NCEAS Project 2178

Towards an explicit representation of root distributions in global models

  • Robert B. Jackson

Jochen Schenk, Postdoc:

ActivityDatesFurther Information
Workshop2nd—4th October 1996Participant List  
Postdoctoral Fellow1st May 1998—30th April 1999Participant List  

Members Only Area

Abstract
Mechanistic models that examine the feedbacks between vegetation and climate (including atmospheric CO2) are critical for predicting the consequences of global change. Currently, the best and most explicit descriptions of root distributions in ecosystem, biome, and global models are simple two- or three-layer representations that separate shallow and deep water at arbitrary depth (e.g., Neilson 1995). We recently completed a literature review of root distributions for terrestrial biomes and various plant functional groups (Jackson et al. 1996; Canadell et al. 1996), with the goal of providing quantitative root distributions for global models. In this proposal, we highlight results of that literature synthesis and outline ways that root distributions could be incorporated into existing models (including BIOME-BGC, CASA, CENTURY, Heimann, MAPSS, BIOME2, SIB2, and TEM). We propose to hold two short-term workshops at the NCEAS to accomplish this goal. In the first workshop, participants will meet in Santa Barbara to review models, receive input from specific model developers, and propose model exercises. After this workshop, participants will modify model code as necessary, test the adjusted models, and then return to the NCEAS to run a joint modeling exercise. Our ultimate goal is to incorporate root distributions into the three or four models best suited to assessing global C, H2O, and nutrient fluxes, including at least one GCM. NCEAS funds requested in this proposal are leveraged by a financial contribution from BAHC (Biological Aspects of the Hydrological Cycle), with interest in the global consequences of rooting depth for climate and hydrology models.

TypeProducts of NCEAS Research
Journal Article Gordon, Wendy; Jackson, Robert B. 2000. Nutrient concentrations in fine roots. Ecology. Vol: 81. Pages 275-280.
Journal Article Jackson, Robert B.; Mooney, Harold A.; Schulze, E. D. 1997. A global budget for fine root biomass, surface area, and nutrient contents. Proceedings of the National Academy of Sciences. Vol: 94. Pages 7362-7366.
Book Chapter Jackson, Robert B. 1999. The importance of root distributions for hydrology, biogeochemistry, and ecosystem functioning. Edited by Tenhunen, J.; Kabat P. J.. Integrating Hydrology, Ecosystem Dynamics, and Biogeochemistry in Complex Landscapes. John Wiley and Sons, Ltd.. Chichester. Pages 219-240.
Report or White Paper Jackson, Robert B. 1999. Towards an Explicit Representation of Root Distribution Global Models. (Online version)
Journal Article Jackson, Robert B.; Schenk, H. Jochen; Jobbagy, Esteban G.; Canadell, Josep G.; Colello, Greg; Dickinson, Robert; Field, Christopher B.; Friedlingstein, Pierre; Heimann, Martin; Hibbard, Kathy A.; Kicklighter, David W.; Kleidon, Axel; Neilson, Ronald; Parton, William J.; Sala, Osvaldo E.; Sykes, Martin. 2000. Belowground consequences of vegetation change and their treatment in models. Ecological Applications. Vol: 10(2). Pages 470-483.
Data Set Jackson, Robert B.; Gordon, Wendy. 2004. Global compilation of fine-root nutrient concentrations and root diameter. (Online version)
Data Set Jackson, Robert B.; Gordon, Wendy. 2004. Global distribution of root nutrient concentrations in terrestrial ecosystems. (Online version)
Data Set Jackson, Robert B.; Schenk, H. Jochen. 2004. Global distribution of root profiles in terrestrial ecosystems. (Online version)
Data Set Jackson, Robert B.; Gill, R. 2004. Global distribution of root turnover in terrestrial ecosystems. (Online version)
Journal Article Schenk, H. Jochen; Jackson, Robert B. 2002. Rooting depths, lateral root spreads and below-ground/above-ground allometries of plants in water-limited ecosystems. Journal of Ecology. Vol: 90(3). Pages 480-494.
Journal Article Schenk, H. Jochen; Jackson, Robert B. 2002. The global biogeography of roots. Ecological Monographs. Vol: 72. Pages 311-328.
Journal Article Schenk, H. Jochen; Jackson, Robert B. 2005. Mapping the global distribution of deep roots in relation to climate and soil characteristics. Geoderma. Vol: 126(1-2). Pages 129-140.
Journal Article Schenk, H. Jochen. 2008. The shallowest possible water extraction profile: A null model for global root distributions. Vadose Zone Journal. Vol: 7(3). Pages 1119-1124. (Online version)