Forests and water: The value of native temperate forests in supplying water for human consumption

Temperate forests in the Southern Hemisphere provide ecosystem services of local and global importance such as internal nutrient cycling, soil protection, biodiversity conservation, climate regulation, and water supply. Under a scenario of global climatic change, water supply represents one of the most relevant of these forest environmental services. In this paper we estimated the economic value of Chilean temperate forests as they contribute to maintain fresh water supply, which in turn supports the production of drinkable water for cities. The study was carried out in the Valdivian Rainforest Ecoregion, in Llancahue watershed, which supplies fresh water to one of the main cities in Southern Chile. Using monthly time series from January 1995 to December 2003, we applied the change in productivity method to derive economic value estimates per cubic meter of water, per household, and per hectare accounting for changes in economic value during summer versus the rest of the year. The economic values per cubic meter were USD 0.066 and USD 0.025 for summer and rest of the year, respectively. The values per household equaled USD 15.4 in the summer and USD 5.8 for the rest of the year. The economic benefits per hectare of native forests were equal to USD 162.4 for summer period and USD 61.2 for the rest of the year.