Award Abstract # 1736778
Collaborative Research: Regional impacts of increasing fire frequency on carbon dynamics and species composition in the boreal forest

NSF Org: OPP
Office of Polar Programs (OPP)
Recipient: UNIVERSITY OF FLORIDA
Initial Amendment Date: July 25, 2017
Latest Amendment Date: June 8, 2018
Award Number: 1736778
Award Instrument: Standard Grant
Program Manager: Rainer Amon
OPP
 Office of Polar Programs (OPP)
GEO
 Directorate for Geosciences
Start Date: January 1, 2018
End Date: December 31, 2021 (Estimated)
Total Intended Award Amount: $315,993.00
Total Awarded Amount to Date: $326,828.00
Funds Obligated to Date: FY 2017 = $315,993.00
FY 2018 = $10,835.00
History of Investigator:
  • Jason Vogel (Principal Investigator)
    jason09vogel@gmail.com
Recipient Sponsored Research Office: University of Florida
1523 UNION RD RM 207
GAINESVILLE
FL  US  32611-1941
(352)392-3516
Sponsor Congressional District: 03
Primary Place of Performance: University of Florida
P.O. Box 110410
Gainesville
FL  US  32611-0410
Primary Place of Performance
Congressional District:
03
Unique Entity Identifier (UEI): NNFQH1JAPEP3
Parent UEI:
NSF Program(s): ANS-Arctic Natural Sciences
Primary Program Source: 0100XXXXDB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s): 1079, 9251
Program Element Code(s): 528000
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.078

ABSTRACT

The Arctic is warming faster than any other area of the world and its boreal forests have experienced dramatic increases in the size and frequency of fires. The fast pace of these changes has prompted concern because boreal forests make up about a third of all forests worldwide, contain almost half of the world's stored carbon, and have been historically stable with black spruce dominating this landscape for the past 6,000 years. Warming of 2-8 °C is projected by the end of the century and the emergence of a new fire regime threatens to disrupt this forest ecosystem. For example, in some regions of interior Alaska, the fire return interval has decreased to 10-50 years, causing shifts from black spruce to deciduous trees and grasses. Changes in the climate and fire regime are also expected to affect global carbon cycling since fires and thawing of frozen soils (permafrost) may release large amounts of carbon into the atmosphere. This research will incorporate field studies and computer simulations to determine how fire frequency and climate change affect shifts between vegetation types (e.g. switch from conifer to grasses) and long term carbon storage in this vast and under-studied region. The study will train graduate students and involve Native American high school students from the Rural Alaska Honors Institute (RAHI) in field work. The investigators will collaborate with Your World Rocks (YWR), a nonprofit organization of female scientists and engineers dedicated to promoting science education in elementary schools. They will develop hands-on activities focusing on climate change, forests, and fire and conduct free hands-on activities in elementary schools in the greater Portland/Vancouver metro area, with a particular focus on underserved Title 1 schools.

The fast pace of climate warming and an increase in fire frequency over the past few decades in northern latitudes has raised concerns about major shifts in vegetation and the long-term ability of ecosystems to capture and store carbon. Boreal forest ecosystems account for about 33% of all forests worldwide and contain about 45% of the world's carbon stocks, with the majority (~85%) stored belowground. For the past 6,000 years, black spruce (Picea mariana (Mill.) B.S.P.) has been the dominant species over a large proportion of this landscape, exhibiting substantial resilience to changes in climate. However, unprecedented warming (causing earlier snowmelt, permafrost thawing, and longer growing seasons) and the emergence of a new fire regime over the past 60 years threatens to disrupt the existing dominance by black spruce and release globally significant amounts of carbon into the atmosphere. The goal of this research is to quantify the potential for large-scale changes in carbon (C) sink strength, C stocks, and vegetation in boreal forests due to climate change and repeated wildfires by integrating mechanistic field and lab work with dynamic, spatially explicit landscape modeling. Working in central Alaska, the investigators will: 1) determine how fire frequency and climate change affect successional trajectories and above- and belowground C cycling, and 2) assess how the mechanisms that cause tipping points between vegetation types (i.e. conifer, hardwood, graminoid) and C sequestration (i.e. sink, source) vary spatially and temporally. To achieve these objectives, the investiagors will empirically measure above- and belowground C stocks, productivity, heterotrophic respiration, soil temperature and moisture content, and active layer thickness in the field and quantify C mineralization using laboratory soil incubations. They will also develop and validate a physically based permafrost/hydrology module for a widely-used, high resolution landscape simulation model (LANDIS-II) to forecast long-term dynamics of species composition and C source/sink status given projected changes in climate (including thawing permafrost) and fire. The work will improve our understanding of how C cycling and species composition in boreal forests will respond to climate change and disturbances at the fine spatial scales critical to accurately project the future of the boreal forest.

PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH

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Shabaga, Jason A. and Bracho, Rosvel and Klockow, Paul A. and Lucash, Melissa S. and Vogel, Jason G. "Shortened Fire Intervals Stimulate Carbon Losses from Heterotrophic Respiration and Reduce Understorey Plant Productivity in Boreal Forests" Ecosystems , v.26 , 2022 https://doi.org/10.1007/s10021-022-00761-w Citation Details

PROJECT OUTCOMES REPORT

Disclaimer

This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

Catastrophic wildfires in the northern boreal forest typically occur in intervals of 100-200 years. In the period between burns, vegetation regrowth contributes to a buildup of carbon in the surface and mineral soils, which removes carbon from the atmosphere as carbon dioxide (CO2), a potent ‘greenhouse’ gas. The carbon that accumulates at the surface is called the organic layer, which helps to insulate the soil and contributes to the formation of permafrost (ground that is frozen for over two years). The permafrost helps capture carbon in the soil by slowing down the rate that microorganisms consume organic matter, similar to preventing food from rotting in a freezer. Throughout many burn cycles, tremendous amounts of carbon deposits have built up in the permafrost soils of northern regions. If these soils are warmed, it is predicted that microorganisms will increase how quickly they convert soil carbon into CO2.  

Because of ongoing climate change, some scientists using computer models predict that wildfires will occur more frequently in the boreal forest, decreasing the interval of fire occurrence to 20-50 years. This increased burning will warm soil temperatures, potentially slowing the accumulation of carbon in the soil down between fire cycles. More concerning, the previously stored carbon could be released into the atmosphere because of increased activity by soil microorganisms. Either of these changes would increase the potential impacts of climate change associated with the buildup of CO2.

We examined whether shorter intervals between wildfires would cause an increase in the loss of soil carbon as CO2 from a common boreal ecosystem. In our study, the shortened return of fire (20-50 years) corresponded to the increased release of CO2 due to the increased activity of microbes consuming organic carbon in the soil. This CO2 release corresponded both to an increase in soil temperature at depths where permafrost normally occurred and to a shift in vegetation type away from spruce to deciduous trees. The change in vegetation type might reflect a change in the microorganisms found in the soil or in how they function. Increased burn frequency also reduced the effectiveness of ground-level vegetation in the removal of CO2 from the atmosphere during photosynthesis. Reduced photosynthesis could further slow the rate of soil carbon accumulation. These results suggest that an increase in burn frequency will reduce the amount of soil carbon found in the boreal forest, potentially exacerbating the effects of climate change by increasing the buildup of atmospheric CO2.    

 


Last Modified: 05/16/2022
Modified by: Jason Vogel

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