DefinePK

Abstract

ABSTRACT Regular burning, canopy removal and clearance of ground cover on the slopes have led to colonization by the bladey grass Imperata cylindrica (L.) P. Beauve. a pan-tropical weed. Plots with and without the presence Imperata were sampled over six sites along a single watershed. The number and biomass of Chir pine (Pinus roxburghii Sargent) seedlings of all ages were found to be markedly less in plots where Imperata ground cover exceeds 75%. Over the range of sites, however, other factors of the pine's regenerative ecology appear to dwarf this effect and analysis of variance showed the difference to be non-significant. Mycorrhixal growth intensity on the seedling roots was also assessed at different depths in the soil in each sample plot and an attempt was made to correlate this with soil phenol concentration. Results were inconclusive and lend no support to the hypothesis positing allelopathic suppression of mycorrhiza by phenols secreted by Imperata. No recommendations for management are made, as the problem of Imperata colonization does not appear pressing, relative both to the wider problem of forest clearance in the area, and to the cost of any possible solution.