| This study examines associations between human-induced disturbance to forests, in the form of forest biomass harvesting, and the structure, composition, and productivity potential of Schima-Castanopsis dominated forests in Nepal's central middle hills. The study objectives are to: (1) document the ecology of the forests and establish baseline data, (2) increase our understanding of relationships between disturbance and properties of impacted ecosystems, and (3) identify promising ecological variables for use as indicators of forest disturbance and degradation. A long-term goal of this study is to use such variables to develop a protocol for objectively classifying forests into degradation levels.; Five forest stands representing relatively undisturbed to severely disturbed conditions were sampled. Data represent measures of human-induced disturbance, stand and forest floor characteristics, soil properties, richness and abundance of vascular plant species, and major topographic covariates. A Subsistence Anthropic Disturbance-Index (SAD-Index) was developed to quantify forest disturbance. Five variables representing measures of forest biomass harvesting intensity were selected to develop the SAD-Index: (1) estimated cut proportion of overstory basal area, (2) cut proportion of overstory trees, (3) cut proportion of saplings, (4) lopped proportion of overstory trees, and (5) lopped proportion of saplings.; Two major relationships between disturbance intensity and ecological attributes are observed: (1) unimodal (hump-shaped) and (2) monotonic. Among woody plants, the largest differences are observed for overstory variables and the smallest for ground-vegetation variables. Among site productivity variables, monotonic relationships with disturbance intensity are observed for relative herbaceous plant cover, index tree height, mean height asymptote of all Schima-Castanopsis trees, and mean height asymptote of dominant and co-dominant Schima-Castanopsis trees. Unimodal relationships with disturbance intensity are observed for most soil variables and for mean aboveground biomass and dbh of index tree. Species richness of shrubs/woody vines and herbs appears to be strongly related to disturbance. Osbeckia stellata, Phyllanthus parvifolius, Lantana camara, Inula cappa, Crotalaria cystoides, and Hypericum uralum appear to be good indicators of disturbed forest conditions. Ardisia macrocarpa and Sarcococca coriacea appear to be good indicators of relatively undisturbed forest conditions. Major study findings and their implications for future research and forest management in the region are discussed.* ftn*Originally published in DAI Vol. 58, No. 2. Reprinted here with corrected title. |
