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• Every 1,000 urban trees we plant in the Northwest today will save our region more than a million dollars in stormwater management, pollution abatement, and energy costs. (Source: Center for Urban Forest Research, Davis, California)
• A typical tree produces about 260 pounds of oxygen each year. Two trees can supply a person’s oxygen needs. This is a conservative estimate based on the average annual oxygen consumption for a person at rest at 20 degrees Celcius and at standard pressure is an average of 400 pounds a year. (Source: David Nowak, USDA Forest Service, Syracuse, NY)
• Each year, the average yard tree cleans 330 pounds of carbon dioxide from the atmosphere through direct sequestration in the tree’s wood and from reduced power plant emissions due to cooling energy savings. (Source: Center for Urban Forest Research, Pacific Southwest Research Station, USDA Forest Service, Davis, California) City trees are fifteen times more capable of reducing carbon in the atmosphere than rural trees. (Source: ENN “Urban forests make environmental and economic sense,” Thursday, April 11, 2002) To calculate how much carbon dioxide your household generates, check out this carbon dioxide calculator provided by The Climate Trust.
• Trees contribute to neighborhood livability by reducing city noise and glare, and by calming and slowing traffic.
• Trees improve habitat for endangered fish, migratory birds, and other wildlife.
• Trees stabilize soil, reduce erosion, and mitigate flooding.
• Each urban tree with a 50-year lifespan provides an estimated $273 a year in reduced costs for air conditioning, erosion control, stormwater control, air pollution, and wildlife shelter. (Source: City of Portland, Oregon)
• Trees provide us with fruit and nuts. They also provide wood and paper products. Oregon's wood and paper products are sold in all 50 states and about 40 foreign countries. Oregon leads the nation in lumber production by a wide margin. Oregon also manufactures newsprint, printing paper, photocopy paper, egg cartons, and wood residues used to make resins, glues, cosmetics, and certain plastics. (Source: Oregon Forest Resources Institute)
• An average tree absorbs ten pounds of pollutants from the air each year, including four pounds of ozone and three pounds of particulates. A medium-sized deciduous tree in the Northwest removes pollutants from the atmosphere and reduces emissions of air pollution at an average savings of $1.89 per year in an urban environment. Over the tree’s estimated 40-year lifespan, each tree will save about $75.60 in reduced and removed air pollutants. (Source: Center for Urban Forest Research, Pacific Southwest Research Station, USDA Forest Service, Davis, California)
• The average tree cover in the Willamette/Lower Columbia Region in 2000 was 24 percent, down from 46 percent in 1972. This 24-percent canopy removes 178 million pounds of pollutants annually, at a value of $419 million a year in healthcare and other costs. The 1972 46-percent canopy cover would have removed 315 million pounds of pollutants annually, at a value of $741 a year to society, representing a loss of $322 million dollars. (Source: American Forests)
• Shade from trees can cool buildings up to 20 degrees in the summer. (Source: City of Portland) One large deciduous tree planted within 60 feet of the west side of an average-sized home in the Northwest reduces carbon dioxide emissions that contribute to global warming and lowers the home's cooling costs by about $444 over a 40-year lifespan, assuming an average cost of $.0941 per kwh. (Source of calculation formula: Center for Urban Forest Research, Davis, California.)
• The leaves of a mature tree intercept an average of 760 gallons of rainfall a year. Each tree that lives about 40 years saves $10 a year in reduced water flow treatment and control in the Portland metro area. (Source: Trees for Green Streets, Metro)
• Unlike some other investments that depreciate, a tree's value increases with each passing year. Trees increase home property values 7 to 21 percent, depending on the number and size of the trees. (Source: City of Portland)