Ecological Impacts of Forest Fuel Treatments in Alaska

Although vegetation treatments can reduce fire potential, they may have unintended ecological effects, but there has been little published on possible impacts—especially for Alaska. So the recent publication (Melvin, et al. 2017) of a study on interior Alaska rxbAA42_ks-sm2.jpgfuel treatments by an interdisciplinary team of researchers is an important addition to regional management resources. In fact, it probably represents the FIRST published paper specifically on how fuel-reduction affects carbon and nutrient pools, permafrost thaw, and forest successional trajectories. The analysis included 19 sites managed by numerous Alaska agencies covering a large swath from Nenana to Deltana, and were sampled at various ages from 2-12 years post-thinning or shearblading.  Our third AFSC Research Brief of 2017 is a digest of the study results.

Full Citation:  Melvin, A. M., et al. (2017), Fuel-reduction management alters plant composition, carbon and nitrogen pools, and soil thaw in Alaskan boreal forest. Ecol Appl. Accepted Author Manuscript. doi:10.1002/eap.1636

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Lightning Sparking More Boreal Forest Fires

Our Research Brief this month covers a new NASA-funded study led by Sander Veraverbeke of Vrije Universiteit  in Amsterdam which found lightning storms to be a main driver of recent large fire seasons in Alaska and Canada.  Results of the study are published in the July, 2017 issue of Nature Climate Change.

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July 2017 Nature Climate Change

MODIS (Moderate-Resolution Imaging Spectroradiometer) satellite images and data from ground-based lightning networks were employed to study fire ignitions. Sander’s analysis found increases of between two and five percent a year in the number of lightning-ignited fires since 1975. Veraverbeke said that the observed trends are consistent with climate change, with higher temperatures linked to both more burning and more thunderstorms.

Study co-author Brendan Rogers at Woods Hole Research Center in Massachusetts says these trends are likely to continue. “We expect an increasing number of thunderstorms, and hence fires, across the high latitudes in the coming decades as a result of climate change.” This is confirmed in the study by different climate model outputs.

Charles Miller of NASA’s Jet Propulsion Laboratory in California, another co-author, said while data from Alaska’s agency lightning networks were critical to this study, it is challenging to use these data to verify trends because of continuing network upgrades. “A spaceborne sensor that provides lightning data that can be linked with fire dynamics would be a major step forward,” he said. Such a sensor exists already– NASA’s spaceborne Optical Transient Detector –but it’s geostationary orbit limits its utility for high latitudes.

The researchers found that the fires are creeping farther north, near the transition from boreal forests to Arctic tundra. “In these high-latitude ecosystems, permafrost soils store large amounts of carbon that become vulnerable after fires pass through,” said co-author James Randerson of the University of California, Irvine. “Exposed mineral soils after tundra fires also provide favorable seedbeds for trees migrating north under a warmer climate.”

The Alaska Fire Science Consortium at the University of Alaska, Fairbanks, also participated in the study, and provides this 2-page Research Brief executive summary.

Citation: Veraverbeke, S., B.M. Rogers, M.L. Goulden, R.R. Jandt, C.E. Miller, E.B. Wiggins and J.T. Randerson. Lightning as a major driver of recent large fire years in North American boreal forests. Nature Climate Change 7: 529–534 (2017). DOI: 10.1038/nclimate3329

Future Fire Costs in Alaska

April Melvin of EPA’s National Climate Change Division has spent some time in the field in Alaska. In a just-released publication her research team takes a look at how firefighting costs in Alaska are likely to change through the next several decades.

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“Pumpkin” water bladder preparing burnout on the Chicken fire 2004. Photo by Cyle Wold, USFS-PNW.

They use the ALFRESCO  model developed at UAF, which simulates fire ignition and spread (annual timesteps) under different climate projections in 100-km grid cells. Read their paper (citation below) for all the details, but in a nutshell they found:  1) it’s hard to nail down precise fire cost records in the multi-jurisdictional setting!  2) Fire costs go up in the future and the biggest expenditures will be in the Full fire protection option.   3) by 2030, predicted federal fire suppression costs (not including base–support and pre-suppression) will average $27-47M annually under the RCP 4.5 (moderate emissions) climate projection. That compares to about $31M on average from 2002-2013.  Adding in state costs boosts this to about $116M total firefighting cost for Alaska assuming the state costs are still roughly 68% of the total cost.  Again this does not include base operating costs.  The paper provides some good analysis for fire protection agencies to take to the bank.  Or at least to the Legislature!

Citation: Melvin, A.M., Murray, J., Boehlert, B. et al. 2017. Estimating wildfire response costs in Alaska’s changing climate.   Climate Change:  p 1-13.  doi:10.1007/s10584-017-1923-2.

Fire’s Role in a Broadleaf Future for Alaska?

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/

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Photo by USFS, PNW (2004).

As for the second question–will it be harder for hardwoods to resist fire–a recent paper in Ecosphere (Barrett et al. 2016) is one of the first published studies to look for an answer.  AFSC highlights that work with a Research Brief this month: A Deeper Look at Drivers of Fire Activity, Re-burns, and Unburned Patches in Alaska’s Boreal Forest.  Check out all our Research Briefs in our web Library.

