Fuelwood characteristics and its relation with extractives and chemical properties of ten fast-growth species in Costa Rica

The aim of this study was to investigate the fuel characteristics (calorific value and fuel value index) of 10 fast-growing species in plantations in Costa Rica. The effect of the chemical properties, extractives and moisture content were evaluated. The results revealed that the gross calorific value varied from 16.5 to 20.6 MJ kg−1 for sapwood, and from 16.3 to 20.1 MJ kg−1 for heartwood. No consistency was observed with regard to which type of wood (sapwood or heartwood) had the highest gross calorific value. Large variations among the species were observed in the case of the fuel value index. For heartwood, the slope gradient of linear correlation was affected by lignin and extractives in sodium hydroxide and dichloromethane solution, whereas in the case of sapwood, only ashes content affected significantly to calorific value. For chemical parameters or the amount of extractives, carbon, nitrogen and lignin contents, ashes and extracts in dichloromethane influenced significantly the calorific value of heartwood. The calorific value in sapwood was affected by the amount of extractives in ethanol-toluene and the amount of ashes. Finally, the fuel value index was affected by the quantity of carbon, the extractives in sodium hydroxide and dichloromethane.