scholarly journals Canopy fuel characteristics and potential crown fire behavior in Aleppo pine (Pinus halepensisMill.) forests

2007 ◽  
Vol 64 (3) ◽  
pp. 287-299 ◽  
Author(s):  
Ioannis D. Mitsopoulos ◽  
Alexandros P. Dimitrakopoulos
Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1054 ◽  
Author(s):  
Rodrigo Balaguer-Romano ◽  
Rubén Díaz-Sierra ◽  
Javier Madrigal ◽  
Jordi Voltas ◽  
Víctor Resco de Dios

Research Highlights: Pre-programmed cell death in old Aleppo pine needles leads to low moisture contents in the forest canopy in July, the time when fire activity nears its peak in the Western Mediterranean Basin. Here, we show, for the first time, that such needle senescence may increase fire behavior and thus is a potential mechanism explaining why the bulk of the annual burned area in the region occurs in early summer. Background and Objectives: The brunt of the fire season in the Western Mediterranean Basin occurs at the beginning of July, when live fuel moisture content is near its maximum. Here, we test whether a potential explanation to this conundrum lies in Aleppo pine needle senescence, a result of pre-programmed cell death in 3-years-old needles, which typically occurs in the weeks preceding the peak in the burned area. Our objective was to simulate the effects of needle senescence on fire behavior. Materials and Methods: We simulated the effects of needle senescence on canopy moisture and structure. Fire behavior was simulated across different phenological scenarios and for two highly contrasting Aleppo pine stand structures, a forest, and a shrubland. Wildfire behavior simulations were done with BehavePlus6 across a wide range of wind speeds and of dead fine surface fuel moistures. Results: The transition from surface to passive crown fire occurred at lower wind speeds under simulated needle senescence in the forest and in the shrubland. Transitions to active crown fire only occurred in the shrubland under needle senescence. Maximum fire intensity and severity were always recorded in the needle senescence scenario. Conclusions: Aleppo pine needle senescence may enhance the probability of crown fire development at the onset of the fire season, and it could partly explain the concentration of fire activity in early July in the Western Mediterranean Basin.


2011 ◽  
Vol 26 (3) ◽  
pp. 101-109 ◽  
Author(s):  
Jennifer G. Klutsch ◽  
Mike A. Battaglia ◽  
Daniel R. West ◽  
Sheryl L. Costello ◽  
José F. Negrón

Abstract A mountain pine beetle outbreak in Colorado lodgepole pine forests has altered stand and fuel characteristics that affect potential fire behavior. Using the Fire and Fuels Extension to the Forest Vegetation Simulator, potential fire behavior was modeled for uninfested and mountain pine beetle-affected plots 7 years after outbreak initiation and 10 and 80% projected tree fall using measured and projected fuel and stand characteristics. Under 90th percentile weather conditions, uninfested plots exhibited proportionally more crown fire than infested plots. Plots predicted to have crown fire were composed mainly of nonhost conifer species and had a lower and more continuous canopy than infested plots. Where surface fire was predicted to occur, live lodgepole pine was the only conifer present, and plots had significantly lower tree mortality from fire than plots predicted to have crown fire. Mountain pine beetle-induced changes in stand and fuel characteristics resulted in increased intensity of surface fire behavior. Furthermore, with 80% infested tree fall, potential smoke production was predicted to be higher. Tree species composition of stands pre and postbark beetle outbreak is important when identifying mountain pine beetle-caused changes to potential fire behavior.


2007 ◽  
Vol 24 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Matthew J. Duveneck ◽  
William A. Patterson

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.


2013 ◽  
Vol 43 (2) ◽  
pp. 149-158 ◽  
Author(s):  
Enrique Jiménez ◽  
José Antonio Vega ◽  
José María Fernández-Alonso ◽  
Daniel Vega-Nieva ◽  
Juan Gabriel Álvarez-González ◽  
...  

Adequate quantification of canopy fuel load and canopy bulk density is required for assessment of the susceptibility of forest stands to crown fire and evaluation of silvicultural treatments aimed at reducing the risk of crowning. The use of tree biomass equations and vertical profile distributions of crown fuels provide the most accurate estimates of the canopy fuel characteristics. In this study, 100 pole-size maritime pine (Pinus pinaster Aiton) trees were destructively sampled in five different sites, covering a wide range of its geographical distribution in the Iberian Peninsula. To estimate crown fuel mass, allometric equations were fitted separately for needles, twigs, and fuel available for crown fire. Models were also fitted to characterize the vertical fuel distributions as a function of tree height. All models were fitted simultaneously to guarantee additivity among tree biomass components, and corrections were also made for heterocedasticity and autocorrelation. Diameter at breast height was the best explanatory variable for all the allometric models. The vertical distribution of crown biomass fractions along tree height depended on the crown size and tree dominance. The system of equations provides a good balance between accurate predictions and low data requirements, allowing quantification of canopy fuel characteristics at stand level.


