Trees lower air temperatures by evaporating water from their leaves. Trees cut down on noise pollution by acting as sound barriers. A 1970 study found a 6 to 8 decibel reduction in noise per 100 feet of forest cover.
Tree roots stabilize the soil and prevent soil erosion.
Ornamental trees may need pruning, fertilizing, and watering in order to thrive. A tree doesn't reach its most productive stage of carbon storage until about ten years of age, and many urban trees don't survive that long. An acre of trees is expected to grow 4,000 pounds of wood per year, consuming 5,800 pounds of carbon dioxide and releasing 4,280 pounds of oxygen. Old, slow growing forests can consume more oxygen than they produce but young, vigorous forests tend to be the most efficient at absorbing carbon dioxide and producing oxygen. One million acres of forest are lost to city growth in the U.S. each year.