Restoration of opencast coal mine spoil by planting exotic tree species: a case study in dry tropical region

Abstract

Growth performance, biomass accumulation, and net primary productivity (NPP) of five exotic plant species planted to stabilize and improve the coal mine spoils in India were assessed. The selected exotic species were very successful under afforestation programs on wastelands. Plant species showed a considerable variations in growth characteristics with response to their ages on coal mine spoils. The shoot height was found to be maximum in Eucalyptus hybrid and minimum for Cassia siamea during whole course of study. The circumference of plants varied significantly due to plant species as well as age. Shoot biomass increased by 2.5–3 times in 7 years old plantations of different plant species as compared to those of 4 years. Marked increments were also observed in the major root and fine root biomass with increasing age of plantations. Total biomass accumulation was recorded maximum in E. hybrid and minimum in C. siamea. The NPP also followed a similar trend as total biomass. The maximum contribution was made by stem with branch in comparison to other components in NPP among different plant species. Shoot production including branches was found to be maximum in E. hybrid and minimum in C. siamea, whereas the NPP of major roots did not show a similar trend as that of shoot. On the basis of biomass and primary productivity, E. hybrid and Acacia auriculiformis were found suitable for plantation on coal mine spoil land.