Optimum stand density of Leucaena leucocephala for wood production in Andhra Pradesh, Southern India

Leucaena leucocephala is widely used as raw material for the manufacture of paper and packaging material and in biomass based power plants in the state of Andhra Pradesh, Southern India. Experiments were conducted to study the affect of tree density on the growth, biomass partitioning and wood productivity. Six treatments 1 × 1 m, 1.3 × 1.3 m, 3 × 0.75 m, 3 × 1 m, 5 × 0.8 m and 3 × 2 m corresponding to a tree density of 10,000, 6666, 4444, 3333, 2500 and 1666 were evaluated with leucaena variety K636. At 51 months after planting, spacings significantly influenced tree height, diameter at breast height (DBH), number of branches and biomass partitioning. Wider tree rows resulted in greater tree height and diameter growth resulting in higher per plant productivity. At harvest, 70% of trees in 3 × 2 m attained a diameter of more than 7.5 cm, while 35% of the trees attained the same DBH in 1 × 1 m spacing. Increased spacing levels decreased the relative amount of growth allocated to the bole of the tree. Marketable biomass yield was highest with 1 × 1 m spacing. Spacing of 3 × 0.75 m produced marketable biomass comparable to that of 1 × 1 m and greater proportion of stems with more than 5 cm diameter. Leucaena can be grown at 3 × 0.75 m spacing either for pulpwood or fuelwood depending on the prevailing market prices and demand.