A paper just published by the indefatigable Adam Young, a PhD candidate at the University of Idaho, and colleagues pulls together a lot of information about climate, forest, tundra and fire to offer a glimpse of potential future fire regimes in different parts of Alaska. By looking at fire occurrence at a multi-decadal time scale, the researchers drill down into how fire rotations are likely to respond to climate projections at a regional scale.
Exerpt from Fig. 6, Young et al. 2016. Figures in the paper not only show the observed fire rotation for 19 subregions of Alaska (Figure A2 in supplement) with 60 years of fire occurrence data, but also project future rotations under various climate scenarios (in this case a mean of of 5 global climate models).
The use of advanced statistical models to build fire-landscape response models for boreal forest and tundra reaffirms prior findings of the sensitivity of fire regime to summer temperatures and moisture deficit. However, the effect is not uniform among regions: they identify a threshold at about 56⁰ F (30-yr mean temperature of the warmest month) and another threshold for annual precipitation where fire occurrence really seems to jump. This latter finding accounts for results which project large increases in 30-year probability of burning for areas where these thresholds will be crossed in the next several decades. For example, models project the Brooks Range foothills of the North Slope, Noatak tundra and the Y-K Delta may see increases in fire 4-20x greater than historical levels. Some tundra areas are likely to experience fire frequency increase to levels not observed in the paleo record, spanning the past 6,000-35,000 years. Across most of the boreal forest, fire rotation periods are projected to be less than 100 years by end of the 21st century. This is useful information for natural resources management as well as fire protection agencies—a concise, well-researched, well-illustrated paper—put it on your summer reading list.
Young, A. M., Higuera, P. E., Duffy, P. A. and Hu, F. S. (2016), Climatic thresholds shape northern high-latitude fire regimes and imply vulnerability to future climate change. Ecography 39: 1-12. http://dx.doi.org/10.1111/ecog.02205
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.
The 2007 Uluksian Fire (photo courtesy of P. Higuera).
Dr. Philip Higuera (assistant professor at the College of Natural Resources, University of Idaho) will be joining us for a webinar on May 24, 2012 (1:00-2:00 pm AKDT) entitled “Tundra burning in Alaska: Rare event of harbinger of climate change?”. Philip’s current research is focused on how climate, vegetation, and human activities interact with fire occurrence and fire regimes (from across years to across millenia). He is also the Director of the Paleoecology and Fire Ecology Lab where students and researchers work on charcoal and pollen analysis in lake-sediment records, dendrochronology, and spatially-explicit modeling and analyses for areas in the US Rocky Mountains, Alaska, and abroad in Tasmania, Australia.
Dr. Philip Higuera will be presenting results from past and ongoing research focused on understanding the causes and consequences of tundra burning in the past, present, and future. The talk will integrate several lines of work, including reconstructing tundra fire history in the recent and distant past (2000-14,000 yr), quantifying relationships among modern climate, vegetation, and tundra burning, and anticipating future tundra burning given future climate scenarios.
J. R. Marlon, P. J. Bartlein, D. G. Gavin, C. J. Long, R. S. Anderson, C. E. Briles, K. J. Brown, D. Colombaroli, D. J. Hallett, M. J. Power, E. A. Scharf, M. K. Walsh. PNAS Plus: Long-term perspective on wildfires in the western USA. Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1112839109
Here’s a big Thank You to everyone who attended last week’s webinar “Once burned, twice shy”, presented on Feb. 23rd. For those who could not attend or who have been eagerly awaiting the follow up materials, please feel free to explore the videos, documents and links below. (For more information, see our previous post on this webinar.)
A re-burned fire with little to no black spruce regeneration, 2007. Photo courtesy of C. Brown.
Dr. Carissa Brown, Postdoctoral Researcher at the University of Sherbrooke, will be joining us for a webinar on February 23, 2012 (11:00 am to noon AKST) entitled “Once burned, twice shy: Repeat fires result in black spruce regeneration failure.” Dr. Brown is currently studying plant species and communities at the edge of their range, focusing on the direct and indirect effects of climate change on species distribution at northern latitudes. Most recently, her work has focused on the responses to altered fire frequency at the northern margin of the boreal forest, particularly in black spruce forests.
Can’t seem to stay up to date? Let us do some of the work.
We’ve put together a bibliography of November’s (plus or minus a few weeks) new fire science publications related to Alaska and the boreal forest. Download a simple bibliography or an annotated version, both in a pdf format including URLs for each reference. Just want the highlights? We showcased a few of our “Top Picks” below.
Werth, Paul A.; Potter, Brian E.; Clements, Craig B.; Finney, Mark A.; Goodrick, Scott L.; Alexander, Martin E.; Cruz, Miguel G.; Forthofer, Jason A.; McAllister, Sara S. 2011. Synthesis of knowledge of extreme fire behavior: volume I for fire managers. Gen. Tech. Rep. PNW-GTR-854. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 144 p.
Watch this new video on Climate and Fire in Alaska, featuring Dr. Scott Rupp, UAF Professor, and Jennifer Barnes, NPS Fire Ecologist!
This video is 1 of a 5 part video series entitledClimate Change Watch (produced by Frontier Scientists and Wonder Visions). The Climate Change Watch series includes the following videos: Classrooms for Climate, Changing Biomes (In Production), Hydrology (In Production), Permafrost (In Production), and Fire in Alaska.