Growth and pulpwood traits of Leucaena leucocephala and Eucalyptus camaldulensis at rainfed and irrigated sites in southern India

Abstract

Growth and wood traits of Leucaena leucocephala subsp. glabrata were compared with India's most widely grown pulpwood, Eucalyptus. Three Leucaena seedlots and sixty-four Leucaena clones selected in plantations established from two Indian land races and a Hawaiian seed source were tested together with five commercial E. camaldulensis clones at two contrasting sites in southern India. At the wetter, irrigated site, the three sources of Leucaena clones had significantly greater 4-year height and similar mean stem diameter to the Eucalyptus clones, while the Leucaena seedlots were slower-growing. At the semi-arid, rainfed site, Eucalyptus grew faster and had better survival than the three sources of Leucaena clones, which again were similar in their performance and superior to the Leucaena seedlots. Basic densities, determined from breast-height wood cores, of 4-year-old Leucaena and Eucalyptus were quite similar (568 and 534 kg m-3 respectively) at the irrigated site, but at the rainfed site Eucalyptus wood density was higher (590 kg m-3), while that of Leucaena was lower (508 kg m-3). The kraft pulp yield (KPY) of Leucaena clones was about 1.5 % higher than Eucalyptus at both sites; KPYs of both species were 1.8 % lower at the rainfed than the irrigated site. Leucaena fibres were 31 % and 39 % longer and 65 % and 58 % wider than Eucalyptus, at the irrigated and rainfed sites respectively, and had lower cell wall proportions. Differences among Leucaena clones were significant for growth traits and for most wood and fibre traits, indicating the potential for selecting fast-growing Leucaena clones with improved wood properties. Clonal Leucaena plantations can serve as a productive and complementary pulpwood crop to Eucalyptus in southern India, increasing the yield and strength of blended pulps.