TY - JOUR
T1 - Post-fire Recovery of Soil Organic Layer Carbon in Canadian Boreal Forests
AU - Bill, Kristen E.
AU - Dieleman, Catherine M.
AU - Baltzer, Jennifer L.
AU - Degré-Timmons, Geneviève
AU - Mack, Michelle C.
AU - Day, Nicola J.
AU - Cumming, Steve G.
AU - Walker, Xanthe J.
AU - Turetsky, Merritt R.
N1 - Funding Information:
The authors would like to acknowledge the Ka'a'gee Tu First Nation, Tłıchǫ Government, GNWT Aurora Research Institute and the Wek'éezhìi Renewable Resources Board for their support of this research. Funding was provided by NSERC Discovery Grant program, Government of the Northwest Territories Cumulative Impacts and Monitoring Project (CIMP), Government of the Northwest Territories Environmental Studies Research Fund, NASA Arctic Boreal and Vulnerability Experiment, NASA Rapid Response Grant, Canada Research Chairs Program, Polar Knowledge Canada’s Northern Science Training Program, Queen Elizabeth II Science and Technology Scholarship program, NSERC Postdoctoral Fellowship program and Rutherford Postdoctoral Fellowship from the Royal Society of New Zealand. We would like to also thank Mélina Houle for cartographic assistance.
Funding Information:
NSERC Discovery Grant (MRT); Government of the Northwest Territories Cumulative Impacts and Monitoring Project (CIMP) funding, Grant/Award number: CIMP 170 (JLB, JFJ, SGC); Government of the Northwest Territories Environmental Studies Research Fund (JLB, MRT); NASA Arctic Boreal and Vulnerability Experiment (ABoVE NASA Grant NNX15AT71A) (MCM); NASA Rapid Response Grant NNX15AD58G; Canada Research Chairs Program (JLB); Polar Knowledge Canada’s Northern Science Training Program (KEB); NSERC Postdoctoral Fellowship (NJD and CMD) and Rutherford Postdoctoral Fellowship from the Royal Society of New Zealand (NJD). We thank the GNWT Aurora Research Inst. (Research License 15879), Ka'a'gee Tu First Nation, Tłıchǫ Government and the Wek'éezhìi Renewable Resources Board for their support of this research. Crucial logistical support and laboratory space were provided by Wilfrid Laurier University—GNWT Partnership.
Publisher Copyright:
© 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
PY - 2023
Y1 - 2023
N2 - Conifer forests historically have been resilient to wildfires in part due to thick organic soil layers that regulate combustion and post-fire moisture and vegetation change. However, recent shifts in fire activity in western North America may be overwhelming these resilience mechanisms with potential impacts for energy and carbon exchange. Here, we quantify the long-term recovery of the organic soil layer and its carbon pools across 511 forested plots. Our plots span ~ 140,000 km2 across two ecozones of the Northwest Territories, Canada, and allowed us to investigate the impacts of time-after-fire, site moisture class, and dominant canopy type on soil organic layer thickness and associated carbon stocks. Despite thinner soil organic layers in xeric plots immediately after fire, these drier stands supported faster post-fire recovery of the soil organic layer than in mesic plots. Unlike xeric or mesic stands, post-fire soil carbon accumulation rates in hydric plots were negligible despite wetter forested plots having greater soil organic carbon stocks immediately post-fire compared to other stands. While permafrost and high-water tables inhibit combustion and maintain thick organic soils immediately after fire, our results suggest that these wet stands are not recovering their pre-fire carbon stocks on a century timescale. We show that canopy conversion from black spruce to jack pine or deciduous dominance could reduce organic soil carbon stocks by 60–80% depending on stand age. Our two main findings—decreasing organic soil carbon storage with increasing deciduous cover and the lack of post-fire SOL recovery in hydric sites—have implications for the turnover time of carbon stocks in the western boreal forest region and also will impact energy fluxes by controlling albedo and surface soil moisture. Graphical Abstract: [Figure not available: see fulltext.].
AB - Conifer forests historically have been resilient to wildfires in part due to thick organic soil layers that regulate combustion and post-fire moisture and vegetation change. However, recent shifts in fire activity in western North America may be overwhelming these resilience mechanisms with potential impacts for energy and carbon exchange. Here, we quantify the long-term recovery of the organic soil layer and its carbon pools across 511 forested plots. Our plots span ~ 140,000 km2 across two ecozones of the Northwest Territories, Canada, and allowed us to investigate the impacts of time-after-fire, site moisture class, and dominant canopy type on soil organic layer thickness and associated carbon stocks. Despite thinner soil organic layers in xeric plots immediately after fire, these drier stands supported faster post-fire recovery of the soil organic layer than in mesic plots. Unlike xeric or mesic stands, post-fire soil carbon accumulation rates in hydric plots were negligible despite wetter forested plots having greater soil organic carbon stocks immediately post-fire compared to other stands. While permafrost and high-water tables inhibit combustion and maintain thick organic soils immediately after fire, our results suggest that these wet stands are not recovering their pre-fire carbon stocks on a century timescale. We show that canopy conversion from black spruce to jack pine or deciduous dominance could reduce organic soil carbon stocks by 60–80% depending on stand age. Our two main findings—decreasing organic soil carbon storage with increasing deciduous cover and the lack of post-fire SOL recovery in hydric sites—have implications for the turnover time of carbon stocks in the western boreal forest region and also will impact energy fluxes by controlling albedo and surface soil moisture. Graphical Abstract: [Figure not available: see fulltext.].
KW - boreal forest resilience
KW - ecosystem carbon dynamics
KW - post-fire recovery
KW - soil organic carbon
KW - soil organic layer
KW - wildfire
UR - http://www.scopus.com/inward/record.url?scp=85162684767&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85162684767&partnerID=8YFLogxK
U2 - 10.1007/s10021-023-00854-0
DO - 10.1007/s10021-023-00854-0
M3 - Article
AN - SCOPUS:85162684767
SN - 1432-9840
JO - Ecosystems
JF - Ecosystems
ER -