The Arbor Day Foundation has an excellent interactive poster demonstrating trees’ impacts on stormwater management.
“Rain refreshes the land and nourishes the green landscape. But as houses, stores, schools, roads and parking lots spread and natural tree cover is lost, so is the absorbing effect of vegetation and soil. The welcome rain becomes costly stormwater runoff. Without the benefit of trees and vegetated infrastructure, waterways are polluted as oils, heavy metal particles and other harmful substances are washed away. Fish and wildlife suffer, drinking water becomes expensive or impossible to reclaim, property values are reduced, and our living environment is degraded.”