FUNGAL SUCCESSION AND MICROBES ON LEAF LITTERS IN 2 DEGRADED TROPICALFORESTS OF NORTHEAST INDIA

The effect of forest degradation on the population of fungi and bacter ia was studied on leaf litter in two forest stands developing on young and old jhum fallows (5 years and 15 years respectively), showing dif ferent stages of regeneration. The fungal and bacterial counts were hi gh on decomposing leaf litters in the young forest stand compared to t he old forest stand. They exhibited a marked seasonal variation in bot h the forest stands. In the young stand the highest bacterial count wa s recorded in May and June for Ageratum conizoides and Mallotus philip pinensis litters respectively. In the old stand two bacterial peaks, o ne in June and another in August, were observed for Holarrhena antidys enterica and Vitex glabrata leaf litters. The highest fungal counts, h owever, were observed in May in all leaf litters. The diversity index of fungal species was higher in the old forest stand than in the young er one and was highest in woody leaf litters compared to herbaceous li tter. A marked variation in the distribution of different fungal group s was recorded. Initially the herbaceous litter harboured more phycomy cetes, while deuteromycetes initially dominated the leaf litter of woo dy plants.