Living in a generally rural area, most of us probably don't give a lot of thought to urban forests. But as development expands the value of these resources to the environment will increase.
All across the United States urban forest resources are declining. The national urban tree deficit is the number of "average urban trees" we need in metropolitan areas to bring the tree canopy level up to American Forests conservative recommendations. These levels vary by land use, region and climate but are based on an average of 50 percent canopy cover.
By using these calculations, the current national urban tree deficit stands at 634,407,719. Numerous studies document the decline in urban forests, but why should we care?
The reasons for protecting and enhancing are many, but the strongest is the economic. American Forests (americanforests.org) recently released a study showing how the tree canopy of the Willamette/Lower Columbia Region in northeastern Oregon and southwestern Washington provides hundreds of millions of dollars in environmental and economic benefits, such as reducing stormwater runoff, energy usage and air pollution.
The report also shows the area's tree cover declined by 22 percent over the past 28 years, costing communities billions of dollars in lost benefits. If the tree canopy of 1972 had been retained, an estimated 58 million tons of carbon would not have entered the atmosphere. The lost tree cover increased stormwater runoff that costs an estimated $2.4 billion to manage and would have removed 138 million pounds of pollutants annually, valued at $322 million per year.
If the Portland region met the 40 percent average tree cover recommendation of American Forests, trees would provide about $1.03 billion in pollution removal and 146 million tons of carbon would be stored annually. Once again the soundest argument for environmental protection is economics.
So, how do we protect these resources? The simple answer is "plant a tree." But to succeed in the long run we need a combination of education, preservation, policy and enforcement. People need to be educated on the benefits of trees -- not just for toilet paper, but pollution reduction and energy savings.
Next, existing trees need to be preserved during development. Contractors need to be educated on the best management practices for protecting trees, and local ordinances need to be enacted and enforced to assure these BMPs are being followed.
Vegetation and landscape ordinances, which require the appropriate percent canopy cover, need to be adopted. Cities need to invest in urban forest management to establish existing inventories, determine areas in need of improvement, protect the health of trees and/or replace trees lost to disease and other natural causes.
In order for public policy to be successful it needs popular support, so contact your area planning administrator or commission member to express your views, then go plant a tree.
(Jim Chamberlin is a forestry technician with the Crow Wing County Soil and Water Conservation District.)
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