Wildfire and Carbon Storage
Wildfires are an important component of most terrestrial ecosystems. In many cases, fires are essential to the regeneration and health of forested ecosystems. Fires can also be destructive and the potential risk to structures has led to suppression of fires across a large portion of the Western US. These conflicting goals have been the focus of a great deal of discussion about appropriate forest management policy and that discussion is continuing today. As carbon management becomes more of a focus of land managers, fires represent an additional complication that will have to be addressed in policy development.
Research Results
Much of our field research has taken place in boreal ecosystems but we are increasingly focusing on studies in the Western US. Our work has been supported primarily by the USGS. A annotated bibliography of our work in this area is provided below. This is a research topic that we hope to continue to focus on in the lab with new projects in Colorado and the Western states.
C. Wiedinmyer and J.C. Neff. (2007). Estimates of CO2 from fires in the United States: Implications for Carbon Management. Carbon Balance and Management. 2:10. This study provides an estimate of CO2 emissions from wildland fires across the United States. We compare combustion losses to industrial emission for the US and on a state by state basis. We also highlight the large uncertainties related to estimates of fire emission estimates. The purpose of this paper is to place these episodic biogenic emissions in the broader context of continental scale carbon balance. Understanding the causes, variability and magnitude of these emissions is important to the development of wise emission policies. PDF
Randerson, J.T., H. Liu, M.G. Flanner, S.D. Chambers, Y. Jin, P.G. Hess, G. Pfister, M.C. Mack, K.K. Treseder, L.R. Welp, F.S. Chapin, J.W. Harden, M.L. Goulden, E. Lyons, J.C. Neff, E.A.G. Schuur, C.S. Zender. (2006). The Impact of Boreal Forest Fire on Climate Warming. Science V314 (5802). This manuscript presents a comprehensive analysis of the full radiative impact of boreal forest fire on atmospheric radiative balance. The study includes both the direct effects of fire and regrowth on atmospheric CO2 but also the impacts of changes in land surface energy exchange (at the site of fire and elsewhere due ot aerosol deposiion). PDF available on request
Harden J. W. , K. L. Manies, M.R. Turetsky, and J. C. Neff. (2006) Effects of wildfire and permafrost on soil organic matter and soil climate in interior Alaska. Global Change Biology. Published article online: 18-Oct-2006. doi: 10.1111/j.1365-2486.2006.01255.x This manuscript describes a study of soil carbon losses due to fire in interior Alaska. The study identifies drainage condition and permafrost presence as two fo the important controls on ground fuel C storage and loss. The presence of the deep soils layers, in partictular, is shown here to have a large influence on both carbon storage between burns, carbon loss with burning and is suggested to play an important role in regional regrowth patterns. PDF
Neff J.C., J.W. Harden, and G. Gleixner. Fire effects on soil organic matter content and composition in boreal interior Alaska. 2005. Canadian Journal of Forest Research. 35(9): 2178-2187 We present the results of a study of a burned area (from 1999) near Delta Junction, AK. We use several techniques to estimate pre and post fire soil carbon stocks and highlight the uncertainty in these different approaches to soil carbon estimation across heterogeneous boreal landscapes. We also use a combination of py GCMS and thermogravimetry to examine the structural changes that occur in soils with burning and suggest that these changes are dominated by the loss of thermally labile compounds rather than the creation of new char products. PDF
Harden, J. W.; Neff, J. C.; Sandberg, D. V.; Turetsky, M. R.; Ottmar, R.; Gleixner, G.; Fries, T. L.; Manies, K. L. Chemistry of burning the forest floor during the FROSTFIRE experimental burn, interior Alaska, 1999 Global Biogeochem. Cycles, Vol. 18, No. 3, GB3014 10.1029/2003GB002194 28 August 2004 This study focused on an experimental burn in the Poker/Caribou Creek experimental watershed near Fairbanks, AK. The study presents a technique for estimating soil organic matter consumption based on the concentrations of immobile elements in the soil profile (similar to weathering estimates). One additional interesting component of this study are the high concentrations of rock-derived minerals in the organic layers of this forest. These elements, which must largely be derived from dust, may play an important role in forest regeneration following fire. PDF