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

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.

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Simulated fire behaviour in young, postfire lodgepole pine forests

International Journal of Wildland Fire ◽

10.1071/wf16226 ◽

2017 ◽

Vol 26 (10) ◽

pp. 852 ◽

Cited By ~ 9

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.

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Flatland in flames: a two-dimensional crown fire propagation model

International Journal of Wildland Fire ◽

10.1071/wf07107 ◽

2009 ◽

Vol 18 (5) ◽

pp. 527 ◽

Cited By ~ 3

Author(s):

James D. Dickinson ◽

Andrew P. Robinson ◽

Paul E. Gessler ◽

Richy J. Harrod ◽

Alistair M. S. Smith

Keyword(s):

Bulk Density ◽

Original Data ◽

Propagation Model ◽

Crown Fire ◽

Wagner Model ◽

Fire Propagation ◽

Rate Of Spread ◽

Proposed Model ◽

Foliar Biomass ◽

Canopy Bulk Density

The canopy bulk density metric is used to describe the fuel available for combustion in crown fire models. We propose modifying the Van Wagner crown fire propagation model, used to estimate the critical rate of spread necessary to sustain active crown fire, to use foliar biomass per square metre instead of canopy bulk density as the fuel input. We tested the efficacy of our proposed model by comparing predictions of crown fire propagation with Van Wagner’s original data. Our proposed model correctly predicted each instance of crown fire presented in the seminal study. We then tested the proposed model for statistical equivalence to the original Van Wagner model using two contemporary techniques to parameterize canopy bulk density. We found the proposed and original models to be statistically equivalent when canopy bulk density was parameterized using the method incorporated in the Fire and Fuels Extension to the Forest Vegetation Simulator (difference < 0.5 km h–1, α = 0.05, n = 2626), but not when parameterized using the method of Cruz and others. Use of foliar biomass per unit area in the proposed model makes for more accurate and easily obtained fuel estimates without sacrificing the utility of the Van Wagner model.

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Development and testing of models for predicting crown fire rate of spread in conifer forest stands

Canadian Journal of Forest Research ◽

10.1139/x05-085 ◽

2005 ◽

Vol 35 (7) ◽

pp. 1626-1639 ◽

Cited By ~ 97

Author(s):

Miguel G Cruz ◽

Martin E Alexander ◽

Ronald H Wakimoto

Keyword(s):

Bulk Density ◽

Fire Behavior ◽

Fire Regimes ◽

Management Decision ◽

Crown Fire ◽

Conifer Forest ◽

Data Set ◽

Rate Of Spread ◽

Spread Model ◽

Canopy Bulk Density

The rate of spread of crown fires advancing over level to gently undulating terrain was modeled through nonlinear regression analysis based on an experimental data set pertaining primarily to boreal forest fuel types. The data set covered a significant spectrum of fuel complex and fire behavior characteristics. Crown fire rate of spread was modeled separately for fires spreading in active and passive crown fire regimes. The active crown fire rate of spread model encompassing the effects of 10-m open wind speed, estimated fine fuel moisture content, and canopy bulk density explained 61% of the variability in the data set. Passive crown fire spread was modeled through a correction factor based on a criterion for active crowning related to canopy bulk density. The models were evaluated against independent data sets originating from experimental fires. The active crown fire rate of spread model predicted 42% of the independent experimental crown fire data with an error lower then 25% and a mean absolute percent error of 26%. While the models have some shortcomings and areas in need of improvement, they can be readily utilized in support of fire management decision making and other fire research studies.

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

Ecological Monographs ◽

10.1890/10-1176.1 ◽

2011 ◽

Vol 81 (1) ◽

pp. 3-24 ◽

Cited By ~ 178

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

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Estimating canopy fuel characteristics for predicting crown fire potential in common forest types of the Atlantic Coastal Plain, USA

International Journal of Wildland Fire ◽

10.1071/wf18025 ◽

2018 ◽

Vol 27 (11) ◽

pp. 742 ◽

Cited By ~ 1

Author(s):

Anne G. Andreu ◽

John I. Blake ◽

Stanley J. Zarnoch

Keyword(s):

Bulk Density ◽

Coastal Plain ◽

Canopy Cover ◽

Atlantic Coastal Plain ◽

Theoretic Approach ◽

Crown Fire ◽

Prescribed Burns ◽

Stand Height ◽

Atlantic Coastal ◽

Canopy Bulk Density

We computed four stand-level canopy stratum variables important for crown fire modelling – canopy cover, stand height, canopy base height and canopy bulk density – from forest inventory data. We modelled the relationship between the canopy variables and a set of common inventory parameters – site index, stem density, basal area, stand age or stand height – and number of prescribed burns. We used a logistic model to estimate canopy cover, a linear model to estimate the other canopy variables, and the information theoretic approach for model selection. Coefficients of determination across five forest groups were 0.72–0.91 for stand height, 0.36–0.83 for canopy base height, 0.39–0.80 for canopy cover, and 0.63–0.78 for canopy bulk density. We assessed crown fire potential (1) for several sets of environmental conditions in all seasons, and (2) with increasing age, density and number of prescribed burns using our modelled canopy bulk density and canopy base height variables and local weather data to populate the Crown Fire Initiation and Spread model. Results indicated that passive crown fire is possible in any season in Atlantic coastal plain pine stands with heavy surface fuel loads and active crown fire is most probable in infrequently burned, dense stands at low fuel moistures.

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

The Condor ◽

10.1093/condor/108.1.232 ◽

2006 ◽

Vol 108 (1) ◽

pp. 232-238 ◽

Cited By ~ 1

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.

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

Forest Science ◽

10.5849/forsci.10-137 ◽

2012 ◽

Vol 58 (2) ◽

pp. 178-188 ◽

Cited By ~ 36

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

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Canopy bulk density and canopy base height equations for assessing crown fire hazard in Pinus radiata plantations

Canadian Journal of Forest Research ◽

10.1139/x10-237 ◽

2011 ◽

Vol 41 (4) ◽

pp. 839-850 ◽

Cited By ~ 16

Author(s):

Ana Daría Ruiz-González ◽

Juan Gabriel Álvarez-González

Keyword(s):

Bulk Density ◽

Pinus Radiata ◽

Fire Hazard ◽

Direct Action ◽

Quantitative Information ◽

Wildlife Habitat ◽

Vertical Profiles ◽

Crown Fire ◽

Crown Fires ◽

Canopy Bulk Density

Crown fires combine high rates of spread, flame lengths, and intensities, making it virtually impossible to control them by direct action and having significant impact on soils, vegetation, and wildlife habitat. For these reasons, fire managers have great interest in preventive silviculture of forested landscapes to avoid the initiation and propagation of crown fires. The minimum conditions necessary to initiate and propagate crown fires are assumed to be strongly influenced by the stand structural variables canopy bulk density (CBD) and canopy base height (CBH). However, there is a lack of quantitative information on these variables and how to estimate them. To characterize the aerial fuel layers of Pinus radiata D. Don, the vertical profiles of canopy fuel in 180 sample plots of pure and even-aged P. radiata plantations were analysed. Effective CBD and CBH were obtained from the vertical profiles, and equations relating these variables to common stand variables were fitted simultaneously. Inclusion of the fitted equations in existing dynamic growth models, together with the use of current fire behaviour and hazard prediction tools, will provide a decision support system for assessing the crown fire potential of different silvicultural alternatives for this species.

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

Fire ◽

10.3390/fire2020034 ◽

2019 ◽

Vol 2 (2) ◽

pp. 34 ◽

Cited By ~ 8

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.

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