Simulated fire behaviour in young, postfire lodgepole pine forests

2017 ◽  
Vol 26 (10) ◽  
pp. 852 ◽  
Author(s):  
Kellen N. Nelson ◽  
Monica G. Turner ◽  
William H. Romme ◽  
Daniel B. Tinker
Keyword(s):  
Pinus Contorta ◽  
Stand Structure ◽  
Lodgepole Pine ◽  
Pine Forests ◽  
Fuel Moisture ◽  
Crown Fire ◽  
Fire Behaviour ◽  
Fire Initiation ◽  
Moisture Conditions ◽  
Simulated Fire

Early-seral forests are expanding throughout western North America as fire frequency and annual area burned increase, yet fire behaviour in young postfire forests is poorly understood. We simulated fire behaviour in 24-year-old lodgepole pine (Pinus contorta var. latifolia) stands in Yellowstone National Park, Wyoming, United States using operational models parameterised with empirical fuel characteristics, 50–99% fuel moisture conditions, and 1–60kmhr−1 open winds to address two questions: [1] How does fireline intensity, and crown fire initiation and spread vary among young, lodgepole pine stands? [2] What are the contributions of fuels, moisture and wind on fire behaviour? Sensitivity analysis indicated the greatest contributors to output variance were stand structure mediated wind attenuation, shrub fuel loads and 1000-h fuel moisture for fireline intensity; crown base height for crown fire initiation; and crown bulk density and 1-h fuel moisture for crown fire spread. Simulation results predicted crown fire (e.g. passive, conditional or active types) in over 90% of stands at 50th percentile moisture conditions and wind speeds greater than 3kmhr−1. We conclude that dense canopy characteristics heighten crown fire potential in young, postfire lodgepole pine forests even under less than extreme wind and fuel moisture conditions.

scholarly journals Firefighter Observations of “Surprising” Fire Behavior in Mountain Pine Beetle-Attacked Lodgepole Pine Forests

Fire ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 34 ◽  
Author(s):  
Kevin Moriarty ◽  
Antony S. Cheng ◽  
Chad M. Hoffman ◽  
Stuart P. Cottrell ◽  
Martin E. Alexander
Keyword(s):  
Mountain Pine Beetle ◽  
Lodgepole Pine ◽  
Fire Behavior ◽  
Pine Forests ◽  
Fuel Moisture ◽  
Crown Fire ◽  
Gray Phase ◽  
Mountain Pine ◽  
Pine Beetle ◽  
Moisture Conditions

The recent mountain pine beetle outbreak affecting lodgepole pine forests in the Rocky Mountains has created a novel fire environment for wildland firefighters. This paper presents results from an examination of firefighters’ observations of fire behavior in post-outbreak lodgepole pine forests, with a focus on what they considered surprising from a fire behavior standpoint and how this in turn affected their suppression tactics. The surprises in fire behavior experienced by firefighters during the red phase of post-outbreak forests included an elevated level of fire spread and intensity under moderate weather and fuel moisture conditions, increased spotting, and faster surface-to-crown fire transitions with limited or no ladder fuels. Unexpectedly, during the gray phase in mountain pine beetle-attacked stands, crown ignition and crown fire propagation was observed for short periods of time. Firefighters are now more likely to expect to see active fire behavior in nearly all fire weather and fuel moisture conditions, not just under critically dry and windy situations, and across all mountain pine beetle attack phases, not just the red phase. Firefighters changed their suppression tactics by adopting indirect methods due to the potential fire behavior and tree-fall hazards associated with mountain pine beetle-attacked lodgepole pine forests.

scholarly journals Evaluating the 3-m tree crown spacing guideline for the prevention of crowning wildfires in lodgepole pine forests, Alberta

2020 ◽  
Vol 96 (02) ◽  
pp. 165-173
Author(s):  
Martin E. Alexander ◽  
Miguel G. Cruz
Keyword(s):  
Bulk Density ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Pine Forests ◽  
Crown Fire ◽  
Conifer Forest ◽  
Fire Propagation ◽  
Current State ◽  
General Recommendation ◽  
Canopy Bulk Density

