FAST ESTIMATION OF THE CALORIFIC VALUES OF FOREST FUELS BY NEAR-INFRARED REFLECTANCE SPECTROSCOPY

Fuel calorific value is an important parameter in fire behaviour. The objective of this study is to evaluate the potential of using near-inf rared reflectance spectroscopy (NIRS) for determining the calorific va lue of fuel. Fifty samples of various fuel components from the Mediter ranean forest (17.1-24.6 MJ.kg(-1)) were used to establish a calibrati on equation between NIR spectra (1100-2500 nm) and calorific value. Th e coefficient of determination (r(2)) of the regression between predic ted and measured values was 0.92 and the standard error of cross valid ation was 0.50 MJ.kg(-1), i.e., twice the standard error of the measur ement by the conventional method in a bomb calorimeter (0.23 MJ.kg(-1) ). Using this calibration equation, the calorific values of two sets o f 15 samples collected weekly during the fire season from two shrub sp ecies, Arbutus umedo L. and Erica arborea L., were predicted. The r(2) between NIRS-predicted and measured values were 0.79 and 0.76, respec tively, and the standard errors of prediction were 0.36 and 0.21 MJ.kg (-1). These results show that NIRS is less accurate than the standard method but it can be used to quickly determine the calorific value of fuels when a large number of measurements are required.