Deriving forest canopy fuel parameters for loblolly pine forests in eastern Texas Muge Agca, Sorin C. Popescu, and Clinton W. Harper Abstract: Crown fires, the fastest spreading of all forest fires, can occur in any forest type throughout the world. The overall aim of this study was to estimate forest canopy fuel parameters including canopy bulk density and canopy base height for loblolly pines (Pinus taeda L.) at the plot level using both allometric equations and CrownMass/FMAPlus software. Allo- metric equation results were compared with the CrownMass outputs for validation. According to our results, the calculated average canopy bulk density values, across all 50 plots, were 0.18 and 0.07 kg/m 3 for the allometric equation and the CrownMass program, respectively. Lorey’ s mean height approach was used in this study to calculate canopy base height at the plot level. The average height values of canopy base height obtained from the Lorey height approach was 10.6 m and from the CrownMass program was 9.1 m. The results obtained for the two methods are relatively close to each other, with the estimate of canopy base height being 1.16 times larger than the CrownMass value. This study provides a practical method for quantifying these parameters and making them directly available to fire managers. The accuracy of these parame- ters is very important for realistic predictions of wildfire initiation and growth. Résumé : Les feux de cimes, les feux de forêt qui se propagent le plus rapidement, peuvent survenir dans n’importe quel type de forêt partout dans le monde. L’ objectif global de cette étude consistait à estimer les paramètres des combustibles dans le couvert forestier, incluant la densité apparente du couvert et la hauteur de la base du couvert pour les pins à encens (Pinus taeda L.) à l’échelle de la placette, à l’aide des équations allométriques et du module CrownMass du logiciel FMA- Plus. Les résultats de l’équation allométrique ont été comparés à ceux du module CrownMass à des fins de validation. Selon nos résultats, les valeurs moyennes calculées de la densité apparente du couvert pour l’ensemble des 50 placettes étaient res- pectivement de 0,18 et 0,07 kg/m 3 pour l’équation allométrique et le module CrownMass. L’approche de Lorey pour la hau- teur moyenne a été utilisée dans cette étude pour calculer la hauteur de la base du couvert à l’échelle de la placette. Les valeurs de hauteur moyenne de la hauteur de la base du couvert étaient de 10,6 m selon l’approche de Lorey et de 9,1 m se- lon le module CrownMass. Les résultats obtenus avec les deux méthodes sont relativement proches l’un de l’autre; la valeur de la hauteur de la base du couvert estimée par l’approche de Lorey est 1,16 fois plus grande que celle obtenue avec le mo- dule CrownMass. Cette étude fournit une méthode pratique pour quantifier ces paramètres et les rendre directement disponi- bles pour les gestionnaires du feu. La fiabilité de ces paramètres est très importante pour prédire de façon réaliste l’initiation et le développement des feux de forêt. [Traduit par la Rédaction] Introduction Wildland crown fires are one of the most important and prevalent types of disasters because of their potential envi- ronmental impacts (Pyne et al. 1996). In recent years, the number of crown fires has significantly increased, threatening life, property, and natural resources in the world (Falkowski et al. 2005). Fire managers and foresters use the term “crown” to refer to the branches and foliage of individual trees and the term “canopy” refers to the aggregation of crowns at the stand level (Scott and Reinhardt 2001). Canopy fuels are defined as all burnable materials, which include live and dead foliage, lichen, and redundant stem and branchwood located in the upper forest canopy (Chu- vieco and Congalton 1989). Canopy fuels are important in- puts for fire behavior models that predict crown fire behavior and spread (Scott and Reinhardt 2001). Therefore, fire managers need more precise spatially explicit information about the fuels they manage. Canopy bulk density (CBD) and canopy base height (CBH) are the two main canopy fuel parameters (illustrated in Fig. 1) needed to predict crown fire spread (Van Wagner 1977, 1993; Finney 1998). CBD is de- fined as the density of available canopy fuels, i.e., a measure of the amount of fuel contained per unit of canopy volume (Scott and Reinhardt 2001; Hall and Burke 2006). The CBD is a bulk density of the whole stand, not a bulk density of an individual tree. CBH is defined as the vertical distance be- Received 8 November 2010. Accepted 6 June 2011. Published at www.nrcresearchpress.com/cjfr on 28 July 2011. M. Agca and S.C. Popescu. Spatial Science Laboratory, Department of Ecosystem Science and Management, Texas A&M University, 1500 Research Parkway, Suite B221, College Station, TX 77843, USA. C.W. Harper. Texas Commission on Environmental Quality, Air Quality Division, P.O. Box 13087/MC-164, Austin, TX 78711-3087, USA. Corresponding author: Muge Agca (e-mail: mugemutlu@tamu.edu). 1618 Can. J. For. Res. 41: 1618–1625 (2011) doi:10.1139/X11-082 Published by NRC Research Press Can. J. For. Res. 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