By preserving and protecting mature trees on private property, on our streets and in our parks, we will continue to help renew and enhance San Diego's urban forest for future generations. Our urban forest provides us with many long-term environmental, social and economic benefits.

• A single large tree can release up to 400 gallons of water into the atmosphere each day.
• Tree foliage filters dust and can help remove toxic pollutants from the atmosphere. The foliage captures and removes a wide range of smog-producing compounds such as ozone, carbon monoxide, nitrogen oxide, airborne ammonia and some sulfur dioxide.
• Mature trees help to cool and freshen the air we breathe. Not only do they moderate the air temperature, but through photosynthesis, their leaves take in carbon dioxide and release oxygen for us to breath. A single, fully grown sycamore tree can transform 26 pounds of carbon dioxide into life-giving oxygen every year.
• Large trees remove 60 to 70 times more pollution than small trees.
• Mature trees improve our aesthetic environment, absorb noise, are traffic calming, reduce stress and crime, and create a peaceful place to relax or socialize.
• Trees provide positive mental benefits and healing qualities.
• Mature trees provide a sense of "home" to a neighborhood.
• Trees intercept rainwater aiding soil absorption for gradual release into streams, preventing flooding, filtering toxins and impurities, and extending water availability into dry months when it is most needed.
• Trees cleanse ground water as it filters through their root systems.
• The addition of trees and shrubs can increase property values by 10 to 20 percent.
• Water from roots is drawn up to the leaves where it evaporates. The conversion from water to gas absorbs huge amounts of heat, cooling hot city air.
• Trees help offset the "heat island" effect resulting from too much glass and concrete. A one-degree rise in temperature equals a 2 percent increase in peak electricity consumption.
• Urban neighborhoods with mature trees can be up to 11 degrees cooler in summer heat than neighborhoods without trees.
• One acre of trees produces enough oxygen for 18 people every day. One acre of trees absorbs enough carbon dioxide per year to match that emitted by driving a car 26,000 miles.
• Studies have proven for every dollar spent on maintaining trees, the public receives three dollars’ worth of benefits. It stands to reason that the public receives the most benefit from the preservation of larger mature trees and significant stands of forest.