As climate warming brings more wildfire to the North, scientists and citizens wonder how the landscape will be transformed. Will forests continue their 2000’s-era trend toward less spruce and more hardwoods, catalyzed by larger fires and more frequent burning? If so, that might slow down the trend for larger and more intense fires. However, will hotter summers with more effective drying lead to increased fire re-entry into the early successional hardwoods, making them less strategic barriers for fire protection? A research team modeling the former question just unveiled an interactive web tool to model forest changes under various future climate scenarios (Feb. 1 webinar recording available HERE). With the new web tool, funded by JFSP, Paul Duffy and Courtney Schultz will be working with fire managers in Alaska to look at fire occurrence and cost in the future. Try it for yourself at http://uasnap.shinyapps.io/jfsp-v10/
Estimates of carbon released from combustion of vegetation and organic soil during wildfires have improved dramatically over the past decade. Biomass inventory, fire effects and fire severity studies have contributed more accurate data to improve these models. (See Ottmar 2007, Brendan Rogers webinar 2015) However, figuring out the net effect of all the various effects of fire, the recovery phase and warming climate on the carbon stored in Alaska’s forests and tundra is a lot more challenging! You’d have to consider changes in burn extent and/or severity, increases in plant productivity in recovering burns, changes in species composition and what that means for productivity, changes in permafrost distribution and soil C decomposition, methane emissions and carbon fluxes in lake systems and wetlands–etc.! A team lead by Dr. Dave McGuire at UAF has taken on this modeling challenge by applying their Integrated Ecosystem Model (IEM) which includes modules for fire, permafrost, and carbon cycling. Dave recently presented an overview of their findings at an IARPC-WCT/AFSC joint webinar (available HERE). In a nutshell, they found: 1) tundra holds 2x the carbon that boreal forest does in the same area 2) there has been a net C loss from boreal land area of about 8 Tg/yr over the last 60 years, primarily driven by large fires during the 2000’s 3) arctic tundra and SE Alaska still act as C sinks, compensating for these losses so that overall, Alaska sequesters about 3.7 Tg/yr, 4) increases in fire extent predicted with with warming climate will release even more C, but longer growing seasons and increased plant growth (as much as 8-19% increased productivity throughout the remainder of this century) with warmer climate and higher CO2 concentration in the atmosphere are estimated to offset these losses under most of the climate projection scenarios. Since this nutshell summary glosses over a lot, you should take a look at the presentation and the SNAP projects page with information on scenarios and the individual models used.
Boundary Fire near the Canadian border 2005 (Photo: Tony Chapman, BLM Alaska Fire Service)
Will climate-driven changes in fire regime affect the Porcupine Caribou Herd? Caribou actively seek out and rely on high-energy lichen-rich habitats in the winter, and these lichen stands–also known as “caribou moss”– are uniquely sensitive to fire, requiring 60-100 years to recover after burning. Alaska climate modelers and biologists teamed up to study predicted annual acreage burned in the ranges of two northern herds: the Central Arctic Herd and the Porcupine Caribou Herd (of Arctic National Wildlife Refuge fame). Using newly developed models of wildfire response to climate changes, Gustine et al. (2014) modeled burn acreage in the next few decades under two possible climate trajectories: let’s call them “warm” or “hot”. Under the “warm” scenario they found little change through 2090 in the total old-growth habitats available to caribou of either herd. However, the “hot” climate scenario indicated fires grew larger, increasing average area of winter habitat that burned per decade. In brief, the Central Arctic Herd lost 11% of their winter habitat and the Porcupine Herd lost 21% through 2090 under the “hot” scenario. In addition, 30% of the Porcupine Herd’s current spruce forest habitat changed to a younger forest type or tundra. While biologists continue to debate how much habitat is required to sustain herds at present levels, habitat loss is rarely beneficial and availability of old-growth lichen stands is a big driver of caribou use patterns in most Alaska herds. If we humans have the power to rein in the pace of climate change to the “warm” scenario by slowing our greenhouse gas emissions, the caribou would probably appreciate it. This short illustrated paper is open access—read the whole research article at:
Citation: Gustine, D.D., Brinkman, T., Lindgren, M., Schmidt, J.I., Rupp, T.S., and Adams, L.G., 2014, Climate-driven effects of fire on winter habitat for caribou in the Alaskan-Yukon Arctic: PLOS One, v. 9, no. 7 100588, doi:10.1371/journal.pone.0100588
The Joint Fire Science Program is doing a nation-wide survey this spring (2014) to ask managers whether sponsored research in their respective regions has improved management decisions or is useful to fire management practices. We started thinking about this for Alaska and prepared a 2-page review of a sample of four projects dating back to 2002 to see whether they have had any impact on management in Alaska, and what their outcomes appear to be today. Principal investigators included Scott Rupp (UAF), Phil Higuera (University of Idaho), Dan Mann (UAF), and Teresa Hollingsworth (USFS-Fairbanks). Read our review and see if you think these projects were indeed worthwhile!