Preliminary results of investigations into the air-drying of debarked logs of four eucalyptus species in the natal Midlands

Abstract

The results are described of preliminary investigations made during 1976–77 into the air-drying rate of debarked logs of E. elata, E. fastigata, E. macarthurii and . nitens grown in the Natal Midlands. It was found that for practical purposes the drying rates for these species are the same, that the greatest changes in drying rate occur as a result of the weather, and that smaller logs dry faster than bigger logs, the differences being proportional to tip diameter. Under average conditions the moisture content of logs is dependent mainly upon initial moisture content immediately after felling. If the initial moisture content is high, 8 weeks air-drying will not reduce this to an acceptable level for the timber trade. The average density for these species appears to be lower in the Natal Midlands than in the southeastern Transvaal. There might be a relationship between density and initial moisture content immediately after felling. The volume shrinkage of roundwood of these species is high and amounts on average to more than 5 per cent.