Natural Durability of Eucalyptus Clones against Termite Attack

Abstract

As essential components of the soil ecosystem, termites improve soil pH, organic carbon content, water content and soil porosity by cycling dead organics. However, termites also cause damage to food crops and trees. In Uganda, termites are major pests to Eucalypts including eucalyptus clones. This study assessed the natural durability of two Eucalyptus clones (GU 7 and GC 796) against termite attack. The specific objectives were to (i) identify the termite species that attack the wood from different parts of eucalyptus clones (ii) determine the weight loss of wood due to termite attack and (iii) determine the variation in termite resistance between the wood from the axial direction of the two clones. Two Eucalyptus clones GU 7 and GC 796 of four years old from Masaka district, central Uganda were cross cut into two proportions (at breast height and upper height). These were further plain sawn to samples of dimensions 20 x 20 x 20 mm size along the grain from the heartwood for the termite tests. Samples were taken to Olobai village, Kisoko County in Tororo district for field testing with termites. This area had been identified as a major site for termites in preliminary studies. The termite species that attacked the wood were identified and weight loss determined. The results showed that Macrotermes bellicosus and Pseudocanthotermes militaris attacked and damaged the wood. The mean weight loss was higher (26.8%) in GU 7 than in GC 796 (19%). Termite activity in Eucalyptus wood affected the axial position of the trees. The wood from the lower part of the trees in axial direction exhibited the most resistance to termites with 13