OGWC – Forest C Bev Law Prof. Global Change Biology & Terrestrial Systems Science Oregon State University Oct 6, 2016

Fire Emissions Annual Net Ecosystem Carbon Balance = NEP – fire emissions – harvest emissions NEP = Aboveground NPP – dead wood decomposition – litterfall + Δ root +Δ soil C 2001-2010: FS estimate was “area at risk.” OSU estimate for 2001-2010 based on fire severity burn area (L, M, H) and region- and pool-specific combustion factors (OSU sum=11.4 TgC) FS est of Ha at risk = 26 x MTBS estimates (total for 10 yrs) TgC/ha = 4.37 x avg calculated from OSU ha burned OSU est: Actual fire emissions were calculated using burn area and severity (MTBS) and biomass-specific combustion factors for the region, including live and dead pools. The studies represent several of the dominant forest types in our region covering 67% of the forested area. (Updated Hudiburg et al. 2011)

OSU estimate of fire emissions in Oregon (Annual for 2001-2014) Sum 11.42 Tg C emissions 2001-2010 Fire emissions averaged 1.14 Tg C yr-1, ~9% of the equivalent FFE for Oregon (updated years Hudiburg et al. 2011)

Wildfire in Oregon 1984-2014 (length of record) Wildfire Trends 1984-2014 2015 Wildfire Detections Percent of Burn Area by Severity Credit: USDA FS RSAC MODIS Active Fire Detections Since Jan. 1, 2015 2015 Statistics from: http://wildfireoregondeptofforestry.blogspot.com/ Fire season officially ended Oct 28, but there could be more. 87,584 acres shown as gray bar in lower plot – is the ODF protected forestland burned area – total area most likely much larger, especially considering the 631K number given. “forestland jurisdictions” are e.g. FS, ODF forested areas “In 2015, more than 631,000 acres burned on all forestland jurisdictions in Oregon. Firefighting costs totaled $240.5 million” – statement from the blogspot website above ($183M in 2013, when burn area was comparable to 2015) All other years (1984-2015) from MTBS data. Map is current as of Nov 3, 2015 No significant trend in area burned and total number of fires No significant trend toward high severity 87K acres burned on lands protected by ODF Human-caused ignitions ~75% of total (Adapted from Law & Waring, 2015; Oregon data only; www.mtbs.gov)

Biomass Mortality From Wildfires in Oregon 1984-2012 Forest mortality from fire (1984-2012) and insects (1997-2012) across Oregon. Neither time series showed a significant (P<0.05) trend. Biscuit Fire mortality shows up over this period as the dominant include. No significant trend in biomass mortality (data from Law & Waring, 2015, Berner et al. in review)

Oregon annual C emissions and forest C sink Fire emissions were 17% of sum of fire and harvest emissions/yr All unreserved forests Harvest emissions = residue + wood lost in mfr + wood decomposition over time from product use Fire emissions = severity area burned x pools x region-specific combustion factors (live, dead, surface litter) (Hudiburg et al. 2011, updated)

Future Scenario Thin only forests where MFRI<40 yrs 35% of biomass per unit area East-side: 14 Tg C net emissions over next 30 years CLM+LCA (Hudiburg et al. EST 2013)