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

Author: Palmroth, Sari; Oren, Ram; McCarthy, Heather R.; Johnsen, Kurt H.; Finzi, Adrien C.; Butnor, John R.; Ryan, Michael G.; Schlesinger, William H.

Date: 2006

Source: Proceedings of the National Academy of Sciences. 103(51): 19362-19367

Description: 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 (L_D) 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 L_D to [approximately] 30%(200 gCm^-2y^-1) at the highest L_D. 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.

Keywords: forests, carbon, CO₂, free-air CO₂ enrichment (FACE), TBCA

View and Print this Publication (422 KB)

Pristine Version:  An uncaptured or "pristine" version of this publication is available. It has not been subjected to OCR (Optical Character Recognition) and therefore does not have any errors in the text. However it is a larger file size and some people may experience long download times. The "pristine" version of this publication is available here:

View and Print the PRISTINE copy of this Publication ()

Publication Notes: 

• We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
• This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

 Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

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.