One-third of that tree canopy is on public park lands. Eighty percent of Seattle land is privately owned.

Good news for tree-loving homeowners: The presence of trees on your property increases home value. Studies suggest an increase of 5-15 percent.

Equally good news for tree-loving shopowners: Trees in a shopping district attract customers, and may increase the price shoppers are willing to pay for goods, according to studies conducted by Kathy L. Wolf, PhD, at the University of Washington's Center for Urban Horticulture.

Trees cool the environment with their shade. This used to be bad news to sun-starved Seattleites, but in hotter, drier years of late, has become good news.

Trees remove carbon dioxide (cause of the "greenhouse effect") from the atmosphere and store it as cellulose. Approximately 800 million tons of carbon are stored in U.S. urban forests.

Trees reduce flooding and decrease the need for water filtration.