Comparative vegetation analysis under multipurpose plantations

A study was conducted in and around Chandigarh, India to analyse the vegeta tion under the monoculture plantations of exotic (Eucalyptus tereticornis, E. citriodora, Populus deltoides and Leucaena leucocephala) and indigenous (Albizia lebbeck, Dalbergia sissoo and Acacia nilotica) tree species. Exoti c plantations were observed to harbour less number of plant types compared to indigenous ones. In addition, but their density and biomass were also dr astically reduced. Likewise, the indices of diversity, evenness and richnes s were also comparatively less under exotic plantations indicating the homo geneity and thus instability of the vegetation under them. Further, the soi l collected beneath these exotic plantations was found to be rich in phytot oxic allelochemicals as indicated by their bioefficacy against Phaseolus au reus - a test plant.