Economic Values of a Healthy Urban Forest

Our urban forest is the lungs of Mercer Island.  It provides cleaner air and streams.  A healthy, functioning urban forest works better for storm and ground water cleanliness than any engineered solutions.  There is no up side to a loss of urban forest.  Every community that has made a decision to lose forest has been on the decline.

Trees:

• Improve property values; homes with significant trees are more desirable and have a higher resale value.
• Reduce air pollution by removing carbon dioxide from the air, reducing the greenhouse effect.  One acre of trees eliminates as much carbon dioxide from the air as produced from driving a car 26,000 miles!  
• Reduce storm water run-off costs by controlling surface and ground water runoff; cheaper and more effective than engineering solutions for water management.  Conifer trees act as giant umbrellas and protect the soil from the impact of rains drops Also through transpiration/expiration they prevent most of the water from reaching the ground.
• Reduce energy costs by shading buildings.
• Cool surrounding air by evaporation and transpiration.  Fewer trees mean more power use for air conditioning.
• Remove gallons of water from the soil.  
• Generally help stabilize hillsides, physically by their root structure and by the absorption of water from the hillsides.
• Higher tree cover yields a better Benthic Index of Biotic Integrity (BIBI) in streams.  According to the 2001 Annual Report for the City of Mercer Island "Mercer Island sites rank among the lowest countywide using this biological indicator."

Additionally there are social values to trees where the economic value is more difficult to determine.

• People heal faster when they can see trees.

• Trees improve mood.

• Trees calm aggressive driving and traffic.

• Worker productivity is improved when people can see trees.

• Trees attract shoppers in a business district.

• Trees increase the sense of community.

• Standardized test scores rose in children who moved from non-green to green environments.

International Forest Conservation Field Course 2003 is a link to interesting professional papers.  Topics include the following but they are all in the same document.  You need to scroll through to find the individual papers:

• DIVERSITY AND STATE OF FOREST ECOSYSTEMS IN THE PACIFIC NORTHWEST

• OLD GROWTH FORESTS OF THE PACIFIC NORTHWEST:  DEFINITIONS AND ECOLOGICAL CHARACTERISTICS

• HISTORICAL PATTERNS OF FOREST UTILIZATION AND THEIR LASTING IMPACTS

• NATURAL FIRE RETURN INTERVALS IN THE PACIFIC NORTHWEST

• LICHEN ECOLOGY OF THE PACIFIC NORTHWEST

• MARBLED MURRELETS AND OREGON’S COASTAL OLD-GROWTH ECOLOGY