Landscape-scale changes in canopy fuels and potential fire behaviour following ponderosa pine restoration treatments

2008 ◽  
Vol 17 (2) ◽  
pp. 293 ◽  
Author(s):  
John P. Roccaforte ◽  
Peter Z. Fulé ◽  
W. Wallace Covington
Keyword(s):  
Ponderosa Pine ◽  
Landscape Scale ◽  
Fuel Load ◽  
Permanent Plots ◽  
Crown Fire ◽  
Fire Behaviour ◽  
Treated Area ◽  
Canopy Fuels ◽  
Behaviour Changes ◽  
Historical Forest

We evaluated canopy fuels and potential fire behaviour changes following landscape-scale restoration treatments in a ponderosa pine forest at Mt Trumbull, Arizona, USA. The goal of the project was to restore historical forest structure by thinning and burning, thereby reducing canopy fuels and minimising active crown fire potential. We measured 117 permanent plots before (1996–97) and after (2003) treatments. The plots were evenly distributed across the landscape and represented an area of ~1200 ha, about half of which was an untreated control. We compared canopy fuel estimates using three different methods to assess whether fire behaviour modelling outputs were sensitive to the choice of canopy fuel equation. Treatments decreased canopy fuel load by 43–50% from 0.77–1.83 kg m–2 to 0.44–0.91 kg m–2 (the range of values reflects the different canopy fuel equations) and decreased canopy bulk density by 42–61% from 0.038–0.172 kg m–3 to 0.022–0.067 kg m–3 in the treated area, while slight increases occurred in the control. We applied two fire models to estimate potential fire behaviour: FlamMap and NEXUS. These models differ in several important features but predicted outcomes were consistent: under extreme drought and wind conditions, the proportion of the landscape susceptible to active crown fire decreased in the treated area while little change occurred in the control.

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.

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.

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.

scholarly journals Utah juniper and two-needle piñon reduction alters fuel loads

2015 ◽  
Vol 24 (2) ◽  
pp. 236 ◽  
Author(s):  
Kert R. Young ◽  
Bruce A. Roundy ◽  
Stephen C. Bunting ◽  
Dennis L. Eggett
Keyword(s):  
Block Design ◽  
Tree Cover ◽  
Fuel Load ◽  
Fire Intensity ◽  
Crown Fire ◽  
Understorey Vegetation ◽  
Fuel Loads ◽  
Canopy Fuels ◽  
Utah Juniper ◽  
Pinus Spp

Juniper (Juniperus spp.) and piñon (Pinus spp.) trees have encroached millions of hectares of sagebrush (Artemisia spp.)–bunchgrass communities. Juniper–piñon trees are treated to reduce canopy fuel loads and crown fire potential. We measured the effects of juniper–piñon infilling and fuel-reduction treatments on fuel load characteristics at four locations in Utah. At each location, treatment areas were burned, left untreated, or trees were cut or masticated in a randomised complete-block design. We measured standing and downed fuels by size and type along 30-m transects on 15 subplots (30 × 33 m) per location before and 1–3 years after treatment. Increased tree cover was associated with decreased shrub and herbaceous fuel loads (P < 0.01). By 2 years post-treatment, herbaceous fuel loads were greater than pretreatment in all treated areas (P < 0.01). Cut and mastication treatments increased surface woody 10- and 100-h fuel loads and wood/bark cover (P < 0.01). Masticated-tree depth was a good estimator of fuel loads (R2 = 92). The conversion of canopy fuels to surface fuels reduced fuels that enable crown fire and extreme fire intensity. Cool-season prescribed fire may need to follow mechanical treatments to reduce surface fuel and the potential for wildfire damage to perennial understorey vegetation.

scholarly journals Estimación de la distribución vertical de combustibles finos del dosel de copas en masas de Pinus sylvestris empleando datos LiDAR de baja densidad

2019 ◽  
pp. 1 ◽  
Author(s):  
L. A. Fidalgo-González ◽  
S. Arellano-Pérez ◽  
J. G. Álvarez-González ◽  
F. Castedo-Dorado ◽  
A. D. Ruiz-González ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Fire Hazard ◽  
National Forest Inventory ◽  
Fuel Load ◽  
Crown Fire ◽  
Cross Model ◽  
Canopy Fuels ◽  
Structural Variables ◽  
Fire Initiation ◽  
Using Data