A 3-m between crown spacing is a commonly cited criterion found in the wildland-urban interface fire literature for minimizing the likelihood of a fully-developed crown fire from occurring in a conifer forest on level terrain. The validity of this general recommendation is examined here in light of our current state-of-knowledge regarding crown fire propagation in relation to canopy bulk density. Given the characteristics of the overstory structure for 20 lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) stands located in Alberta, as sourced from the literature, the canopy fuel properties following a virtual thinning to a 3-m crown spacing and then to a targeted canopy bulk density of 0.05 kg/m3 were computed. On the basis of these computations, crown fire potential was then analyzed and interpreted. The conclusion reached is that, in the majority of cases, a less widely spaced stand would be adequate for preventing crown fire development in lodgepole pine forests.

Wildfire’s resistance to control in mountain pine beetle-attacked lodgepole pine forests

2013 ◽  
Vol 89 (06) ◽  
pp. 783-794 ◽  
Author(s):  
Wesley G. Page ◽  
Martin E. Alexander ◽  
Michael J. Jenkins
Keyword(s):  
Pinus Contorta ◽  
Mountain Pine Beetle ◽  
Tree Mortality ◽  
Lodgepole Pine ◽  
Wildland Fire ◽  
Fire Suppression ◽  
Pine Forests ◽  
Fire Behaviour ◽  
Mountain Pine ◽  
Pine Beetle

Concerns about the impacts of mountain pine beetle (Dendroctonus ponderosae Hopkins)-caused tree mortality on wildfire potential in lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) forests have to date largely focused on the potential for extreme fire behaviour, including the development and spread of crown fires. Given that the wildland fire environment in which fire managers and firefighters work is composed of many interacting physical and human factors, viewing crown fire behaviour as the only or even the most important outcome of the tree mortality associated with a mountain pine beetle outbreak is questionable. Proper assessment of wildfire potential entails a broader approach, which requires expanding the concept of wildfire resistance to control to include an analysis of all relevant factors and their interactions. In this paper we describe a holistic concept of analyzing the impacts of mountain pine beetle-caused tree mortality on wildfire potential in lodgepole pine forests on the basis of fire behaviour characteristics, fire suppression operations, and firefighter safety considerations within the framework of three recognizable stages of the approximate time since the initiation of an outbreak (i.e., “red” ∼1 to 5 years, “gray” ∼5 to 15 years, and post-epidemic ∼15+ years).

Forest structure altered by mountain pine beetle outbreaks affects subsequent attack in a Wyoming lodgepole pine forest, USA

2011 ◽  
Vol 41 (12) ◽  
pp. 2403-2412 ◽  
Author(s):  
Daniel M. Kashian ◽  
Rebecca M. Jackson ◽  
Heather D. Lyons
Keyword(s):  
Pinus Contorta ◽  
Mountain Pine Beetle ◽  
Stand Structure ◽  
Lodgepole Pine ◽  
Climate Change Scenarios ◽  
Cone Production ◽  
Mountain Pine ◽  
Large Trees ◽  
Pine Beetle ◽  
The 1960S

Extensive outbreaks of the mountain pine beetle ( Dendroctonus ponderosae Hopkins) will alter the structure of many stands that will likely be attacked again before experiencing a stand-replacing fire. We examined a stand of lodgepole pine ( Pinus contorta var. latifolia Engelm. ex S. Watson) in Grand Teton National Park currently experiencing a moderate-level outbreak and previously attacked by mountain pine beetle in the 1960s. Consistent with published studies, tree diameter was the main predictor of beetle attack on a given tree, large trees were preferentially attacked, and tree vigor, age, and cone production were unimportant variables for beetle attack at epidemic levels. Small trees killed in the stand were killed based mainly on their proximity to large trees and were likely spatially aggregated with large trees as a result of the previous outbreak. We concluded that the driving factors of beetle attack and their spatial patterns are consistent across outbreak severities but that stand structure altered by the previous outbreak had implications for the current outbreaks in the same location. This study should catalyze additional research that examines how beetle-altered stand structure affects future outbreaks — an important priority for predicting their impacts under climate change scenarios that project increases in outbreak frequency and extent.

scholarly journals Do mountain pine beetle outbreaks change the probability of active crown fire in lodgepole pine forests?

