Role of acacia plantations on regeneration of native tree species in the Upper Palni hills, Tamil Nadu, India
Student name: Mr Thanggoumang Hangsing
Guide: Dr Joachim Schmerbeck
Year of completion: 2012
Host Organisation: TERI University, New Delhi and University of Freiburg, Germany
Supervisor (Host Organisation): Dr Stefanie Gartner
Abstract: The study aims to understand the status of native tree regeneration under Acacia plantations of the Palni Hills. A
total of 12 stands with dominant canopy composition of Acacia species were selected on the basis of exposition and
density. 5 plots were placed in each stand randomly in a systematic grid. The native tree regeneration was assessed
in a 5X5m plot nested inside a 7X7m plot. All native tree regeneration below 7cm diameter at breast height was
measured at breast height and root collar. Height and damages of each tree was also assessed. Tree regeneration
was classified according to pre-defined strata as low (<150cm), middle (150-300cm) and upper (above 300). The
dominant plant species community growing under Acacia plantations in the Palni Hills are early successional
species. 19 tree species were found under the Acacia plantations belonging primarily to the Lauraceae family. Most
of the species are dispersed by birds. There was significant difference (p<0.05) of native tree regeneration with
different densities of main stand stem density. The major portion of regeneration belongs to the regeneration of less
than 150cm. Overall, there seems to be suppression of regeneration in larger growth stages. There was a significant
positive correlation of tree species richness (rs =0.358, p<0.01) and density (rs =0.224, p<0.05) with altitude. The
native tree regeneration richness (rs = - 0.358, p<0.01) and density (rs = -.309, p<0.01) also decreased with
increasing distance from the native forest. Of all the life forms, grass cover is significantly negatively correlated
(rs= - 0.261; p<0.05) with native tree regeneration density. Acacia plantations do play a pivotal role in bringing
about germination of seeds, however, there must be management intervention which will enable native tree
regeneration to attain larger growth stages through protection against browsing which may be a significant
detriment for regeneration.
Keywords : Exotic, plantations, regeneration, shola, succession, dispersal, browsing
