Variation in Wood Properties of Eucalyptus Hybrid Clones and Local Landraces Grown in Kenya

Abstract

The wood properties of 5 to 6 years old Eucalyptus grandis X E. camaldulensis hybrid clones (GC) and local landraces of E. grandis. E. tereticornis, E. camaldulensis and E. saligna were studied at 4 sites in Kenya. Physical properties were determined using samples obtained at various heights, namely mechanical properties on butt logs and calorific values at tree DBH (diameter at breast height). Standard procedures of determination of wood properties were used. Results showed that site had significant effect (P<0.001) on basic density except in GC 15. The calorific values ranged from 4.9 to 5.1 for GCs and 4.9 to 5.0 for landraces. The mean Modulus of Elasticity (MOE) ranged from 7866 to 15080 MPa for GCs and 8335 to 11892 MPa for landraces. The mean Modulus of Rupture (MOR) ranged from 87.9 to 129.4 MPa for GCs and 67.9 to 106.7 MPa for landraces. The mean compression strength, shear strength and surface hardness varied significantly (P<0.05) with sites and tree type. It was concluded that at age 5 to 6years, wood from the GCs had the same or higher density, MOE, MOR, surface hardness, shear and compression strength, but the same or lower moisture content and volumetric shrinkage, compared to the landraces grown under similar conditions. However, the clones and landraces were similar in calorific values.