MECHANICAL AND PRESCRIBED FIRE FUEL TREATMENTS: The Fire and Fire Surrogate Study at Blodgett Forest Research Station Professor Scott Stephens, P.I. & Jason Moghaddas, Fire Ecologist, Plumas National Forest The Fire Surrogate Study Research Team U.C. Berkeley Fire Science Laboratory Presentation Outline: 1. Blodgett History and Fire Surrogate Study Overview 2. Vegetation, Fuels, & Fire Behavior Results 3. Summary and Discussion BLODGETT FOREST RESEARCH STATION Georgetown, CA Management History (4400 acres): ¾ 1849-1900: Grazing, removal of some sugar and ponderosa pine; more intensive logging by oxen in the 1890’s ¾ 1900-1913: Extensive railroad logging over most of forest. UC in 1933. Fire Suppression is policy ¾ 1960-1970: Removal of most residual old trees ¾ 1849-1970: Common practice in Sierra ¾ 1975 on: Range of silvicultural treatments implemented; regular inventory plots and procedures implemented- HIGH SITE QUALITY Project Overview Æ Treatment Methods Æ Results Æ Summary BLODGETT FIRE HISTORY ANALYSIS (Stephens & Collins, 2004) ¾Over 60 fire scars cross dated. ¾Mean fire interval 4.7 years ¾Fire interval range 4-28 years ¾Most fires occurred in dormant season (September-October) ¾Fires stop after 1910 Project Overview Æ Treatment Methods Æ Results Æ Summary Fire Surrogate Study: What Types of Questions Are We Trying to Answer? ¾Can forest structure and process (fire) be altered in a way that will measurably reduce fire related mortality within a given stand? ¾Can “standard treatment practices” (thinning, burning) available locally be utilized to achieve this goal? ¾Can these practices be used to effectively modify fire behavior? ¾What are the ecological effects and economic costs of using these practices? Project Overview Æ Treatment Methods Æ Results Æ Summary Where Is the Study Taking Place? Eastside Cascades Northern Rockies Blue Mountains Southern Cascades Ohio Hills Central Sierra Southern Sierra • Southern Piedmont Appalachians Southwest Plateau Jemez Mountains • Southern Alabama Coastal Plain VISIT YOUR LOCAL FFS SITE! Site locations for the National Fire and Fire Surrogate Study Core response variables - economics & wood product utilization - fire behavior, fuels, smoke - insects - pathogens - soil & forest floor - vegetation - wildlife Project Overview Æ Treatment Methods Æ Results Æ Summary Treatment Goals & The “Desired Future Condition” “Each non-control treatment shall be designed to achieve stand and fuel conditions such that, if impacted by a head fire under 80th percentile weather conditions, at least 80 percent of the basal area of over story (dominant and co-dominant) trees will survive.” Project Overview Æ Treatment Methods Æ Results Æ Summary “Future of the Forest” “The Old Forest of the west slope of the Sierra will have been cut away, And the young growth will consist largely of red fir, white fir, and incense cedar” (Leiberg, 1902) Photo From R.S. Polkinghorn-”Pino Grande” What should the “desired future condition” look like? Project Overview Æ Treatment Methods Æ Results Æ Summary Blodgett Site “Desired Future Conditions” AVERAGE: ¾Crown cover………………~45%; 15-20% overlap of dominant & co-dominant trees ¾Basal area…………………~125ft2/acre ¾Height to crown base……..~10 feet ¾Surface fuel load………….~10 tons/acre ¾Duff/litter cover……………~75% ¾Duff/litter depth……………~2-3 inches ¾Snags >12”DBH/acre……..~3-5 ¾LWD >12” diam/acre……..~5-7 pieces Project Overview Æ Treatment Methods Æ Research Æ Results Æ Summary How do we achieve the “desired future conditions? 12 Treatment Units ¾Replicated, randomized design with controls. ¾3 controls ¾3 mechanical only ¾3 mechanical plus fire ¾3 fire only ¾All units 40-70 ac in size ¾All units are in “group selection” silvicultural system Project Overview Æ Treatment Methods Æ Research Æ Results Æ Summary Blodgett Forest Study Site: Treatment Unit Details Matrix ¾25-acre measurement area ¾Plots on 3-chain spacing ¾3 age classes of groups ¾100 foot buffer area around treatment unit Project Overview Æ Treatment Methods Æ Research Æ Results Æ Summary Groups What Tool Does FFS Use To Achieve DFC’s? ¾Control: No treatment of vegetation during the study period ¾Mechanical only: Commercial harvest followed by mastication of 90% of material less than 10 inches DBH ¾Mechanical plus fire: Identical to mechanical only but followed by a prescribed burn treatment of surface fuels ¾Fire only: No mechanical treatments; prescribed burn treatment of surface fuel only Project Overview Æ Treatment Methods Æ Research Æ Results Æ Summary Post Treatment Vegetation Structure PO ST T R E AT M EN T : C anopy C ov e r 100 a 80 b ab b % 60 40 20 ¾Canopy cover was (P <0.05) reduced in mechanical only and mechanical plus fire treatment types 0 CONTROL MECH ONLY 600.0 FIRE MECH + FIRE PO ST T R EAT M EN T : T re e s pe r Acre >1 Inch D B H a 500.0 TPA 400.0 300.0 ¾Trees per acre > 1 inch DBH were reduced (P <0.05) in all active treatment types b b 200.0 b 100.0 0.0 CONTROL MECH ONLY FIRE MECH + FIRE Project Overview Æ Treatment Methods Æ Results Æ Summary Post Treatment Fuel Loading POST TREATMENT: Litter and Duff Load per Acre 40.0 a a Tons Per Acre 30.0 20.0 b 10.0 0.0 10 CONTROL MECH ONLY b MECH + FIRE POST TREATMENT: 1, 10, and 100 Hour Fuel Load per Acre a Tons Per Acre FIRE a 5 b b 0 CONTROL MECH ONLY FIRE ¾Litter and duff loads were reduced (P <0.05) in fire only only and mechanical plus fire treatment types ¾1, 10, & 100 hour fuel loads were reduced (P <0.05) in fire only and mechanical plus fire treatment types. ¾1,000 hour sound and rotten reduced (P <0.05) in fire only and mechanical plus fire treatment types (not shown) MECH + FIRE Project Overview Æ Treatment Methods Æ Results Æ Summary Post Treatment Crowning and Torching Index: 90th Percentile Weather Conditions POST TREATMENT: Crowning Index (Miles per Hour) 40 b b ¾Crowning index was increased (P <0.05) in mechanical only and mechanical plus fire treatment types Miles per Hour 30 a a 20 10 0 CONTROL MECH ONLY FIRE MECH + FIRE POST TREATMENT: Torching Index (Miles per Hour) 500 c Miles per Hour 400 b 300 ¾Torching index was increased (P <0.05) in fire only and mechanical plus fire treatment types 200 100 a a 0 CONTROL MECH ONLY FIRE MECH + FIRE Project Overview Æ Treatment Methods Æ Results Æ Summary Predicted Probability of Mortality: 90th Percentile Weather Conditions 100 POST TREATMENT: Percent Probability of Mortality, Trees >1 Inch DBH b 80 b % 60 a 40 a 20 0 CONTROL MECH ONLY FIRE MECH + FIRE ¾Percent probability of mortality of trees >1” DBH was reduced (P <0.05) in fire only and mechanical plus fire treatment types ¾Predicted mortality similar (<8%) for trees >20” DBH for treated units Project Overview Æ Treatment Methods Æ Results Æ Summary No Treatment- tradeoffs ¾Retains Canopy Cover ¾Retains all surface fuels and CWD ¾Retains all ladder fuels ¾Does not reduce probability of torching and crowning ¾Which stand type would you want next to your house (all tx) ? Harvest + Mastication- tradeoffs ¾Can decrease canopy cover- depends on treatment intensity ¾Can increase surface fuels and CWD ¾Reduces ladder fuels ¾Reduces probability of torching and crowning ¾Reduction in annual volume growth Harvest + Mastication + rx fire- tradeoffs ¾Can decrease canopy cover- depends on treatment intensity ¾Kills existing regeneration ¾Decreases surface fuels and CWD, especially rotten CWD ¾Existing snags may be burned up but new ones created ¾Reduces ladder fuels ¾Reduces probability of torching and crowning ¾Risk of escape ¾Potential for smoke impacts to local and regional air shed ¾Less need for re-burn as there are fewer dead small trees Fire only- tradeoffs ¾Can maintain overstory canopy cover; ¾ Kills understory trees and existing regeneration ¾Decreases surface fuels and CWD, especially rotten CWD ¾Existing snags may be burned up but new ones created ¾Reduces ladder fuels ¾Reduces probability of torching and crowning ¾Risk of escape ¾Potential for smoke impacts to local and regional airshed ¾Will likely need re-entry to burn deadfall created from scorch related mortality How do we verify our modeled results? ¾Study behavior of treatments in “real” burns (i.e. Cone Fire, Hayman Fire). ¾Talk to fire management personnel- they have EXTENSIVE experience observing real fire behavior under almost all fuel loadings, extreme weather conditions, and in the WUI. ¾Research which “captures” the knowledge of experienced fire personnel should be funded- many are retiring soon! Above photo by Karen Wattenmaker; All photos posted by the National Interagency Fire Center, http://www.nifc.gov Acknowledgements •Funded by Joint Fire Science Program & The Resource Legacy Fund Foundation •Scott Stephens, P.I. •Fire Surrogate Study Research Team •Center for Forestry, Blodgett Forest Research Station •2001-2003 field technicians ¾We know how to create a “fire safe” stand structure in mixed conifer forests- many “fire safe” structures seen on field tour ¾Each forest has shared and unique constraints QUESTIONS? •http://www.fs.fed.us/ffs/ -Fire Surrogate Study •http://nature.berkeley.edu/stephens-lab/ -U.C. Fire Science Lab •http://www.cnr.berkeley.edu/forestry/ -U.C. Center For Forestry