Relationships between moisture, chemistry, and ignition of Pinus contorta needles during the early stages of mountain pine beetle attack

Jolly, W. Matt; Parsons, Russell A.; Hadlow, Ann M.; Cohn, Greg; McAllister, Sara; Popp, John B.; Hubbard, Robert M.; Negrón, José F.

doi:10.1016/j.foreco.2011.12.022

Cited by 126 publications

(93 citation statements)

References 26 publications

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“…That this effect was only detected under extreme conditions is consistent with the importance of hot, dry, windy conditions for sustaining fire in large-diameter dead fuels from beetle-killed trees (15,30). Our data also suggested a decline in canopy fuels remaining after fire with increasing outbreak severity, which could reflect the intermix of red and green canopy fuels (14,15,21,29) and increased flammability of needles in recently attacked trees (21,29), possibly leading to greater consumption of nearby needles on trees that were live at the time of fire. However, support for this effect was moderate (Fig.…”

Section: Discussionmentioning

confidence: 65%

“…Such variation allowed us to assess fire severity across the spectrum of recent prefire outbreak severity, including stands unaffected by the recent outbreaks (effectively serving as a control). Three fires burned forests where most attacked stands were in the red postoutbreak stage (0-2 y after beetle attack, ∼50% retention of largely red needles on beetle-killed trees) (12,14,15), considered to be most vulnerable to increased crown fire because canopy fuels are drier and more flammable (21,29). Three fires burned forests where most attacked stands were in the gray postoutbreak stage (3-10 y after beetle attack, <5% needle retention on beetle-killed trees, most beetle-killed trees still standing) (12,14,15).…”

Section: Significancementioning

confidence: 99%

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Recent mountain pine beetle outbreaks, wildfire severity, and postfire tree regeneration in the US Northern Rockies

Harvey

Donato

Turner

2014

Proc. Natl. Acad. Sci. U.S.A.

122

123

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Widespread tree mortality caused by outbreaks of native bark beetles (Circulionidae: Scolytinae) in recent decades has raised concern among scientists and forest managers about whether beetle outbreaks fuel more ecologically severe forest fires and impair postfire resilience. To investigate this question, we collected extensive field data following multiple fires that burned subalpine forests in 2011 throughout the Northern Rocky Mountains across a spectrum of prefire beetle outbreak severity, primarily from mountain pine beetle (Dendroctonus ponderosae). We found that recent (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010) beetle outbreak severity was unrelated to most field measures of subsequent fire severity, which was instead driven primarily by extreme burning conditions (weather) and topography. In the red stage (0-2 y following beetle outbreak), fire severity was largely unaffected by prefire outbreak severity with few effects detected only under extreme burning conditions. In the gray stage (3-10 y following beetle outbreak), fire severity was largely unaffected by prefire outbreak severity under moderate conditions, but several measures related to surface fire severity increased with outbreak severity under extreme conditions. Initial postfire tree regeneration of the primary beetle host tree [lodgepole pine (Pinus contorta var. latifolia)] was not directly affected by prefire outbreak severity but was instead driven by the presence of a canopy seedbank and by fire severity. Recent beetle outbreaks in subalpine forests affected few measures of wildfire severity and did not hinder the ability of lodgepole pine forests to regenerate after fire, suggesting that resilience in subalpine forests is not necessarily impaired by recent mountain pine beetle outbreaks. disturbance interactions | forest resilience | fire ecology | serotiny | conifer forest

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Section: Discussionmentioning

confidence: 65%

Section: Significancementioning

confidence: 99%

Recent mountain pine beetle outbreaks, wildfire severity, and postfire tree regeneration in the US Northern Rockies

Harvey

Donato

Turner

2014

Proc. Natl. Acad. Sci. U.S.A.

122

123

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“…Moreover, the fuel profile such as surface, ladder, and crown fuels are expected to change with time since outbreak, potentially altering fire behavior and fire risk. After tree death, needles fade to red within a year of attack (red stage) and risks of ignition, torching, and canopy fire are expected to increase due to lower leaf moisture content (10 times lower in foliar moisture content compared to green needles), non-fiber carbohydrates and fats, which increase flammability [83,84]. Approximately 3 to 10 years (gray stage) after the beetle attack, trees drop their needles and twigs and become exposed in the upper crown [81], which likely increases the forest floor fuels [81,82].…”

Section: Forest Firementioning

confidence: 99%

Aftermath of Mountain Pine Beetle Outbreak in British Columbia: Stand Dynamics, Management Response and Ecosystem Resilience

Dhar

Parrott

Hawkins

2016

Forests

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Abstract:The mountain pine beetle (Dendroctonus ponderosae Hopkins) (MPB) has infested and killed millions of hectares of lodgepole pine (Pinus contorta var. latifolia Engelm) forests in British Columbia, Canada, over the past decade. It is now spreading out of its native range into the Canadian boreal forest, with unknown social, economic and ecological consequences. This review explores the ramifications of the MPB epidemic with respect to mid-term timber supply, forest growth, structure and composition, vegetation diversity, forest fire, climate change, and ecosystem resilience. Research confirms that, in British Columbia, all of these variables are more significantly impacted when salvage logging is used as management response to the outbreak. We conclude that appropriate management in response to MPB is essential to ensuring ecologically resilient future forests and reliable mid-term timber supplies for affected human communities. We highlight knowledge gaps and avenues for research to advance our understanding in support of sustainable post-disturbance forest management policies in British Columbia and elsewhere.

