Benefits of Urban Trees Trees Conserve Water and Reduce Soil Erosion Trees create organic matter on the soil surface from their leaf litter. Their roots increase soil permeability. This results in: Reduced surface runoff of water from storms. Reduced soil erosion and sedimentation in streams. Increased groundwater recharge that is significantly reduced by paving. Lesser amounts of chemicals transported to streams. Reduced wind erosion of soil. Without trees, cities would need to increase sewage and storm water drainage channels and waste treatment capacities to handle increased water runoff. « Return to the main page for the Benefits of Urban Trees.