Water temperature affects all physical, chemical and biological process within the freshwater environment. Most aquatic species have a specific temperature range they can survive in. Salmonids require temperatures between 5-15 degrees, however over 22 degrees for a sustained period of time can be lethal.
Historically, rivers across the UK where more densely shaded, however majority of this tree cover has been lost resulting in rivers lack shade and cover. Riparian tree cover is very important in reducing local stream temperatures, up to 3 degrees in summer months and maintain a more constant water temperature.
Therefore it is important to increase the amount of riparian tree cover. There are also additional benefits to tree planting such as providing food, habitat and maintaining more natural stream functioning.
Read more from the Woodland Trust’s Keeping Rivers Cool manual.