Evaluation of kraft pulp, fibre and paper traits of interspecific hybrid Corymbia clones at four years

Abstract

Two interspecific Corymbia hybrid clones, ITC 2081 & CH440 (Corymbia torelliana × C. citriodora subsp. variegata), were evaluated for growth, pulp, fibre and paper properties at four years in comparison to an E. camaldulensis (Ec) clone. Wood basic density and fibre traits were estimated from increment core samples and logs were chipped for evaluating pulp and paper traits. The Corymbia clones had comparable growth, but wood basic density was 12% higher than the Ec clone. The fibre traits were superior, with 24% larger fibre in the Corymbia hybrid clones, and 2% higher pulp yield (Kappa number 17) than the Ec clone. The Corymbia hybrid clones had comparable unbleached hand sheet brightness of the Ec clone but were superior in parameters like sheet stiffness, thickness, burst and tear factor. While Ec clones have attained the threshold of pulp wood traits improvement, the new Corymbia hybrids have demonstrated potential for improving the profitability of pulp industries in India.