Climate change and wildfire Research at the PNW Station: past, present, future Don McKenzie (TCM/FERA) with contributions from PNW Science Day March 12, 2014 Paul Hessburg Becky Flitcroft Sim Larkin John Kim

Rationale ✤ It’s getting warm down here. ✤ No “hiatus” in hot extremes over land. ✤ More area is expected to burn. ✤ What we care about is how fire climatology translates to the issues and scales relevant to land management. Fire effects: tree mortality, smoke and air quality, habitat structure and pattern, regeneration and forest succession. Time domains: immediate (to 2020s), next generation (2040s), long-term (2060s and beyond). Uncertainties grow non-linearly over time. Space domains: cross-scale, from watersheds (“landscapes”) to the region. Specificity: fire regimes. It’s not about individual fires or “my favorite pixel”. Seneviratne et al. (2014) (though not so much as on this map)

Past and present research (1) ✤ Drivers of area burned ✤ Fire-climate models at the scales of ecosections project that the West will burn up. ✤ Expectation breaks down because there are limitations. Fire area can’t keep increasing because fires will run out of real estate. “Hotter and drier = more fire” doesn’t work everywhere. Best in the dark green ecosections. Expectation: Hotter and drier = more fire! Correlations between annual area burned and water-balance deficit Temperate rain forests: extreme weather causes rare wildfires. Transitional forests: drought stress will increase fire extent and severity. Arid forests: fire extent and severity may actually decrease.

Past and present research (2) ✤ Smoke and air quality (AirFire/FERA — Larkin/McKenzie) ✤ Smoke modeling framework (BlueSky) that accepts either observed or simulated (i.e., future) fires. ✤ Stochastic fire simulator tuned to the spatio- temporal domains of air-quality models. McKenzie et al. (2014)

Past and present research (3) ✤ Future megafires (AirFire/FERA — Larkin/McKenzie) ✤ Expectation of more extreme events based on projections of future fire weather. ✤ Representing all the factors that combine to produce a megafire. Weather pre-ignition conditions fuels. Weather on the day or hour of the fire. Escapes initial attack? (hard to model but a big source of uncertainty) Weather in days or weeks following fire. ✤ How will this change in a warming climate? Downscaling climate models. Different regions will see different fire weather (not always hotter and drier). Stavros et al. (2014)

Past and present research (4) ✤ Fire and landscape dynamics (EPF/CLI — Hessburg) ✤ Patch-size distributions associated with future climate. Topographic controls based on terrain patch structure. Endogenous vs. exogenous controls on fire & other disturbance. ✤ Restore and maintain ecosystem function in future climate. Use topography as a template. Patch structure and tree density tuned to “climate analog” reference conditions rather than HRV. Anticipate patterns of fire severity and seral stages.

Past and present research (5) ✤ Fire, climate change, and bull trout vulnerability (LWM/AEM — Flitcroft) ✤ Patch-size distributions associated with future climate. ✤ Habitat extent of cold water aquatic species is vulnerable to climate change. ✤ Climate change may isolate small patches of habitat, often in the headwaters of a watershed. ✤ Wildfire may compound the negative effects of climate change for cold water species. ✤ Some management action to reduce wildfire effects may serve to protect some cold water aquatic refugia.

Past and present research (6) ✤ Process-based modeling of climate, vegetation, fire (EPF/CLI — Kim) ✤ MC2 DGVM simulates vegetation-fire interactions at multiple scales. Global, CONUS, regional. Currently studying R6, R5, R4, R1, and Blue Mountains Ecoregion. ✤ MC1-based Seasonal Drought and Fire Forecasting System creates 7-month fire and drought forecasts, updated monthly. ✤ Downscaled output from CMIP5 GCM projections used to drive DGVM and predict changes in fire. Projections of biomass consumed by wildfire: vs

Future research (1): categories Field & remote-sensing studies ‣ Fire and succession ‣ Fire and other disturbances ‣ Fire and carbon Theory ‣ Conceptual models ‣ Scaling ‣ Extreme events and thresholds Models ‣ Landscape projections ‣ Process AND empirical ‣ “As simple as possible, but no simpler” Fire Subalpine fire and succession (Cansler 2014) Kellogg et al. (2008)

Future research (2): questions How much, how quickly? ‣ High-severity patches ‣ Carbon source ‣ Air quality Where? ‣ Vulnerable landscapes ‣ Thresholds for species and life forms (e.g., forest ➛ shrubland) ‣ Thresholds for processes (e.g., habitat connectivity) What can we do? ‣ Resistance (short-term) ‣ Resilience (mid-term) ‣ Adaptation (start now) ?

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