Production of wood biomass by high density Acacia nilotica plantation in semi-arid region of central India

Acacia nilotica (Babool) is one of the most common and important tree species found in dry areas of the Indian sub-continent and Africa. It is one of the most prominent tree species for agro-forestry systems in the dry land areas of India. A total of 75 trees (30 trees each at age of 4.5 and 5.5 years and 15 trees at 6.5 years) were harvested. Out of six non-linear functions fitted, parabolic models viz., W_b = -1.931 + 0.816 D + 0.164 D² (R²=0.899), Wt = -0.519 -0.065 D + 0.557 D² (R²=0.929) were found best in case of branch wood (W_b) and total wood biomass (W_t) whereas, Chapman-Richard model, W_s = 109.474 (1 – e^{−0.09 D}) ^2.685 (R²=0.935) was found best in case of stem wood biomass (W_s). These models were validated and compared on the basis of mean bias, mean absolute error and Root mean square error (RMSE). Prediction errors of only 0.897, 0.706 and 0.742 kg in branch wood, stem wood and total wood biomass, respectively was found. Total wood biomass production varied from 12.13 t ha⁻¹ at 4 years age to 35.64 t ha⁻¹ at 7 years age. Total wood volume was estimated to be 0.011 m³/tree at the age of 4 years, which increased upto 0.033 m³/tree at the age of 7 years.