Intra clonal variations of specific gravity and selected mechanical properties of Eucalyptus tereticornis Sm.

Abstract

Intra clonal variation of specific gravity (sp. gr.) and selected mechanical properties in 4–5 years old trees of five clones of Eucalyptus tereticornis Sm. developed by ITC Bhadrachalam (clone 3, 4, 6, 7 and 10) is reported. Four trees of each clone were studied from Sarapakka, Andhra Pradesh (India). There is a significant difference within the clone in the sp. gr. for all the clones except for clone 10. Differences in within clone bending properties (MOE, MOR and FS at LP) in green and air-dry condition on the contrary are non-significant in all the clones. Very similar trend is observed for CS at LP (except for clone 7) and hardness (except for end hardness in clone 4 for dry condition and clone 7 for side hardness in green condition). Maximum crushing strength (MCS), however, showed significant difference in all the clones except for clone 7. In general, it can be concluded that difference in strength properties is non-significant and do not follow the trend of specific gravity. Trees of clone 4 have highest values for all the properties tested among the five clones. Trees of clones 3 and 10 have identical sp. gr. and are lowest among all the clones. MCS and CS at LP is lowest in trees of clone 10 closely followed by clone 3. Trees of clone 3 have lowest bending properties and hardness properties closely followed by clone 10. On an average clone 10 reports the highest girth for all the trees followed by clone 6. Clone 4 reports the lowest girth for the trees. No specific trend was observed between sp. gr. verses strength properties and girth of the trees versus sp. gr. and strength properties although there seems to be general reduction in strength and sp. gr. with increase in girth.