Meine van Noordwijk began by tracing the evolution in our understanding of forests and water. For a long time, the general view was that forests are good for water and all problems can be fixed by planting trees. As the limitations of this understanding became apparent, the balance swung towards a view that having more trees leads to less water being available for other uses. Now, however, we have moved to a more nuanced understanding – how trees and forests affect water availability depends on the context. The priority then should be to have the right trees in the right place for the ecosystem services that we want.
There are several properties of forests that affect water availability including tree rooting depth, canopy density, leaf litter on the surface, soil sealing and soil structure. These factors also interact with climate and human activities in river catchments. The extent to which the flow in a river changes day to day is a simple way to assess how greatly the forests, and other land uses in the catchment, buffer the river from rainfall. Therefore, the specific impacts on water of how forests are managed need to be considered in the overall context of the catchment and how people interact with it.
The second part of the webinar focused on payments for environmental services (PES) schemes. There are many examples of schemes where water users pay for forests to be conserved, as well as some examples of payments for reforestation or for retiring or improving agricultural land. Users typically pay a surcharge on their water bill, which contributes to providing remuneration for these functions in upper parts of river catchments to protect drinking water. Such schemes are most common in the Americas, with the long-running scheme in Costa Rica, whereby landowners are paid to protect forests, being a well-known example.
The expert presentations were followed by discussion with participants, moderated by SINCERE project coordinator, Georg Winkel, including questions from partners leading the SINCERE Innovation Actions. The ideas and frameworks for thinking about the relationships between forests and water have given them inspiration for developing their own innovative mechanisms to support forest ecosystem services. This event was a Green Week partner event.