Mountain Pine Beetle-Fire interactions in lodgepole pine forestsIntroduction to a session presenting recent work in Colorado, Wyoming, and CanadaJenny BriggsResearch EcologistRocky Mountain Geographic Science Center, US Geological Survey, Denver, Colorado January 19, 2011 Regional Prescribed Fire Workshop, USFS
Overview – 4 approaches (Jenny) • a. Observations • b. Experiments • c. Retrospective studies • d. Prospective studies - modeling • 2. MPB and fire: The BC experience (Dana Hicks) • – Approaches a, b • Additional perspectives & results from Canada (Brad Hawkes) • – Approaches a, b • Wildfire and bark beetle outbreak impacts in US lodgepole pine forests -including the post-fire picture(Dan Tinker) – Approaches c, d 5. Q and A – Discussion
Our “burning question”: How will Mountain Pine Beetle infestation impact fire behavior and effects in lodgepole pine forests? Three Lakes area, Grand County, CO 2008 Jenny Briggs
Typically moist climate – persistent winter snowpack, summer thunderstorms • Sparse understory, compact litter • Abundant down woody debris (DWD) and ladder fuels • Tightly compacted crowns • Many serotinous (heat-opening) cones Weather, not fuels = typical driver of fire in these forests “Normal” lodgepole forests: the poster child for infrequent, high severity fire regimes Laurie Huckaby Credit: Paula Fornwalt, USFS-RMRS. From: Romme et al. 2003. USDA Forest Service Gen. Tech. Rep. RMRS-GTR-114; Schoennagel et al. 2004. Bioscience 54: 661-676.
Insect-caused tree mortality in CO - Aerial Detection Surveys, USFS/CSFS
~ 3 million acres affected in CO and southern WY by MPB to date Jenny Briggs
MPB primarily affects 1 fire variable: FUEL • Where (distribution) • Surface: DWD, understory • Ladder • Overstory/Canopy Alters: canopy base ht, canopy bulk density, canopy closure Other fuel variables: • How much (loading) • How big (diameter size class) • How flammable (moisture content) • All measurements, plus weather = inputs to FIRE BEHAVIOR MODELS
Trees at different times since MPB attack Fader Early summer Green healthy tree TIME Before MPB attack Green-attack stage Between attack and next spring Red-attack stage 1 to 3 years after attack Grey-attack stage 3 to 5 years after attack Credit: J. Hicke and A. Meddens, U. Idaho
Ways scientists can study MPB-fire interactions Direct observations - More from Dana Hicks, Brad Hawkes b. Experiments (e.g. prescribed burns) - More from Dana Hicks, Brad Hawkes c. Retrospective studies of correlations - More from Dan Tinker d. Prospective studies using modeling - Based on measurements or predictions of changes in input variables, e.g. fuels - More from Dan Tinker
a. Direct observations: Fire in MPB-affected lodgepole forest, CO YMCA Camp fire, Grand Co., June 07 (~50 acres)
Fire in MPB-affected lodgepole forest, CO Church Park Fire, Grand Co., October 2010 (~300 acres)
b. Experiments • Some prescribed burning in MPB-affected forests in Canada • Challenging to implement/control/replicate! • Not yet published • Parks Canada (Kubian, Gray et al), BCFS (Dana Hicks et al), Natural Resources Canada (Brad Hawkes et al) – later talks! • Crown flammability study, Spring 2009: Rocky Mountain National Park and CSU (Drs. Romme & Rocca) • Small scale (<20 trees) • Winter conditions: low-risk
ROMO Crown Flammability Study: lit ~ 3 trees in each of 4 different post-MPB stages 1.5 yr post attack Fader Early summer Green healthy tree TIME Before MPB attack Green-attack stage Between attack and next spring Red-attack stage 1 to 3 years after attack Grey-attack stage 3 to 5 years after attack 2.5 yr post attack
Results: VIDEO: Torching only in crowns of “freshly” red trees, 1.5 yrs post-attack Photos/video: Nathan Williamson, ROMO Fire Ecologist
c. Retrospective studies • Analyze overlaps between previous fires and MPB-affected areas • Often use ADS surveys, maps, dendrochronologic records (tree ring histories), GIS • MORE INFORMATION in Dan Tinker’s talk!
d. Prospective studies: Measuring and modeling • Measure the fuels changes in MPB-affected forest plots • Input the new fuels data into physics-based models of fire behavior (e.g. in US – NeXus, Flammap, Farsite, FVS-FFE) • Run simulations with predicted weather to predict fires! • Relevant studies • Page W and M Jenkins, 2007a,b. Forest Science • Klutsch J et al. 2009. Forest Ecology and Management, 2010 Western Journal Applied Forestry (submitted) • Simard M et al., 2011. Ecol. Monographs • MORE INFORMATION in Dan Tinker’s talk!
2 studies: Klutsch et al. 2009, 2010 1 yr 2 yr 5 yr Measured stand/tree characteristics and fuels Predicted future fuel loads with 10% & 80% falling of infested trees Modeled fire behavior in FVS-FFE for all these current/future conditions • 221 plots in Grand County, CO • 2006 and 2007: 7 yrs after outbreak began • unaffected • recent (0-3 years since trees infested) • older (4-7 years since trees infested) Jen Klutsch, USFS-RMRS
Klutsch et al. Results – fire type 70 60 50 40 % of plots 30 20 10 0 uninfested 0-7 years after 10% infested 80% infested outbreak tree fall tree fall initiation Chi-square = 79.5, df=9, p-value<0.0001 • more active crown fire modeled for uninfested plots Jen Klutsch, USFS-RMRS
Some conclusions from US work to date • Little info from few wildfires/prescribed burns in MPB-affected forests so far • MPB alters fuels, but changes are patchy/variable within stands • Less active crown fire MODELED in infested plots- due to opened canopies? • Higher levels of passive (torching) fire MODELED - due to more surface/ladder fuels? • Weather may remain primary driver of fire in MPB forests Jenny Briggs • Existing US fire behavior models don’t • allow us to represent post-MPB conditions fully
Limitations of these scientific approaches a. Direct observations - Wildland fires = unpredictable, rare events; all different! b. Experiments - either difficult to implement safely, or small in scale/limited in realism c. Retrospective studies - Can’t standardize weather, fire behavior, etc - Spatial accuracy issues with historic maps/records d. Modeling - Current models/equations don’t accurately represent post-MPB fuels - Regeneration, succession, dead dry canopy fuels not included John Popp
Summary points • Tools and opportunities to study these complex natural and anthropogenic disturbances are limited. • Ecology has little in common with lab-based science where variables can be controlled and cause-and-effect relationships identified. • Fire scientists cannot do “fool-proof” studies to clearly answer “Will MPB change fire behavior and effects?” • Input from fire crews and fire managers will be key to help build information and predictions
…More soon from our Canadian colleagues…Questions & comments welcome! Acknowledgments: Paula Fornwalt and Jen Klutsch, USFS-RMRS