HR: 10:20h
AN: B42B-01 INVITED     [Abstracts]
TI: Fire, Carbon and Climate Change in Boreal Forests
AU: * Flannigan, M D
EM: mike.flannigan@nrcan.gc.ca
AF: Canadian Forest Service, 1219 Queen St. East, Sault Ste Mari, ON P6A 2E5 Canada
AU: Amiro, B D
EM: brian_amiro@umanitoba.ca
AF: University of Manitoba, Dept of Soil Science, Winnipeg, MB R3T 2N2 Canada
AU: Logan, K A
EM: kimlogan@nrcan.gc.ca
AF: Canadian Forest Service, 1219 Queen St. East, Sault Ste Mari, ON P6A 2E5 Canada
AB: Disturbances are the major stand-renewing agents for much of the circumboreal forest. In Canada, fire has received much of the attention in carbon cycle science because it affects about 3 million ha of Canadian forest annually, impacts air quality, and can threaten life, property and infrastructure. Fire affects the carbon balance through three processes. First, carbon and other greenhouse gases are emitted to the atmosphere during the combustion process. We estimate this to average about 27 Tg C/year in Canada over the past 40 years, which is close to 20% of industrial carbon emissions. However, in some years this can exceed 100 Tg C. Efforts are underway to estimate global fire activity and greenhouse gas emissions using observations, remote sensing and modelling. The second process is the decomposition of fire-killed vegetation. This forms a pool of coarse woody debris that can take decades to decompose, or can be quite rapid, depending on the post-fire environment. The third process is succession of vegetation following fire, a dynamic process that involves the interplay among species establishment and competition. Weather and climate affects all of these processes. Estimates of the future environment indicate that much of boreal Canada will experience warmer and drier conditions, although there will be regional differences and transient effects. The projections suggest that we may experience a doubling of area burned over the next century because of anthropogenic climate changes. This may have further implications to the global carbon budget by increasing atmospheric carbon dioxide concentrations. This increase in fire activity may lead to a positive feedback cycle with the increased release of greenhouse gases. A run-away scenario is unlikely because young successional boreal vegetation often does not burn as readily and would limit the positive feedback cycle. Also, changes to the forest composition following fire increases surface albedo and alters the energy balance; effects that may cause climate cooling. However, the impacts of landscape feedbacks and human intervention limiting future fire are not well known.
DE: 1610 Atmosphere (0315, 0325)
DE: 1626 Global climate models (3337, 4928)
SC: Biogeosciences [B]
MN: Fall Meeting 2005