EFFECT OF EXTRACTIVES ON HEATING VALUE OF GMELINA ARBOREA

Abstract

The difference in heating value of extractive-free wood and unextracted wood was used in determining the influence of extractives on the heating value of Gmelina arborea. Heartwood, sapwood, bark, terminal branches and leaves were extracted with benzene/ ethanol solution, absolute ethanol and water. The heating values of extractivefree samples and the unextracted control were measured. The mean percentage contribution of extractives to heating values was 23.2, 20.1, 31.5, 17.0 and 22.1% for heatwood, sapwood, bark, terminal branch and leaves, respectively. Correlation matrix suggested that other chemical components of wood also influenced the variation in heating value.