Modelling canopy fuel variables in Pinus pinaster Ait. and Pinus radiata D. Don stands in northwestern Spain
2013
Gómez-Vázquez, Ibán | Crecente-Campo, Felipe | Diéguez-Aranda, Ulises | Castedo Dorado, Fernando
CONTEXT : The fuel complex variables canopy bulk density and canopy base height are often used to determine crown fire initiation and spread. Direct measurement of these variables is impractical, and they must be estimated indirectly. AIMS : The objectives of the present study were to model the vertical profile of available crown fuel in maritime and radiata pine stands in NW Spain, using data from destructively sampled trees; to compare the values of the canopy fuel variables estimated by two different methods and to estimate these variables from common stand descriptors. METHODS : Systems of equations were fitted simultaneously to address the inherent correlations between available crown fuel components and between the canopy fuel variables. Heteroscedasticity and autocorrelation were also taken into account in the fitting process, where necessary. RESULTS : The values of the canopy fuel variables varied greatly depending on the estimation method used. Models for predicting the variables at stand level explained a high percentage of the observed variability. Crowning is more likely in maritime pine than in radiata pine stands. CONCLUSIONS : Although the approach used in this study provides a realistic depiction of the vertical distribution of crown fuel, it departs from the requirements of Van Wagner’s model. The method used to estimate canopy fuel variables affects fire modelling results and thus the design of fuel treatment projects.
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