fire ecology of ground vegetation in pinus roxburghii sargent plantations in north-west himalaya - floristic composition and species diversity

effect of fire on phyto-sociology of understorey vegetation in chir pine forests of three different silvological characteristics was compared with pure grassland. 15 grasses, 1 sedge, 5 legumes and 21 non-legumes were recorded in the four study sites. floristic composition gradually increased from june to august and then declined slowly by october in all the plots. maximum number of species was in twice-burnt plots followed by once burnt and unburnt plots. least similarity index was recorded for twice burnt plots and unburnt plots. density of vegetation increased from june to mid-rainy season and thereafter decreased till october. density of vegetation in four sites decreased in order: open grassland > sapling chir pine stand > pole stage chir pine stand > mature trees chir pine stand. density of vegetation increased when fire was imposed in plots. it decreased in the order: twice burnt plots > once burnt plots > unburnt plots. it was recorded that fire in chir pine forests are good for herbage growth and development.