There’s lots of evidence to suggest that landscapes with trees help to reduce flood risk, compared with open terrain. Trees and the thicker vegetation that develops around them if livestock are excluded increase the ground’s roughness, making it harder for water to flow over the surface. Just as the pine forests in the Alps protect mountain villages from avalanche, trees can also act as a brake to earth and rock released in a landslide. Their roots help water to get into the ground more quickly and to penetrate to greater depths, as well as physically binding the soil in place.