2011 ◽  
Vol 81 (1) ◽  
pp. 3-24 ◽  
Author(s):  
Martin Simard ◽  
William H. Romme ◽  
Jacob M. Griffin ◽  
Monica G. Turner
Keyword(s):  
Mountain Pine Beetle ◽  
Lodgepole Pine ◽  
Pine Forests ◽  
Crown Fire ◽  
Mountain Pine ◽  
Pine Beetle

scholarly journals A Possible Role for Red Squirrels in Structuring Breeding Bird Communities in Lodgepole Pine Forests

The Condor ◽  
2006 ◽  
Vol 108 (1) ◽  
pp. 232-238 ◽  
Author(s):  
Adam M. Siepielski
Keyword(s):  
Nest Predation ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Bird Communities ◽  
Pine Forests ◽  
Tamiasciurus Hudsonicus ◽  
Breeding Bird ◽  
Bird Abundance ◽  
Red Squirrels ◽  
Cavity Nesters

Abstract Nest predation is thought to play an important role in structuring certain breeding bird communities. One potential consequence of nest predation is lower recruitment in breeding birds, which may be manifested as lower breeding bird abundance. Lodgepole pine (Pinus contorta ssp. latifolia) forests east and west of the Rocky Mountains became isolated following glacial retreat 12 000 years ago and differ in whether or not red squirrels (Tamiasciurus hudsonicus), which are a key nest predator, are present. Breeding bird abundance in lodgepole pine forests was compared between four ranges with red squirrels and four ranges without red squirrels. Species grouped into canopy and understory nesting guilds were, on average, two and three times more abundant, respectively, in forest ranges without red squirrels than in ranges with red squirrels; no statistically significant differences were found for midstory, ground, or cavity nesters. These results suggest that geographic variation in the presence or absence of red squirrels is likely important in structuring breeding bird communities in lodgepole pine forests across the landscape.

Effect of thinning and prescribed burning on crown fire severity in ponderosa pine forests

2002 ◽  
Vol 11 (1) ◽  
pp. 1 ◽  
Author(s):  
Jolie Pollet ◽  
Philip N. Omi
Keyword(s):  
Prescribed Fire ◽  
Ponderosa Pine ◽  
Stand Structure ◽  
Fire Severity ◽  
Fire Effects ◽  
Pine Forests ◽  
Crown Fire ◽  
Fuel Treatments ◽  
Ponderosa Pine Forests ◽  
Wildfire Hazard

Fire exclusion policies have affected stand structure and wildfire hazard in north American ponderosa pine forests. Wildfires are becoming more severe in stands where trees are densely stocked with shade-tolerant understory trees. Although forest managers have been employing fuel treatment techniques to reduce wildfire hazard for decades, little scientific evidence documents the success of treatments in reducing fire severity. Our research quantitatively examined fire effects in treated and untreated stands in western United States national forests. Four ponderosa pine sites in Montana, Washington, California and Arizona were selected for study. Fuel treatments studied include: prescribed fire only, whole-tree thinning, and thinning followed by prescribed fire. On-the-ground fire effects were measured in adjacent treated and untreated forests. We developed post facto fire severity and stand structure measurement techniques to complete field data collection. We found that crown fire severity was mitigated in stands that had some type of fuel treatment compared to stands without any treatment. At all four of the sites, the fire severity and crown scorch were significantly lower at the treated sites. Results from this research indicate that fuel treatments, which remove small diameter trees, may be beneficial for reducing crown fire hazard in ponderosa pine sites.

