; Richardson, AD; Martin, ME; Hollinger, DY; Frolking, SE; Reich, PB; Plourde, LC; Katul, GG; Munger, JW; Oren, R; Smith, M-L; Paw U, KT; Bolstad, PV; Cook, BD; Day, MC; Martin, TA; Monson, RK; Schmid, HP

Published Date

  • December 3, 2008

Published In

Volume / Issue

  • 105 / 49

Start / End Page

  • 19336 - 19341

PubMed ID

  • 19052233

Pubmed Central ID

  • 19052233

Electronic International Standard Serial Number (EISSN)

  • 1091-6490

International Standard Serial Number (ISSN)

  • 0027-8424

Digital Object Identifier (DOI)

  • 10.1073/pnas.0810021105

Language

  • eng