PENGARUH PEMBANGUNAN HUTAN TANAMAN TERHADAP TATA AIR (STUDI SIMULASI DI DAS CITANDUY HULU) (Effect of Plantation Forest Development on Water System, A Simulation study in Upper Citanduy Watershed)

Plantation forest development was dominated by commercial timber-producing of tree species, coniferous and deciduous. Plantation forest development affects water yield in an area. Research on the effect of plantation forest development on water yield at the watershed scale has not been widely carried out. This study aimed to predict the environmental effect of plantation forests development three groups of commercial timber-producing groups, namely needle-leaf evergreens, broad-leaf deciduous, and broad-leaf evergreens, on water yield at the watershed scale. This research uses the SWAT (Soil and Water Assessment Tool) model to assess water yield. Plantations development of needle-leaf evergreens, broad-leaf deciduous and broad-leaf evergreens had no negative effect on water yield. Plantations development of needle-leaf evergreens, contributed maximum water from the base flow and lateral flow in a 60% forest area on a watershed area. A 40% increase in broad-leaf deciduous in the watershed contributes to an increase in water system from surface flow. The results of this study are expected to become a consideration in policy making related to the development of plantation forests at the watershed scale.