Litter Fall, Litter Decomposition and Soilconditions of shivapuri National Park, Kathmandu

Abstract

I conducted my research during January 2005–December 2005 in Shivapuri National Park and as a quick reference in Coronation Garden of Tribhuvan University, Katmandu to explore litter fall, litter decomposition and soil conditions of the forest ecosystems.The site was divided into three stations which were again divided into three sampling plots of50 meter squares. I identified tress and measured for DBH and collected nine samples oflitterfall and soil each during autumn, winter, spring, and summer.The litter collections were separated into leaf litter and twigs,were oven dried for 24 hours and weighed in the Central Department of Zoology laboratory in every three months. Rate of litter decomposition was investigated by field experiments. Sixnyl on mesh bags with equalamount of fresh litter (100gm) from respective stations were buried in each forest and weight loss was noted by weighing after three months.The soil samples were analyzed fordifferent parameters in the laboratory of Department of Agriculture, Harihar Bhawan.Field surveyshowed that there werea total number of 160 trees of11species belonging to6 families in the natural forest and in the man-made forest there were 92 trees belongingto14species and 12 families. In the natural forest,Fagaceae family was more common,Quercusglaucashowed the highest density (555.6trees/ha), the most frequent species wasCastanopsis indica,Rhododendron arboreum was with the highest basal area (0.037 m )and the highest Importance value (IV) (49.9%). In the man-made forest,FagaceaeandSalicaceae families were more common, Salix babylonicashowed the highest density,Lagerstroemia indicawas the most frequent andPopulus euro-americanashowed thehighest basal areawith the highest IV(50.0%).The total annual litter fall recorded were5037.50kg/ha(79.8% leaf fall)in the natural forest and 4251.90kg/ha(82.0% leaf fall)inthe man-made forest. Thelitter fall was highest in autumn, 1632.6 kg/haand 1362.7kg/hain the natural forest andin the man-made forestrespectively.The litter decomposition ratewas the highest in thesummer season in which theweight loss was38.0 ±1.7gm in thenatural forest and32.5 ± 1.61gm in the man-made forest. The mean weight loss rate wasfound slightly higher in the natural forest (0.3225 g/day) than in the man-made forest(0.2725 g/day).The organic matter, total nitrogen and Phwere the highest in thewinterseason whereas available potassium and phosphorus were the highest in the summerseason in both the forest types. The man-made forest (Ph-5.6) wasmore acidic than thenatural forest. The organic matter and total nitrogen were higher in thenatural forest thanthe man-made forest whereas available phosphorus and potassium were higher in the man-made forest than in the natural forest. The major group of organisms contributing todecomposition process was oligochaeta, rootlets, fungi, isopods, araneae, coleopteran,wild boar, porcupine, monkey, deer, beer and jackal.