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Fire Prevention as a GHG Mitigation Strategy Presented by Robert Beach, RTI International Brent Sohngen, The Ohio State University Presented at Forestry and Agriculture Greenhouse Gas Modeling Forum March 6-8, 2007 Shepherdstown, West Virginia.
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Fire Prevention as a GHG Mitigation Strategy Presented byRobert Beach, RTI InternationalBrent Sohngen, The Ohio State University Presented atForestry and Agriculture Greenhouse Gas Modeling Forum March 6-8, 2007Shepherdstown, West Virginia 3040 Cornwallis Road ■ P.O. Box 12194 ■ Research Triangle Park, NC 27709 Phone 919-485-5579 e-mail rbeach@rti.org Fax 919-541-6683 RTI International is a trade name of Research Triangle Institute
Introduction • Heightened concern in recent years that intensive human intervention may have made forests more susceptible to negative effects of wildfires • Evidence that fire management interventions such as prescribed burning and thinning can reduce potential hazards related to wildland fires by removing smaller materials that can act as ladders for fires • Healthy Forests Restoration Act called for widespread thinning in US forests in order to help make them less susceptible to the negative effects of fires • Potential for reduction in the impacts of fires suggests that additional short-term carbon emissions could lead to smaller emissions in the future if large fires are reduced • Implications for carbon sequestration in fire-prone stands • This is an exploratory study to examine the net carbon effects (accounting for time) of thinning using the Forest Vegetation Simulator-Fire and Fuels Extension (FVS-FFE) model
Study Region and Plots • Representative ponderosa pine stands in the Eastern Cascades region of Oregon • Region has been identified as having high build-up of fuels in forests, that could potentially lead to large-scale consequences if fires break out • Ponderosa pine is the dominant species in the Eastern Cascades • Plot data obtained from the US Department of Agriculture, Forest Service, Forest Inventory and Analysis
Models • Used FVS-FFE model to assess biomass stocks, thinning options, and simulated fire effects • FVS models stand dynamics, including growth of forests, mortality, and other attributes • The Fire and Fuels Extension can be used to model changes in biomass in different pools over time and to simulate the effects of a fire on these pools as well as modeling residual stand growth. • FFE can be used to simulate the effects of fires under different weather conditions • Examined carbon storage and emission profile over a 100-year period with and without thinning and with and without a fire
Models (2) • Fuel Reduction Cost Simulator (Fight et al., 2006) was used to estimate costs of extracting materials from thinning operations • Used cut list from FVS to identify the trees that were thinned • Benefits of extracting marketable materials were estimated using price data from the OR Dept of Forestry • Estimated non-CO2 emissions (methane, nitrous oxide) from wildfire using EPA emission factors
Assumptions • Thinning from below until 50 sq ft basal area • Material in the range of 5"-7" is used for pulp and material >7" dbh is used for sawtimber • All remaining material is assumed to be chipped and burned onsite, leading to an immediate emission • Calculate carbon stock in standing biomass using factors from Smith et al (2003)
Thinning without Fire • Immediate release of carbon from thinning • Thinned stand slowly begins to approach carbon storage of unthinned stand over time • PV of carbon change over 100 years from case study stand is -4.12 tC/ha without fire • PV of carbon change with fire is actually even more negative in this case at -4.95 tC/ha • Harvesting operation cost: $678/acre • Value of wood harvested: $498/acre • Net value: -$180/acre
Other Stands • Across the 487 ponderosa pine stands in the Eastern Cascades of OR available from FIA data • Over half had lower carbon emissions from fires when they had been thinned • However, only in a minority of cases (<20%) were the lower emissions from fire sufficient to offset the higher emissions from thinning
Timing of Thinning and Fires • We also examined a number of scenarios that varied the timing between thinning and the fire • Initially we thought that the findings may be related to the fire occurring shortly after thinning • However, it made relatively little qualitative difference in changes in carbon storage
Conclusions • Based on our simulations and assumptions, thinning tended to result in lower discounted net carbon storage • In the absence of wildfires, carbon storage is reduced relative to baseline due to the removal of carbon during thinning • With wildfires, the majority of plots examined did have lower emissions if they had been thinned, but not sufficiently lower to offset the emissions from thinning
Future Research/Extensions • Alternative fire models • FOFEM, CONSUME, others • Accounting for interactions with other stands • Prescribed burning • Quantify factors impacting effectiveness of thinning in reducing emissions • Include harvesting • Stochastic wildfires • Examination of climate effects