Evaluating regression model estimates of canopy fuel stratum characteristics in four crown fire-prone fuel types in western North America

2012 ◽  
Vol 21 (2) ◽  
pp. 168 ◽  
Author(s):  
Miguel G. Cruz ◽  
Martin E. Alexander
Keyword(s):  
North America ◽  
Bulk Density ◽  
Ponderosa Pine ◽  
Stand Structure ◽  
Coniferous Forest ◽  
Fuel Load ◽  
Regression Equations ◽  
Western North America ◽  
Crown Fire ◽  
Canopy Bulk Density

Two evaluations were undertaken of the regression equations developed by M. Cruz, M. Alexander and R. Wakimoto (2003, International Journal of Wildland Fire 12, 39–50) for estimating canopy fuel stratum characteristics from stand structure variables for four broad coniferous forest fuel types found in western North America. The first evaluation involved a random selection of 10 stands each from the four datasets used in the original study. These were in turn subjected to two simulated thinning regimes (i.e. 25 and 50% basal area removal). The second evaluation involved a completely independent dataset for ponderosa pine consisting of 16 stands sampled by T. Keyser and F. Smith (2010, Forest Science 56, 156–165). Evaluation statistics were comparable for the thinning scenarios and independent evaluations. Mean absolute percentage errors varied between 13.8 and 41.3% for canopy base height, 5.3 and 67.9% for canopy fuel load, and 20.7 and 71% for canopy bulk density. Bias errors were negligible. The results of both evaluations clearly show that the stand-level models of Cruz et al. (2003) used for estimating canopy base height, canopy fuel load and canopy bulk density in the assessment of crown fire potential are, considering their simplicity, quite robust.

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

2018 ◽  
Vol 27 (11) ◽  
pp. 742 ◽  
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.

Corrigendum to: Assessing canopy fuel stratum characteristics in crown fire prone fuel types of western North America

2010 ◽  
Vol 19 (1) ◽  
pp. iii ◽  
Author(s):  
Miguel G. Cruz ◽  
Martin E. Alexander ◽  
Ronald H. Wakimoto
Keyword(s):  
Ponderosa Pine ◽  
Fire Management ◽  
Linear Regression Analysis ◽  
Basal Area ◽  
Stand Density ◽  
Fuel Load ◽  
Tree Level ◽  
Management Decision ◽  
Crown Fire ◽  
In Fire

Application of crown fire behavior models in fire management decision-making have been limited by the difficulty of quantitatively describing fuel complexes, specifically characteristics of the canopy fuel stratum. To estimate canopy fuel stratum characteristics of four broad fuel types found in the western United States and adjacent areas of Canada, namely Douglas-fir, ponderosa pine, mixed conifer, and lodgepole pine forest stands, data from the USDA Forest Service's Forest Inventory and Analysis (FIA) database were analysed and linked with tree-level foliage dry weight equations. Models to predict canopy base height (CBH), canopy fuel load (CFL) and canopy bulk density (CBD) were developed through linear regression analysis and using common stand descriptors (e.g. stand density, basal area, stand height) as explanatory variables. The models developed were fuel type specific and coefficients of determination ranged from 0.90 to 0.95 for CFL, between 0.84 and 0.92 for CBD and from 0.64 to 0.88 for CBH. Although not formally evaluated, the models seem to give a reasonable characterization of the canopy fuel stratum for use in fire management applications.

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.

scholarly journals Assessing canopy fuel stratum characteristics in crown fire prone fuel types of western North America

2003 ◽  
Vol 12 (1) ◽  
pp. 39 ◽  
Author(s):  
Miguel G. Cruz ◽  
Martin E. Alexander ◽  
Ronald H. Wakimoto
Keyword(s):  
Ponderosa Pine ◽  
Fire Management ◽  
Linear Regression Analysis ◽  
Basal Area ◽  
Stand Density ◽  
Fuel Load ◽  
Tree Level ◽  
Management Decision ◽  
Crown Fire ◽  
In Fire

Application of crown fire behavior models in fire management decision-making have been limited by the difficulty of quantitatively describing fuel complexes, specifically characteristics of the canopy fuel stratum. To estimate canopy fuel stratum characteristics of four broad fuel types found in the western United States and adjacent areas of Canada, namely Douglas-fir, ponderosa pine, mixed conifer, and lodgepole pine forest stands, data from the USDA Forest Service's Forest Inventory and Analysis (FIA) database were analysed and linked with tree-level foliage dry weight equations. Models to predict canopy base height (CBH), canopy fuel load (CFL) and canopy bulk density (CBD) were developed through linear regression analysis and using common stand descriptors (e.g. stand density, basal area, stand height) as explanatory variables. The models developed were fuel type specific and coefficients of determination ranged from 0.90 to 0.95 for CFL, between 0.84 and 0.92 for CBD and from 0.64 to 0.88 for CBH. Although not formally evaluated, the models seem to give a reasonable characterization of the canopy fuel stratum for use in fire management applications.

Forest fuel treatments in western North America: Merging silviculture and fire management

2005 ◽  
Vol 81 (3) ◽  
pp. 365-368 ◽  
Author(s):  
Morris C Johnson ◽  
David L Peterson
Keyword(s):  
North America ◽  
Fire Management ◽  
Stand Structure ◽  
Fire Hazard ◽  
Spatial Scales ◽  
Fire Disturbance ◽  
Western North America ◽  
Fire Behaviour ◽  
Fuel Treatments ◽  
Management Tools

For many years silviculture and fire management have mostly been separate forestry disciplines with disparate objectives and activities. However, in order to accomplish complex and multiple management objectives related to forest structure, fuels, and fire disturbance, these two disciplines must be effectively integrated in science and practice. We have linked scientific and management tools to develop an analytical approach that allows resource managers to quantify and evaluate the effectiveness of alternative fuel treatments in dry interior forests of western North America. The principal tool is the Fire and Fuels Extension of the Forest Vegetation Simulator (FFE-FVS) for characterizing fuel succession and fire behaviour, and for quantifying and visualizing stand structure. FFE-FVS provides a user-friendly framework that facilitates rapid evaluation of thinning and surface fuel treatments intended to reduce crown fire potential and fireline intensity. This approach quantifies fire hazard at small and large spatial scales, assists with treatment priorities and schedules, and generates stand and landscape visualizations that facilitate decisions about appropriate fuel treatments. Key words: fire behaviour, fire hazard, fuel treatments, silviculture

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

2011 ◽  
Vol 41 (4) ◽  
pp. 839-850 ◽  
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.

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.

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

2009 ◽  
Vol 18 (5) ◽  
pp. 527 ◽  
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.

scholarly journals Average Stand Age from Forest Inventory Plots Does Not Describe Historical Fire Regimes in Ponderosa Pine and Mixed-Conifer Forests of Western North America

PLoS ONE ◽  
2016 ◽  
Vol 11 (5) ◽  
pp. e0147688 ◽  
Author(s):  
Jens T. Stevens ◽  
Hugh D. Safford ◽  
Malcolm P. North ◽  
Jeremy S. Fried ◽  
Andrew N. Gray ◽  
...  
Keyword(s):  
North America ◽  
Ponderosa Pine ◽  
Forest Inventory ◽  
Fire Regimes ◽  
Stand Age ◽  
Western North America ◽  
Conifer Forests ◽  
Mixed Conifer ◽  
Mixed Conifer Forests

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

2005 ◽  
Vol 35 (7) ◽  
pp. 1626-1639 ◽  
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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