Department of Forestry and Environmental Science
UNIVERSITY OF SRI JAYEWARDENPURA, SRI LANKA ../
FORESTRY AND ENVIRONMENT SYMPOSIUM
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|FORESTRY SYMPOSIUM 1996|
D G Dantha Darshani and Hiran S Amarasekara
University of Sri Jayewardenepura
This study examined the possible causes of splitting in Eucalyptus and how it can be reduced. The samples of Eucalyptus logs were obtained from even-age (35 year) plantation at Kandapola in the Nuwara Eliya District. The species selected were Eucalyptus microcorys and Eucalyptus grandis.
The pattern of splitting and splitting intensity were measured daily. It was observed that the Eucalyptus grandis was subjected to more severe splitting than Eucalyptus microcorys. The amount of splitting varied according to the species, bole height in the tree and the diameter of the bole. Larger diameter logs showed more splitting than smaller diameter logs. Higher splitting intensity was recorded in the top height of Eucalyptus grandis tree.
Eucalyptus microcorys showed higher density than Eucalyptus grandis and both species showed an increasing density from pith outward. Two stages of splitting were observed: at the first stage splitting started from the pith and extended towards the bark, there minor splits started from bark and extended towards the pith during the second stage. The time taken to complete splitting was increased with increasing Equilibrium Moisture Content (EMC). No relationship was observed between heartwood percentage and splitting.
It was found that the splitting can be reduced by fixing gangnails at the cut surface of Eucalyptus grandis logs, which results in reducing the stress from pith outward. Applying vaseline on the cut surfaces of the logs also reduced the incidence of splits. Although these treatments reduce splitting, it was difficult to stop it completely using these treatments. All treated logs ( both fixing gangnails and applying Vaseline ) showed lowest splitting.
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