Variation of sapwood and heartwood content in half-sib progenies of Eucalyptus tereticornis Sm.

Abstract

Thirty six progenies of Eucalyptus tereticornis Sm. from seven geographical locations were evaluated for sapwood and heartwood content variation at Punjab Agricultural University, Ludhiana. The maximum wood and heartwood diameter were recorded in genotype 142, whereas, maximum heartwood content was in genotype 4. The heartwood stopped within the tree at 55 to 65 % of total height. Heartwood was present in all trees attaining the 12 m height but at the 14 m height, only seven trees showed heartwood. Sapwood radial growth was lowest at the base and showed maximum variability between trees from 4.29 to 8.61 cm of the pooled mean of sapwood at different height levels. Heartwood taper was higher than tree taper in the lower part of the stem but slightly lower than the upper part of the stem. The mean heartwood content was 53.3 % of the total tree volume at breast height. Heartwood dimensions from wood diameters were estimated by using a linear model. The heartwood diameter was positively correlated with radial tree growth and showed a good linear regression with a high coefficient of determination (R² = 0.80) to the wood diameter, whereas, sapwood width was independent on the diameter.