Influence of planting density on growth and biomass productivity of Terminalia arjuna under sodic soil sites

The producitity of Terminalia arjuna was investigated under varied plant spacing (10-, 20-, 30-, 40- and 50,000 trees ha−1) on a highly alkaline soil site (pH 8.6 to 10.5) in order to maximise biomass production and to assess optimum stocking density. The species showed a very high survival percentage even when planted in high densities. Closely spaced plants were significantly taller than the more widely spaced plants of the same age. Mean stand basal area and volume increased with increase in planting density in the initial years but differences in basal area among 30- to 50,000 trees ha−1 treatments were not significant at the age of three years. The trees at wider spacing had higher individual biomass than those at closer spacing. The study showed that after 4 years an optimum biomass of 22.7 t ha−1 was produced in the 30,000 trees ha−1 treatment. Densities higher than 30,000 trees ha−1 were found to be supra-optimal and resulted in over-crowding. The biomass produced in high density plantation of T. arjuna was found suitable for use in gasifiers.