<p>Canopy fuel load, canopy bulk density and canopy base height are structural variables used to predict crown fire initiation and spread. Direct measurement of these variables is not functional, and they are usually estimated indirectly by modelling. Advances in fire behaviour modelling require accurate and landscape scale estimates of the complete vertical distribution of canopy fuels. The goal of the present study is to model the vertical profile of available canopy fuels in Scots pine stands by using data from the Spanish national forest inventory and low-density LiDAR data (0.5 first returns  m<sup>–2</sup>) provided by Spanish PNOA project (Plan Nacional de Ortofotografía Aérea). In a first step, the vertical distribution of the canopy fuel load was modelled using the Weibull probability density function. In a second step, a system of models was fitted to relate the canopy variables to Lidar-derived metrics. Models were fitted simultaneously to compensate the effects of the inherent cross-model correlation between errors. Heteroscedasticity was also analyzed, but correction in the fitting process was not necessary. The estimated canopy fuel load profiles from LiDAR-derived metrics explained 41% of the variation in canopy fuel load in the analysed plots. The proposed models can be used to assess the effectiveness of different forest management alternatives for reducing crown fire hazard.</p>

Estimating canopy fuel characteristics in five conifer stands in the western United States using tree and stand measurements

2006 ◽  
Vol 36 (11) ◽  
pp. 2803-2814 ◽  
Author(s):  
Elizabeth Reinhardt ◽  
Joe Scott ◽  
Kathy Gray ◽  
Robert Keane
Keyword(s):  
Tree Height ◽  
Fuel Load ◽  
Computational Techniques ◽  
Crown Fire ◽  
Canopy Fuels ◽  
Adjustment Factors ◽  
Fuel Characteristics ◽  
Crown Base Height ◽  
Interior West ◽  
The Vertical Distribution

Assessment of crown fire potential requires quantification of canopy fuels. In this study, canopy fuels were measured destructively on plots in five Interior West conifer stands. Observed canopy bulk density, canopy fuel load, and vertical profiles of canopy fuels are compared with those estimated from stand data using several computational techniques. An allometric approach to estimating these canopy fuel characteristics was useful, but, for accuracy, estimates of vertical biomass distribution and site-adjustment factors were required. Available crown fuel was estimated separately for each tree according to species, diameter, and crown class. The vertical distribution of this fuel was then modeled within each tree crown on the basis of tree height and crown base height. Summing across trees within the stand at every height yielded an estimated vertical profile of canopy fuel that approximated the observed distribution.

scholarly journals A comparison of charcoal reflectance between crown and surface fire contexts in dry south-west USA forests

2018 ◽  
Vol 27 (6) ◽  
pp. 396 ◽  
Author(s):  
Christopher I. Roos ◽  
Andrew C. Scott
Keyword(s):  
Ponderosa Pine ◽  
Fire Severity ◽  
Prescribed Fires ◽  
Crown Fire ◽  
Fire Behaviour ◽  
Surface Fire ◽  
Surface Fires ◽  
South West ◽  
Crown Fires ◽  
Mixed Conifer Forests

The historical and modern importance of crown fires in ponderosa pine and dry mixed-conifer forests of the south-west USA has been much debated. The microscopic reflectance of charcoal in polished blocks under oil shows promise as a semiquantitative proxy for fire severity using charcoal from post-fire landscapes. We measured the reflectance of 33 modern charcoal samples to evaluate (1) whether charcoal reflectance can distinguish between crown fires and surface fires in these forests; and (2) whether surface fires with masticated fuels burn with severities similar to surface fires in grass, litter and duff fuels. The charcoal analysed was primarily collected after wildland fires under two different conditions: (l) wildfires with moderate to high severity and crown fire behaviour (n = 17), and (2) prescribed fires with low to moderate severity but no crown fire behaviour (n = 16). Statistical analysis indicates that charcoal reflectance produced in crown fires significantly differs from surface fire charcoal, particularly surface fire charcoal formed in grass, duff and litter fuels. However, charcoal produced from surface fires in masticated fuels is indistinguishable from crown fire charcoal, suggesting that fires in areas that have experienced in situ mastication may have soil impacts similar to crown fires.

