Forests provide multiple ecosystem services, with relevance for the ones related to water. It is widely accepted that forests greatly influence the water cycle, promoting evapotranspiration, improving infiltration, reducing surface runoff and consequently soil erosion, although sometimes at expenses of a reduction in total water yield. In fact, forests are targeted for several measures to restore freshwater and land ecosystems, conserving biodiversity and at the same time improving the revenues of landowners, especially if Payments for Ecosystem Services (PES) are in place. However, the environmental effectiveness of these measures is not always acknowledged, especially due to the lack of local studies. Therefore, the objective of this presentation is to gather information based on modelling exercises applied to case-studies in Portugal, in which forests influence the provision of ecosystem services related to water in terms of quantity and quality. First, the results from an econometric model based on spatial variables applied to continental Portugal will be presented. Results suggested the existence of a positive and significant effect of local forest cover on water treatment cost savings of 0.056%. Secondly, scenarios of afforestation were simulated in SWAT (Soil and Water Assessment Tool) for two watersheds of northern Portugal. Results revealed that forests have a positive role on the regulation of water, in particular for the scenario of native deciduous type of trees, such as oak. Moreover, forests influence water quality, in terms of less nitrates in the river, and less soil erosion, when compared to a scenario of agricultural expansion. Lastly, a SWAT application in a small watershed in Central Portugal with scenarios of afforestation vs. fires, showed that soil erosion protection and water quality regulation provided by forests might be negatively affected by fire occurrence. Overall, further work should be done to consider fire risk over PES schemes applied to the Mediterranean forest.info:eu-repo/semantics/publishedVersio
