Effectiveness of selected preservatives in protecting ugandan grown eucalyptus grandis wood against termite attack

Abstract

Termites are one of the major wood destroying agents in the tropics and with the increasing rate of deforestation, there is a need to protect wood from biodegradation in order to extend its service life. In this study the incidence and severity of termite attack on Eucalyptus grandis sapwood treated with CCA, used engine oil and neem extract were investigated. Sixty samples (20 × 20 × 300mm) were prepared from the sapwood at mid-height of the tree of E. grandis and air seasoned for two weeks then treated with the preservatives. An area of 20m by 20m in a pine plantation and 15 plots of 1m by 1m were selected at random. Four samples, one from each treatment, were placed at the corners of the selected plots.

Inspection and evaluation of stakes was made by visual assessments after every 30 days for any sign of termite attack for a period of 8 months. The specimens were removed from the ground, damage assessed and returned to the ground. After 4 weeks all the untreated wood samples had been attacked, neem extract treated wood samples were attacked after 17 weeks and used engine oil treated samples after 30 weeks. None of the CCA treated wood samples were attacked by the end of study period. Chi square analysis showed a high association between treatment and incidence as well as between treatment and severity. It was recommended that further research be carried out on neem extract using different concentrations.