Impacts of pre-fire conifer density and wildfire severity on ecosystem structure and function at the forest-tundra ecotone
Wildfire frequency and extent is increasing throughout the boreal forest-tundra ecotone as climate warms. Understanding the impacts of wildfire throughout this ecotone is required to make predictions of the rate and magnitude of changes in boreal-tundra landcover, its future flammability, and associ...
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crplos:10.1371/journal.pone.0258558 2024-09-15T17:35:38+00:00 Impacts of pre-fire conifer density and wildfire severity on ecosystem structure and function at the forest-tundra ecotone Walker, Xanthe J. Howard, Brain K. Jean, Mélanie Johnstone, Jill F. Roland, Carl Rogers, Brendan M. Schuur, Edward A. G. Solvik, Kylen K. Mack, Michelle C. Hui, Dafeng National Aeronautics and Space Administration National Science Foundation 2021 http://dx.doi.org/10.1371/journal.pone.0258558 https://dx.plos.org/10.1371/journal.pone.0258558 en eng Public Library of Science (PLoS) https://creativecommons.org/publicdomain/zero/1.0/ PLOS ONE volume 16, issue 10, page e0258558 ISSN 1932-6203 journal-article 2021 crplos https://doi.org/10.1371/journal.pone.0258558 2024-09-03T04:14:01Z Wildfire frequency and extent is increasing throughout the boreal forest-tundra ecotone as climate warms. Understanding the impacts of wildfire throughout this ecotone is required to make predictions of the rate and magnitude of changes in boreal-tundra landcover, its future flammability, and associated feedbacks to the global carbon (C) cycle and climate. We studied 48 sites spanning a gradient from tundra to low-density spruce stands that were burned in an extensive 2013 wildfire on the north slope of the Alaska Range in Denali National Park and Preserve, central Alaska. We assessed wildfire severity and C emissions, and determined the impacts of severity on understory vegetation composition, conifer tree recruitment, and active layer thickness (ALT). We also assessed conifer seed rain and used a seeding experiment to determine factors controlling post-fire tree regeneration. We found that an average of 2.18 ± 1.13 Kg C m -2 was emitted from this fire, almost 95% of which came from burning of the organic soil. On average, burn depth of the organic soil was 10.6 ± 4.5 cm and both burn depth and total C combusted increased with pre-fire conifer density. Sites with higher pre-fire conifer density were also located at warmer and drier landscape positions and associated with increased ALT post-fire, greater changes in pre- and post-fire understory vegetation communities, and higher post-fire boreal tree recruitment. Our seed rain observations and seeding experiment indicate that the recruitment potential of conifer trees is limited by seed availability in this forest-tundra ecotone. We conclude that the expected climate-induced forest infilling (i.e. increased density) at the forest-tundra ecotone could increase fire severity, but this infilling is unlikely to occur without increases in the availability of viable seed. Article in Journal/Newspaper alaska range north slope Tundra Alaska PLOS PLOS ONE 16 10 e0258558 |
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English |
description |
Wildfire frequency and extent is increasing throughout the boreal forest-tundra ecotone as climate warms. Understanding the impacts of wildfire throughout this ecotone is required to make predictions of the rate and magnitude of changes in boreal-tundra landcover, its future flammability, and associated feedbacks to the global carbon (C) cycle and climate. We studied 48 sites spanning a gradient from tundra to low-density spruce stands that were burned in an extensive 2013 wildfire on the north slope of the Alaska Range in Denali National Park and Preserve, central Alaska. We assessed wildfire severity and C emissions, and determined the impacts of severity on understory vegetation composition, conifer tree recruitment, and active layer thickness (ALT). We also assessed conifer seed rain and used a seeding experiment to determine factors controlling post-fire tree regeneration. We found that an average of 2.18 ± 1.13 Kg C m -2 was emitted from this fire, almost 95% of which came from burning of the organic soil. On average, burn depth of the organic soil was 10.6 ± 4.5 cm and both burn depth and total C combusted increased with pre-fire conifer density. Sites with higher pre-fire conifer density were also located at warmer and drier landscape positions and associated with increased ALT post-fire, greater changes in pre- and post-fire understory vegetation communities, and higher post-fire boreal tree recruitment. Our seed rain observations and seeding experiment indicate that the recruitment potential of conifer trees is limited by seed availability in this forest-tundra ecotone. We conclude that the expected climate-induced forest infilling (i.e. increased density) at the forest-tundra ecotone could increase fire severity, but this infilling is unlikely to occur without increases in the availability of viable seed. |
author2 |
Hui, Dafeng National Aeronautics and Space Administration National Science Foundation |
format |
Article in Journal/Newspaper |
author |
Walker, Xanthe J. Howard, Brain K. Jean, Mélanie Johnstone, Jill F. Roland, Carl Rogers, Brendan M. Schuur, Edward A. G. Solvik, Kylen K. Mack, Michelle C. |
spellingShingle |
Walker, Xanthe J. Howard, Brain K. Jean, Mélanie Johnstone, Jill F. Roland, Carl Rogers, Brendan M. Schuur, Edward A. G. Solvik, Kylen K. Mack, Michelle C. Impacts of pre-fire conifer density and wildfire severity on ecosystem structure and function at the forest-tundra ecotone |
author_facet |
Walker, Xanthe J. Howard, Brain K. Jean, Mélanie Johnstone, Jill F. Roland, Carl Rogers, Brendan M. Schuur, Edward A. G. Solvik, Kylen K. Mack, Michelle C. |
author_sort |
Walker, Xanthe J. |
title |
Impacts of pre-fire conifer density and wildfire severity on ecosystem structure and function at the forest-tundra ecotone |
title_short |
Impacts of pre-fire conifer density and wildfire severity on ecosystem structure and function at the forest-tundra ecotone |
title_full |
Impacts of pre-fire conifer density and wildfire severity on ecosystem structure and function at the forest-tundra ecotone |
title_fullStr |
Impacts of pre-fire conifer density and wildfire severity on ecosystem structure and function at the forest-tundra ecotone |
title_full_unstemmed |
Impacts of pre-fire conifer density and wildfire severity on ecosystem structure and function at the forest-tundra ecotone |
title_sort |
impacts of pre-fire conifer density and wildfire severity on ecosystem structure and function at the forest-tundra ecotone |
publisher |
Public Library of Science (PLoS) |
publishDate |
2021 |
url |
http://dx.doi.org/10.1371/journal.pone.0258558 https://dx.plos.org/10.1371/journal.pone.0258558 |
genre |
alaska range north slope Tundra Alaska |
genre_facet |
alaska range north slope Tundra Alaska |
op_source |
PLOS ONE volume 16, issue 10, page e0258558 ISSN 1932-6203 |
op_rights |
https://creativecommons.org/publicdomain/zero/1.0/ |
op_doi |
https://doi.org/10.1371/journal.pone.0258558 |
container_title |
PLOS ONE |
container_volume |
16 |
container_issue |
10 |
container_start_page |
e0258558 |
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1810469979729952768 |