Effects of mountain pine beetle on fuels and expected fire behavior in lodgepole pine forests, Colorado, USA.

In Colorado and southern Wyoming, mountain pine beetle (MPB) has affected over 1.6 million ha of predominantly lodgepole pine forests, raising concerns about effects of MPB-caused mortality on subsequent wildfire risk and behavior. Using empirical data we modeled potential fire behavior across a gra...

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Main Authors: Tania Schoennagel, Thomas T Veblen, José F Negron, Jeremy M Smith
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2012-01-01
Series:PLoS ONE
Online Access:https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/22272268/pdf/?tool=EBI
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author Tania Schoennagel
Thomas T Veblen
José F Negron
Jeremy M Smith
author_facet Tania Schoennagel
Thomas T Veblen
José F Negron
Jeremy M Smith
author_sort Tania Schoennagel
collection DOAJ
description In Colorado and southern Wyoming, mountain pine beetle (MPB) has affected over 1.6 million ha of predominantly lodgepole pine forests, raising concerns about effects of MPB-caused mortality on subsequent wildfire risk and behavior. Using empirical data we modeled potential fire behavior across a gradient of wind speeds and moisture scenarios in Green stands compared three stages since MPB attack (Red [1-3 yrs], Grey [4-10 yrs], and Old-MPB [∼30 yrs]). MPB killed 50% of the trees and 70% of the basal area in Red and Grey stages. Across moisture scenarios, canopy fuel moisture was one-third lower in Red and Grey stages compared to the Green stage, making active crown fire possible at lower wind speeds and less extreme moisture conditions. More-open canopies and high loads of large surface fuels due to treefall in Grey and Old-MPB stages significantly increased surface fireline intensities, facilitating active crown fire at lower wind speeds (>30-55 km/hr) across all moisture scenarios. Not accounting for low foliar moistures in Red and Grey stages, and large surface fuels in Grey and Old-MPB stages, underestimates the occurrence of active crown fire. Under extreme burning conditions, minimum wind speeds for active crown fire were 25-35 km/hr lower for Red, Grey and Old-MPB stands compared to Green. However, if transition to crown fire occurs (outside the stand, or within the stand via ladder fuels or wind gusts >65 km/hr), active crown fire would be sustained at similar wind speeds, suggesting observed fire behavior may not be qualitatively different among MPB stages under extreme burning conditions. Overall, the risk (probability) of active crown fire appears elevated in MPB-affected stands, but the predominant fire hazard (crown fire) is similar across MPB stages and is characteristic of lodgepole pine forests where extremely dry, gusty weather conditions are key factors in determining fire behavior.
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spelling doaj.art-b16b1942c823418c9d8bc28df9b1dea72022-12-21T19:27:38ZengPublic Library of Science (PLoS)PLoS ONE1932-62032012-01-0171e3000210.1371/journal.pone.0030002Effects of mountain pine beetle on fuels and expected fire behavior in lodgepole pine forests, Colorado, USA.Tania SchoennagelThomas T VeblenJosé F NegronJeremy M SmithIn Colorado and southern Wyoming, mountain pine beetle (MPB) has affected over 1.6 million ha of predominantly lodgepole pine forests, raising concerns about effects of MPB-caused mortality on subsequent wildfire risk and behavior. Using empirical data we modeled potential fire behavior across a gradient of wind speeds and moisture scenarios in Green stands compared three stages since MPB attack (Red [1-3 yrs], Grey [4-10 yrs], and Old-MPB [∼30 yrs]). MPB killed 50% of the trees and 70% of the basal area in Red and Grey stages. Across moisture scenarios, canopy fuel moisture was one-third lower in Red and Grey stages compared to the Green stage, making active crown fire possible at lower wind speeds and less extreme moisture conditions. More-open canopies and high loads of large surface fuels due to treefall in Grey and Old-MPB stages significantly increased surface fireline intensities, facilitating active crown fire at lower wind speeds (>30-55 km/hr) across all moisture scenarios. Not accounting for low foliar moistures in Red and Grey stages, and large surface fuels in Grey and Old-MPB stages, underestimates the occurrence of active crown fire. Under extreme burning conditions, minimum wind speeds for active crown fire were 25-35 km/hr lower for Red, Grey and Old-MPB stands compared to Green. However, if transition to crown fire occurs (outside the stand, or within the stand via ladder fuels or wind gusts >65 km/hr), active crown fire would be sustained at similar wind speeds, suggesting observed fire behavior may not be qualitatively different among MPB stages under extreme burning conditions. Overall, the risk (probability) of active crown fire appears elevated in MPB-affected stands, but the predominant fire hazard (crown fire) is similar across MPB stages and is characteristic of lodgepole pine forests where extremely dry, gusty weather conditions are key factors in determining fire behavior.https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/22272268/pdf/?tool=EBI
spellingShingle Tania Schoennagel
Thomas T Veblen
José F Negron
Jeremy M Smith
Effects of mountain pine beetle on fuels and expected fire behavior in lodgepole pine forests, Colorado, USA.
PLoS ONE
title Effects of mountain pine beetle on fuels and expected fire behavior in lodgepole pine forests, Colorado, USA.
title_full Effects of mountain pine beetle on fuels and expected fire behavior in lodgepole pine forests, Colorado, USA.
title_fullStr Effects of mountain pine beetle on fuels and expected fire behavior in lodgepole pine forests, Colorado, USA.
title_full_unstemmed Effects of mountain pine beetle on fuels and expected fire behavior in lodgepole pine forests, Colorado, USA.
title_short Effects of mountain pine beetle on fuels and expected fire behavior in lodgepole pine forests, Colorado, USA.
title_sort effects of mountain pine beetle on fuels and expected fire behavior in lodgepole pine forests colorado usa
url https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/22272268/pdf/?tool=EBI
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