Treatment of Selected Lesser Used Timber Species against Subterranean Termites using Heartwood Extracts from Teak (Tectona grandis) and Dahoma (Piptadeniastrum africanum)
A Asamoah, C Antwi-Boasiako
Lesser used timber species represent a valuable material for all-purpose uses but the problem is that most of them are not durable. They have, for this reason, been treated with all manner of chemicals to enhance their natural durability, especially in the tropics. Often, most of these chemicals pose a threat to the environment. Currently, one probable measure of avoiding such a threat to the environment and organisms is to treat non-durable timbers with extracts from other durable species.
Some Ghanaian lesser used timber species were impregnated with heartwood extracts of Teak (Tectona grandis) and Dahoma (Piptadeniastrum africanum) and exposed in the field to subterranean termites for 4 months. The effect of these extracts in enhancing the durability of these timbers was studied in accordance with EN 252. Some of the parameters considered were visual characteristics, hardness and weight loss after exposure.
The results showed some species to be significantly different in durability between control samples and their treated counterparts (after 4 months) and not in others (after 4 months). Moreover, among the species, durability was high in Pertersianthus macrocarpus while the others followed in the following order: Albizia ferruginea = Blighia sapida = Sterculia rhinopetala > Amphimas pterocarpoides > Sterculia oblonga = Cola gigantean = Antiaris Toxicaria > Canarium schweinfurthii.