Effect of drying of different light hardwood tropical timber species on durability against Coptotermes curvignathus Holmgren under laboratory and field tests

Abstract

The effects of drying temperature and duration on the durability of Lagerstroemia sp. and Cinnamomum sp. against subterranean termites, Coptotermes curvignathus, were evaluated in no-choice and choice laboratory tests as well as in the aboveground test. Samples measuring 25 mm × 25 mm × 6 mm and 100 mm × 40 mm × 20 mm were dried in an oven at three different temperatures: 60°C, 80°C, and 100°C for two different time periods: 10 and 15 d. In comparison between the control sample and the treated sample, the control sample showed the highest MC, the lowest visual rating, the lowest termite mortality, and the highest weight loss. For the treated samples, the results show that the samples for both wood species have a low resistance limit to termites at low temperatures and a short-drying time. The weight loss is also high for samples with high MC. The mortality rate of termites was also high in samples dried at high temperatures over a long period of time compared with samples dried at low temperatures for a short period of time. The visual rating results also showed the same trend as the weight loss results. The results for these three categories are identical for the no-choice, choice, and aboveground tests. The analysis demonstrates that the high material resistance of tropical wood species is mostly dependent on the temperature and length of time spent in the kiln.