Tree canopy development in young plantations raised on coalmine spoil affects the growth of herbaceous vegetation

Abstract

The grasses Pennisetum pedicellatum and Heteropogon contortus were sown in plantation plots of 11 multipurpose trees species on coal mine spoils, as part of the Jayant Project of Northern Coalfields Limited at Singrauli in Madhya Pradesh (India). The plantations were established in July 1993, and the grasses sown at the same time and again 1 yr later. After 3 yr of growth (in 1996) the plantation canopies affected the growth of the grasses, with the dense canopies of Dendrocalamus strictus, Pongamia pinnata and Leucaena leucocephala completely eliminating the sown grasses. Under the dense canopy of Gmelina arborea only H. contortus grew and P. pedicellatum was eliminated. If the grasses are to be retained for the sake of biodiversity and stabilization of the community it is recommended that the plantation plots be thinned after 3-4 yr, and that only H. contortus be sown.