Negative Trade-offs Between Community Forest Use and Hydrological Benefits in the Forested Catchments of Nepal's Mid-hills

Abstract

Widespread community forestry practices in Nepal's mid-hills catchments involve removal of forest products—including firewood, litter, fodder, and medicinal herbs—by the local communities. Uncertainty is growing about how sustainable the management of these catchments is and whether it can meet traditional needs and maintain ecosystem services, particularly water. As part of a broader study on the hydrological effects of community forestry practices, we measured selected soil properties, including saturated hydraulic conductivity (Ks), bulk density (BD,) and soil organic carbon (SOC) across 4 depths (0–10, 10–20, 20–50 and 50–100 cm) in 3 types of community forest sites—broadleaf, pine-dominated, and mixed—in the Roshi Khola catchment of Kavre district. The same measurements were made at a minimally disturbed religious forest site in the catchment that had higher Ksvalues than the mixed and broadleaf sites, signifying a lower degree of forest use-related disturbance. Likewise, SOC values for the religious forest were significantly higher (P < 0.05) and BD values significantly lower than the pine-dominated and mixed forest sites, particularly at shallower depths (0–50 cm). Importantly, comparison of the median Ksvalues (16–98 mm h–1) with rainfall intensities measured at the catchment showed the less intensively used pine-dominated site to be conducive to vertical percolation with possible greater contributions to subsurface storage even during high-intensity rainfall events. These results highlight the critical role of forest use practices in landscape hydrology and have implications for the management of the forested catchments in the broader Himalayan region, particularly in relation to the negative local perceptions of the role of pine plantations on declining water resources.

Keywords

• community forest use
• forested catchments
• saturated hydraulic conductivity
• water