Aboveground sink strength in forests controls the allocation of carbon below ground and its [CO2]-induced enhancement

  • Authors: Palmroth, Sari; Oren, Ram; McCarthy, Heather R.; Johnsen, Kurt H.; Finzi, Adrien C.; Butnor, John R.; Ryan, Michael G.; Schlesinger, William H.
  • Publication Year: 2006
  • Publication Series: Miscellaneous Publication
  • Source: Proceedings of the National Academy of Sciences. 103(51): 19362-19367

Abstract

The partitioning among carbon (C) pools of the extra C captured under elevated atmospheric CO2 concentration ([CO2]) determines the enhancement in C sequestration, yet no clear partitioning rules exist. Here, we used first principles and published data from four free-air CO2 enrichment (FACE) experiments on forest tree species to conceptualize the total allocation of to below ground (TBCA) under current [CO2] and to predict the likely effect of elevated [CO2]. We show that at a FACE site where leaf area index (L) of Pinus taeda L. was altered through nitrogen fertilization, ice-storm damage, and droughts, changes in L, reflecting the aboveground sink for net primary productivity, were accompanied by opposite changes in TBCA. A similar pattern emerged when data were combined from the four FACE experiments, using leaf area duration (LD) to account for differences in growing-season length. Moreover, elevated [CO2]-induced enhancement of TBCA in the combined data decreased from [approximately] 50% 700 g(Cm-2y-1) at the lowest LD to [approximately] 30%(200 gCm-2y-1) at the highest LD. The consistency of the trend in TBCA with L and its response to [CO2] across the sites provides a norm for predictions of ecosystem C cycling, and is particularly useful for models that use L to estimate components of the terrestrial C balance.

  • Citation: Palmroth, Sari; Oren, Ram; McCarthy, Heather R.; Johnsen, Kurt H.; Finzi, Adrien C.; Butnor, John R.; Ryan, Michael G.; Schlesinger, William H. 2006. Aboveground sink strength in forests controls the allocation of carbon below ground and its [CO2]-induced enhancement. Proceedings of the National Academy of Sciences. 103(51): 19362-19367
  • Keywords: forests, carbon, CO2, free-air CO2 enrichment (FACE), TBCA
  • Posted Date: December 12, 2006
  • Modified Date: April 6, 2007
  • Requesting Print Publications

    Publication requests are subject to availability. Fiscal responsibility limits the hardcopies of publications we produce and distribute. Electronic versions of publications may be downloaded, distributed and printed.

    Please make any requests at pubrequest@fs.fed.us.

    Publication Notes

    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
    • Our online publications are scanned and captured using Adobe Acrobat. During the capture process some typographical errors may occur. Please contact the SRS webmaster if you notice any errors which make this publication unusable.
    • To view this article, download the latest version of Adobe Acrobat Reader.