Contrasting soil thermal responses to fire in Alaskan tundra and boreal forest
Rocha, Adrian V.
O’Donnell, Jonathan A.
Drysdale, Jessica A.
Rastetter, Edward B.
Shaver, Gaius R.
MetadataShow full item record
Recent fire activity throughout Alaska has increased the need to understand postfire impacts on soils and permafrost vulnerability. Our study utilized data and modeling from a permafrost and ecosystem gradient to develop a mechanistic understanding of the short- and long-term impacts of tundra and boreal forest fires on soil thermal dynamics. Fires influenced a variety of factors that altered the surface energy budget, soil moisture, and the organic-layer thickness with the overall effect of increasing soil temperatures and thaw depth. The postfire thickness of the soil organic layer and its impact on soil thermal conductivity was the most important factor determining postfire soil temperatures and thaw depth. Boreal and tundra ecosystems underlain by permafrost experienced smaller postfire soil temperature increases than the nonpermafrost boreal forest from the direct and indirect effects of permafrost on drainage, soil moisture, and vegetation flammability. Permafrost decreased the loss of the insulating soil organic layer, decreased soil drying, increased surface water pooling, and created a significant heat sink to buffer postfire soil temperature and thaw depth changes. Ecosystem factors also played a role in determining postfire thaw depth with boreal forests taking several decades longer to recover their soil thermal properties than tundra. These factors resulted in tundra being less sensitive to postfire soil thermal changes than the nonpermafrost boreal forest. These results suggest that permafrost and soil organic carbon will be more vulnerable to fire as climate warms.
Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Earth Surface 120 (2015): 363–378, doi:10.1002/2014JF003180.
Suggested CitationJournal of Geophysical Research: Earth Surface 120 (2015): 363–378
Showing items related by title, author, creator and subject.
Simultaneous determination of thermal conductivity, thermal diffusivity and specific heat in sI methane hydrate Waite, William F.; Stern, Laura A.; Kirby, S. H.; Winters, William J.; Mason, D. H. (Blackwell Publishing, 2007-03-11)Thermal conductivity, thermal diffusivity and specific heat of sI methane hydrate were measured as functions of temperature and pressure using a needle probe technique. The temperature dependence was measured between −20°C ...
Kneeland, Jessie M.; Hughen, Konrad A.; Cervino, James M.; Hauff, B.; Eglinton, Timothy I. (2013-06-13)Lipid content and fatty acid profiles of corals and their dinoflagellate endosymbionts are known to vary in response to high temperature stress. To better understand the heat stress response in these symbionts, we investigated ...
Forward scattering of a pulsed continuous wave signal through laminar and turbulent thermal plumes Bowen, Stephen G. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1993-09)The results of an experiment examining the forward propagation or an acoustic signal through a buoyant plume are discussed. Two distinct testing sights were used. One made use of a small fresh water tank in NUWC to provide ...