Effect of thermal modification on colorimetric, chemical characteristics, and termite resistance of short-rotation African mahogany ( Khaya ivorensis ) wood

Thermal modification is an alternative to enhance the aesthetic and technological attributes of wood. African mahogany (Khaya ivorensis A. Chev.) wood has high commercial value and is gaining increasing presence in the Brazilian market; however, there are still gaps regarding the effects of thermal modification on the quality of wood from young trees. Thus, this study aimed to evaluate the effects of heat treatment on the colorimetric and chemical characteristics, as well as the termite resistance, of short-rotation (19-25-year-old) African mahogany wood. Samples derived from sapwood/heartwood and heartwood were subjected to thermal modification (180 °C and 200 °C) and compared to the control (25–30 °C). Color, chemical composition (total extractives, lignin, holocellulose, and ash), and resistance to dry-wood termites (Cryptotermes brevis) and arboreal/soil termites (Nasutitermes corniger) were evaluated. Thermal modification intensified the darkening and color uniformity of the wood, resulting in a relative increase in lignin, extractives, and ash content, and a corresponding reduction in holocellulose. The temperature of 180 °C resulted in better performance against dry-wood termites, but without a pronounced effect against soil termites. Thus, thermal modification is an alternative to increase the aesthetic value and improve the termite resistance of the wood.