Abstract
The variation in root biomass and extent of expansion in Eucalyptus camaldulensis, Bombax ceiba and Populus deltoides on planting along north-south direction were studied at Punjab Forestry Research Institute, Faisalabad, Pakistan The Trees were growing in lines adjacent to agricultural field along north-south direction with trenches along eastern and western direction Each type of tree was replicated thrice and they were eight year old Soil samples were collected up to a depth of 50 em along northern and southern aspect at 1, 2, 3 and 4 metres. Roots were separated from the soil and weighed to measure biomass. P. deltoides had higher root biomass than E camaldulensis and B ceibe. Root biomass was high on the northern aspect of E camaldulensis and B ceiba as compared to southern aspect and it decreased with increase in distance from the base of the tree. There was no difference in root biomass of P deltoides between northern and southern aspects. Key words: Root biomass, toot expansion
