| Forest fires release carbon to the atmosphere during combustion, followed by smaller releases during subsequent years as decomposition and respiration occur. Recent climate change predictions suggest an increase in wildfire in the western US, potentially leading to more carbon emissions. My goal was to answer three broad questions: a) how much CO2sub> efflux is respired from soil after fire? b) how is montane forest biomass distributed, and how much aboveground carbon is lost due to fire? and c) what is the difference in the spatial extent of fire and the magnitude of carbon emissions from fire during pre-European and contemporary years?;I used a portable infrared gas analyzer to evaluate the interaction between soil water and prescribed fire on soil respiration one year post-fire in three burned and unburned areas in the montane Pinus ponderosa forests of Colorado, and found that soil respiration rates were highly variable (<0.01-2.8 g C m-2 hr-1). Prescribed fire did not significantly affect soil respiration, however, water availability increased respiration responses at both burned and unburned sites.;I estimated aboveground biomass distribution and carbon loss due to fire in a montane landscape that included 7 vegetation types. Over 75% of the aboveground biomass across the 600 square km study area was stored in coniferous vegetation. Over 80% of aboveground biomass across the landscape remained post fire, with 68% stored in coniferous vegetation. A typical low to moderate severity fire in the montane forest released 25 +/- 8 Mg C ha -1.;I used national data sets, tree-ring data, and recent fire records to determine the spatial extent and magnitude of C emissions from pre-European and contemporary fires. Wildfires were more spatially extensive during the pre-European period (an average of ∼33,347 ha yr-1burned) as compared to the contemporary period (an average of ∼2,240 ha yr --1). Average yearly C loss estimates from the Pre-European period were considerably larger (2,506,441 +/- 1,274,179 Mg yr -1) compared to the contemporary estimate (11,889 +/- 6,342 Mg yr-1).;My results provide insight into carbon distribution patterns and expected emissions from fire in the montane forest region. Fire suppression has decreased the spatial extent of fire in this forest, and thus decreased pyrogenic carbon emissions. However, fire suppression and climate change increase the likelihood of large fires in the future, and my results suggest that carbon emissions from these forests could greatly affect the atmospheric pool. |