2011 ◽  
Vol 41 (5) ◽  
pp. 1018-1030 ◽  
Author(s):  
Morris C. Johnson ◽  
Maureen C. Kennedy ◽  
David L. Peterson

We used the Fire and Fuels Extension to the Forest Vegetation Simulator (FFE-FVS) to simulate fuel treatment effects on 45 162 stands in low- to midelevation dry forests (e.g., ponderosa pine ( Pinus ponderosa Dougl. ex. P. & C. Laws.) and Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) of the western United States. We evaluated treatment effects on predicted post-treatment fire behavior (fire type) and fire hazard (torching index). FFE-FVS predicts that thinning and surface fuel treatments reduced crown fire behavior relative to no treatment; a large proportion of stands were predicted to transition from active crown fire pre-treatment to surface fire post-treatment. Intense thinning treatments (125 and 250 residual trees·ha–1) were predicted to be more effective than light thinning treatments (500 and 750 residual trees·ha–1). Prescribed fire was predicted to be the most effective surface fuel treatment, whereas FFE-FVS predicted no difference between no surface fuel treatment and extraction of fuels. This inability to discriminate the effects of certain fuel treatments illuminates the consequence of a documented limitation in how FFE-FVS incorporates fuel models and we suggest improvements. The concurrence of results from modeling and empirical studies provides quantitative support for “fire-safe” principles of forest fuel reduction (sensu Agee and Skinner 2005. For. Ecol. Manag. 211: 83–96).


1993 ◽  
Vol 23 (3) ◽  
pp. 442-449 ◽  
Author(s):  
C.E. Van Wagner

Published data on two sets of experimental fires in jack pine (Pinusbanksiana Lamb.) forest were subjected to two forms of analysis. The first was a classification into surface fires and two kinds of crown fire, passive and active. In the second, the data were used to develop a model to predict both the spread rate of fire and the degree of crown consumption. The model consists mainly of two limiting equations for spread rate, one for surface fires and the other for full crowning fires; the independent variable is the Canadian Initial Spread Index. A critical surface intensity is first used to distinguish surface fires from crowning fires. A further process then estimates the degree of crowning and places the calculated final spread rate somewhere in the space between the limiting equations. The model inputs include six physical stand properties plus a pre-estimate of surface fuel consumption. It is a blend of physical theory and empirical observation.


Fire ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 34 ◽  
Author(s):  
Kevin Moriarty ◽  
Antony S. Cheng ◽  
Chad M. Hoffman ◽  
Stuart P. Cottrell ◽  
Martin E. Alexander

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.


2014 ◽  
Vol 23 (3) ◽  
pp. 350 ◽  
Author(s):  
Eduardo González-Ferreiro ◽  
Ulises Diéguez-Aranda ◽  
Felipe Crecente-Campo ◽  
Laura Barreiro-Fernández ◽  
David Miranda ◽  
...  

Crown fire initiation and spread are key elements in gauging fire behaviour potential in conifer forests. Crown fire initiation and spread models implemented in widely used fire behaviour simulation systems such as FARSITE and FlamMap require accurate spatially explicit estimation of canopy fuel complex characteristics. In the present study, we evaluated the potential use of very low-density airborne LiDAR (light detection and ranging) data (0.5 first returns m–2) – which is freely available for most of the Spanish territory – to estimate canopy fuel characteristics in Pinus radiata D. Don stands in north-western Spain. Regression analysis indicated strong relationships (R2=0.82–0.98) between LiDAR-derived metrics and field-based fuel estimates for stand height, canopy fuel load, and average and effective canopy base height Average and effective canopy bulk density (R2=0.59–0.70) were estimated indirectly from a set of previously modelled forest variables. The LiDAR-based models developed can be used to elaborate geo-referenced raster files to describe fuel characteristics. These files can be generated periodically, whenever new freely available airborne LiDAR data are released by the Spanish National Plan of Aerial Orthophotography, and can be used as inputs in fire behaviour simulation systems.


Sign in / Sign up

Export Citation Format

Share Document