Forests play a vital role in sustaining water resources and aquatic ecosystems. Forests act as giant sponges, soaking up rainfall during wet seasons and releasing it slowly during drier times. Forests can also help reduce the severity of flash floods downstream through the sponge effect and by blocking the path of the water with tree trunks, branches and other forest litter. Forests provide natural filtration and can help improve stream quality and watershed health by decreasing the level of storm water runoff and pollutants that reach local waters. Trees also absorb nutrients and pollutants and transform them into less harmful substances. Forests maintain high water quality by minimising soil erosion and reducing sediment. In contrast, deforestation often increases soil erosion that results in higher sediment concentrations in the runoff and siltation of watercourses. Furthermore, Forests recycle rainfall and groundwater to support continental-scale and intercontinental-scale hydrological cycles. Deforestation and forest degradation in one area can have an impact on rainfall patterns in other parts of the world.
Forest disturbance can have a profound effect on the hydrologic, geomorphic and ecologic processes. Disturbance can include both natural (e.g. drought, disease, wildfire, storms) and human (e.g. Land conversion, agriculture, timber harvesting). Natural disturbances are becoming more frequent and catastrophic due to climate change. This, together with growing human disturbance will affect the quality of water and its availability.
We encourage schools to examine the relationship between forests and water and to investigate the challenges in maximising the wide range of multi-sectoral forest benefits (domestic, agricultural, industrial, and ecological) without detriment to water resources and ecosystem function. Most importantly, we encourage schools to come up with practical solutions that help ensure high water quality and help raise awareness about the importance of protecting our forests.