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“…We simulated each level of mortality for both the red and the gray phases, to account for temporal changes in the fuel complex, by modifying fuel mass and moisture distribution in FIRETEC input data. For red-phase simulations, killed trees retained their entire pre-outbreak biomass, but with a reduced canopy fuel moisture of 15 %, which falls within the range for recently killed lodgepole pine needles (Jolly et al 2012). For grayphase simulations, the canopy biomass of killed trees was "transferred" from crowns to the surface fuel to mimic the fall of dead canopy fuel.…”

Section: Firetec Simulation Fuel Beds Setupmentioning

confidence: 88%

“…Lower fuel moisture levels during the red phase are critical to alter the threshold required for crown ignition (Jolly et al 2012, Giunta et al 2016 and transition from the surface into the canopy. For example, dead red-phase lodgepole pine (Pinus contorta Douglas ex Loudon) needles averaged ~12 % moisture content compared to green needles that averaged ~109 % moisture content; and dead needles ignited up to four times faster than green needles in laboratory ignition tests (Jolly et al 2012). At low wind speeds and low mortality levels, this effect results in the torching of dead trees, but has only minimal effect on consumption of live trees.…”

Section: Discussionmentioning

confidence: 99%

Untitled

2017

Fire Ecology

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Previous studies have suggested that bark beetles and fires can be interacting disturbances, whereby bark beetlecaused tree mortality can alter the risk and severity of subsequent wildland fires. However, there remains considerable uncertainty around the type and magnitude of the interaction between fires following bark beetle attacks, especially in drier forest types such as those dominated by ponderosa pine (Pinus ponderosa Lawson & C. Lawson). We used a full factorial design across a range of factors thought to control bark beetle−fire interactions, including the temporal phase of the RESUMENEstudios previos han sugerido que los escarabajos de la corteza y el fuego pueden ser disturbios interactivos, por lo que la mortalidad de árboles causada por estos escarabajos puede alterar el riesgo y la severidad de incendios subsecuentes. Sin embargo, una considerable incertidumbre persiste en torno al tipo y magnitud de la interacción entre los incendios que siguen al ataque de insectos, especialmente en tipos de bosques secos como los dominados por pino ponderosa (Pinus ponderosa Lawson & C. Lawson). Usamos un diseño factorial a través de un rango de factores que pensamos controlaban la interacción entre el escarabajo de la corteza y los incendios, incluyendo la fase temporal del estallido del insecto, el nivel Fire Ecology Volume 13, Issue 3, 2017 doi: 10.4996/fireecology.130300123 Sieg et al.: Bark Beetle-Fire Disturbance Interactions Page 2 outbreak, level of mortality, and wind speed. We used a three-dimensional physics-based model, HIGRAD/FIRE-TEC, to simulate fire behavior in fuel beds representative of 60 field plots across five national forests in northern Arizona, USA. The plots were dominated by ponderosa pine, and encompassed a gradient of bark beetlecaused mortality due to a mixture of both Ips and Dendroctonus species. Non-host species included two sprouting species, Gambel oak (Quercus gambelii Nutt.) and alligator juniper (Juniperus deppeana Steud.), as well as other junipers and pinyon pine (Pinus edulis Engelm.). The simulations explicitly accounted for the modifications of fuel mass and moisture distribution caused by bark beetle-caused mortality. We first analyzed the influence of the outbreak phase, level of mortality, and wind speed on the severity of a subsequent fire, expressed as a function of live and dead canopy fuel consumption. We then computed a metric based on canopy fuel loss to characterize whether bark beetles and fire are linked disturbances and, if they are, if the linkage is antagonistic (net bark beetle and fire severity being less than if the two disturbances occurred independently) or synergistic (greater combined effects than independent disturbances). Both the severity of a subsequent fire and whether bark beetles and fire are linked disturbances depended on the outbreak phase of the bark beetle mortality and attack severity, as well as the fire weather (here, wind). Greater fire severity and synergistic interactions were generally associated with the "red phase"...

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Relationships between moisture, chemistry, and ignition of Pinus contorta needles during the early stages of mountain pine beetle attack

Cited by 126 publications

References 26 publications

Recent mountain pine beetle outbreaks, wildfire severity, and postfire tree regeneration in the US Northern Rockies

Recent mountain pine beetle outbreaks, wildfire severity, and postfire tree regeneration in the US Northern Rockies

Aftermath of Mountain Pine Beetle Outbreak in British Columbia: Stand Dynamics, Management Response and Ecosystem Resilience

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