Long-term responses of mammalian herbivores to stand thinning and fertilization in young lodgepole pine (Pinus contorta var. latifolia) forest

2010 ◽  
Vol 40 (12) ◽  
pp. 2302-2312 ◽  
Author(s):  
Thomas P. Sullivan ◽  
Druscilla S. Sullivan ◽  
Pontus M.F. Lindgren ◽  
Douglas B. Ransome
Keyword(s):  
Habitat Use ◽  
Pinus Contorta ◽  
Large Scale ◽  
Stand Structure ◽  
Lodgepole Pine ◽  
South Central ◽  
Commercial Thinning ◽  
Snowshoe Hares ◽  
Understory Shrubs

Snowshoe hares (Lepus americanus Exrleben, 1777), mule deer (Odocoileus hemionus (Rafinesque, 1817)), and moose (Alces alces (L., 1758)) commonly occur in young coniferous forests. This study was designed to test the hypothesis that large-scale pre-commercial thinning (PCT) and repeated fertilization 15–20 years after the onset of treatments in young lodgepole pine (Pinus contorta var. latifolia Engelm. ex S. Wats.) stands would enhance relative habitat use by hares, deer, and moose compared with unmanaged stands. Study areas were located in south-central British Columbia, Canada. Habitat use was measured by fecal pellet and pellet-group counts. Understory vegetation and coniferous stand structure were measured in all stands. Habitat use by deer and moose was highest in heavily thinned stands, probably due to the higher levels of forage and cover provided by understory shrubs and conifers in thinned stands. Habitat use by snowshoe hares was highest in high-density stands, but also in lower-density (≤1000 stems·ha–1) stands where an increase in understory conifers provided essential cover for hares. Managers should consider the long-term nature of understory development in young stands managed for timber production. Heavy thinning (≤1000 stems·ha–1) will generate suitable understory habitat for these herbivores sooner than conventional PCT at higher stand densities.

scholarly journals Numerical Simulation of Crown Fire Hazard Immediately after Bark Beetle-Caused Mortality in Lodgepole Pine Forests

2012 ◽  
Vol 58 (2) ◽  
pp. 178-188 ◽  
Author(s):  
Chad Hoffman ◽  
Penelope Morgan ◽  
William Mell ◽  
Russell Parsons ◽  
Eva K. Strand ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Bark Beetle ◽  
Lodgepole Pine ◽  
Fire Hazard ◽  
Pine Forests ◽  
Crown Fire

scholarly journals Assessment of crown fire initiation and spread models in Mediterranean conifer forests by using data from field and laboratory experiments

2017 ◽  
Vol 26 (2) ◽  
pp. e02S ◽  
Author(s):  
Francisco Rodríguez y Silva ◽  
Mercedes Guijarro ◽  
Javier Madrigal ◽  
Enrique Jiménez ◽  
Juan R. Molina ◽  
...  
Keyword(s):  
Fire Spread ◽  
Full Scale ◽  
Research Centre ◽  
Crown Fire ◽  
Fire Behaviour ◽  
Bench Scale ◽  
Fire Experiment ◽  
Fire Initiation ◽  
Scale Experiment

Aims of study: To conduct the first full-scale crown fire experiment carried out in a Mediterranean conifer stand in Spain; to use different data sources to assess crown fire initiation and spread models, and to evaluate the role of convection in crown fire initiation.Area of study: The Sierra Morena mountains (Coordinates ETRS89 30N: X: 284793-285038; Y: 4218650-4218766), southern Spain, and the outdoor facilities of the Lourizán Forest Research Centre, northwestern Spain.Material and methods: The full-scale crown fire experiment was conducted in a young Pinus pinea stand. Field data were compared with data predicted using the most used crown fire spread models. A small-scale experiment was developed with Pinus pinaster trees to evaluate the role of convection in crown fire initiation. Mass loss calorimeter tests were conducted with P. pinea needles to estimate residence time of the flame, which was used to validate the crown fire spread model.Main results: The commonly used crown fire models underestimated the crown fire spread rate observed in the full-scale experiment, but the proposed new integrated approach yielded better fits. Without wind-forced convection, tree crowns did not ignite until flames from an intense surface fire contacted tree foliage. Bench-scale tests based on radiation heat flux therefore offer a limited insight to full-scale phenomena.Research highlights: Existing crown fire behaviour models may underestimate the rate of spread of crown fires in many Mediterranean ecosystems. New bench-scale methods based on flame buoyancy and more crown field experiments allowing detailed measurements of fire behaviour are needed.

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