Fuel and fire characteristics in savanna - woodland of West Africa in relation to grazing and dominant grass type

2007 ◽  
Vol 16 (5) ◽  
pp. 531 ◽  
Author(s):  
Patrice Savadogo ◽  
Didier Zida ◽  
Louis Sawadogo ◽  
Daniel Tiveau ◽  
Mulualem Tigabu ◽  
...  
Keyword(s):  
Prescribed Burning ◽  
Management Tool ◽  
Fuel Load ◽  
Maximum Temperature ◽  
Fire Intensity ◽  
Fire Behaviour ◽  
Savanna Woodland ◽  
Vegetation Height ◽  
Average Maximum ◽  
Dominant Grass

Fuel characteristics, fire behaviour and temperature were studied in relation to grazing, dominant grass type and wind direction in West African savanna–woodland by lighting 32 prescribed early fires. Grazing significantly reduced the vegetation height, total fuel load, and dead and live fuel fractions whereas plots dominated by perennial grasses had higher values for vegetation height, total fuel load and the quantity of live fuel load. Although fire intensity remained insensitive (P > 0.05) to any of these factors, fuel consumption was significantly (P = 0.021) reduced by grazing, rate of spread was faster in head fire (P = 0.012), and flame length was shorter in head fire than back fire (P = 0.044). The average maximum temperature was higher (P < 0.05) on non-grazed plots, on plots dominated by annual grasses, on plots subjected to head fire, and at the soil surface. Lethal temperature residence time showed a nearly similar trend to fire temperature. Wind speed and total fuel load were best predictors of fire behaviour parameters (R2 ranging from 0.557 to 0.862). It can be concluded that grazing could be used as a management tool to modify fire behaviour, back fire should be carried out during prescribed burning to lower fire severity, and the fire behaviour models can be employed to guide prescribed early fire in the study area.

Characterizing Canopy Fuels to Predict Fire Behavior in Pitch Pine Stands

2007 ◽  
Vol 24 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Matthew J. Duveneck ◽  
William A. Patterson
Keyword(s):  
Fire Behavior ◽  
Small Diameter ◽  
Basal Area ◽  
Regression Equations ◽  
Crown Fire ◽  
Pinus Rigida ◽  
Canopy Fuels ◽  
Pitch Pine ◽  
Thinning Operations ◽  
Pine Stands

Abstract Destructive sampling of 31 pitch pine (Pinus rigida P. Mill) trees ranging in dbh from 2.7 to 42.5 cm and in height from 4.1 to 23.8 m provided a complete inventory of needles and small-diameter branch weights used to characterize canopy fuels to predict fire behavior in pitch pine stands. Regression equations using dbh as an independent variable predict canopy bulk density with an r2 > 0.93. The results provide managers with a method of evaluating the effectiveness of thinning operations in reducing crown fire potential in well-stocked stands. To demonstrate the application of the method, we calculated the wind speed (Crowning Index [CI]) needed to sustain an active crown fire in thinned and unthinned pitch pine stands in Montague, Massachusetts. Thinning to 2.8 m2/ha basal area increased the CI from 34 to 98 km/hour.

Modelling the rate of fire spread and uncertainty associated with the onset and propagation of crown fires in conifer forest stands

2017 ◽  
Vol 26 (5) ◽  
pp. 413 ◽  
Author(s):  
Miguel G. Cruz ◽  
Martin E. Alexander
Keyword(s):  
Monte Carlo ◽  
Average Rate ◽  
Fire Spread ◽  
Prediction Errors ◽  
Crown Fire ◽  
Conifer Forest ◽  
Fire Behaviour ◽  
Crown Fires ◽  
Deterministic Modelling ◽  
Eastern Australia

Crown fires are complex, unstable phenomena dependent on feedback mechanisms between the combustion products of distinct fuel layers. We describe non-linear fire behaviour associated with crowning and the uncertainty they cause in fire behaviour predictions by running a semiphysical modelling system within a simple Monte Carlo simulation framework. The method was able to capture the dynamics of passive and active crown fire spread regimes, providing estimates of average rate of spread and the extent of crown fire activity. System outputs were evaluated against data collected from a wildfire that occurred in a radiata pine plantation in south-eastern Australia. The Monte Carlo method reduced prediction errors relative to the more commonly used deterministic modelling approach, and allowed a more complete description of the level of crown fire behaviour to expect. The method also provides uncertainty measures and probabilistic outputs, extending the range of questions that can be answered by fire behaviour models.

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