Citation: Barrett, K, T. Loboda, AD McGuire, H. Genet, E. Hoy, and E. Kasischke. 2016. Static and dynamic controls on fire activity at moderate spatial and temporal scales in the Alaskan boreal forest. Ecosphere 7(11):e01572. 10.1002/ecs2.1572

C.A.R.V.E. and the Carbon Detectives

How do you know whether forest fires or factories and diesel generators are responsible for Black Carbon or CO2 in the air or deposited in icefields?  An experiment called CARVE (Carbon in Arctic Reservoirs Vulnerability Experiment) led by Chip Miller of the NASA Jet Propulsion Laboratory was conducted in Alaska’s airspace and some results just published explain how the source can be identified.  The combustion of woody biomass (or more importantly in Alaska–layers of compacted dead moss and organic soil) liberates primarily carbon deposited since World War II into CO2.  That modern post-bomb carbon contains traces of radioactive  carbon (Δ14C) in contrast to fossil fuels, deposited in prehistoric times, which have none.

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CARVE:  Sherpa aircraft flew sensors over fires in Alaska in 2013 to measure atmospheric concentrations of gases.

 

 

 

 

During the CARVE experiment, Sherpa aircraft flew sensors to measure atmospheric concentrations of CH4, CO2, and CO and parameters that control gas emissions (i.e. soil moisture, freeze/thaw state, surface temperature). They directly flew over some fires (including fires near Fairbanks and Delta) to measure the “fingerprint” concentrations of isotopes released by typical boreal burning.  Mouteva et al. (2015) published findings that showed most of the C in the summer skies over Alaska in 2013 was indeed attributable to forest fires and the age of the biomass converted to black carbon averaged about 20 years (range 11-47 yrs).  The authors also explore using the carbon isotope “fingerprint” of fires to estimate the average depth of consumption–since Δ14C increases with depth from the surface moss to the mesic horizon.  Pooled results of radioactive isotope fractions yielded an average depth of burn of about 8 inches for the 2013 Alaska fires–a result that may vary depending on fuel conditions.  Burn severity, expressed as depth of consumption, is a hot topic among agencies and land managers because it drives ecological response to burning as well as vegetation changes which may come with the hypothesized climate-driven increased boreal burning.

Citation:  Mouteva, G. O., et al. (2015), Black carbon aerosol dynamics and isotopic composition in Alaska linked with boreal fire emissions and depth of burn in organic soils, Global Biogeochem. Cycles: 29, doi:10.1002/2015GB005247.

 

 

Presentations available from the CFFDRS Summit in Fairbanks!

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This presentation and MANY MORE available on fuel moisture sampling, remote sensing validation of FWI, new remote sensing tools for fire detection and growth modeling, using dataloggers on soil moisture probes to track fuel moisture changes, and the seasonality of CFFDRS, to name a few.

Whether you were there or missed it, the presentations and recorded videos from the  2014 Canadian Forest Fire Danger Rating System Summit held in Fairbanks October 28-30th are worth reviewing.  2014. The workshop was a great opportunity to discuss fire risk indices and fire behavior applications in Alaska and to hear how fire managers in Canada, the Great Lakes States and around the world are using the Canadian Forest Fire Weather Index System. There were over 50 managers and scientists in attendance.

Breakout group at the October 2014 CFFDRS Summit in Fairbanks

Breakout group at the October 2014 CFFDRS Summit in Fairbanks

Warmer Permafrost–especially in Arctic Alaska

It’s hard to say what impact the recession of permafrost in the northern half of Alaska will have on fire regime.  One could presume there should be more organic moss and duff material available for combustion during the summer, which is likely to have implications for tundra fire extent and severity.  Warmer permafrost has also been linked to more extensive retrogressive thaw slumps–a kind of thermokarst which have been seen after tundra fire in ice-rich areas (photo). If you can make it, Dr. Romanovsky’s talk “Evidence of recent warming and thawing of permafrost in the Arctic and sub-Arctic, with updates on his extensive grid of permafrost monitoring wells up and down Alaska should be very interesting.  The talk is Oct 23 at Elvey Auditorium, University of Alaska-Fairbanks, at 4 pm ADT. See the summary flyer <<HERE>>.

Photo by R. Jandt, 2010

UAF scientist Dan Mann examines fire-induced thermokarst 3 years after Anaktuvuk River fire in arctic Alaska.

Research Brief: New Satellite Sensors for Wildfire Mapping and Monitoring

UNIversity FORmation Mission 1--microsatellite designed by Hokkaido University for wildfire management (photo:  Koji Nakau)

UNIversity FORmation Mission 1–microsatellite designed by Hokkaido University for wildfire management (photo: Koji Nakau)

Hokkaido University (HU) is one of the world leaders in developing new earth-observing space technology. Dr. Koji Nakau leads their wildfire remote sensing applications team. He’s working with various partners—including UAF—on new satellite-derived products delivered to wildland fire managers in Alaska and around the world.  They are especially excited about the May 24th (2014) launch of a rocket carrying ALOS-2 (Advanced Land Observing Satellite) which is also carrying a couple microsatellites with sensors specifically designed by his team to detect wildfire signatures. In addition to improving real-time operational support, satellite data is analyzed in support of wildfire propagation modeling, smoke transport, fuels estimates, and post-fire ecology.

Read About the New Satellites>>  |  Download Research Brief PDF (744 kb)