When my kids were little, we read the Caldecott-Award-winning storybook that offers a child’s view of why “a tree is nice.” With Arbor and Earth Day coming up April 22nd, it’s timely to review the many virtues of trees.
Trees are very nice. They fill up the sky. They go besides the rivers and down the valleys. They live up on the hills. Trees make the woods. They make everything beautiful. – Janice May Udry
In its frontier days of breakneck growth and timber clearing, Portland was dubbed Stumptown. About 160 years on, the City aspires to the nickname ‘Treetown’ for grown-up economic and environmental reasons.
As every realtor knows, trees boost property values. How much? According to one study, each large front-yard specimen increases a home’s sale price by 1 percent. Neighborhoods with good tree cover enjoy a 6-9 percent price edge over those without. Lower income communities see the highest gains from tree planting and landscaping, by the way.
Trees also reduce homeowners’ utility costs. Two 25-foot trees on the west side of a house result in yearly savings of about 36 percent on cooling bills and 7 percent on heating bills. When whole cities commit to trees, everyone benefits. A good canopy cover lowers both summertime highs (by 5-9 degrees Farenheit) and demand for air conditioning.
Urban tree canopies also help preserve our natural capital, removing greenhouse gases and pollutants from the air. By one estimate, planting 30,000 trees a year for five years will absorb 75,000 tons of carbon dioxide at a cost of just $34 per ton. By another, the tree cover in the Willamette and Lower Columbia Region removes 89,000 tons of pollutants annually.
As they clear the air, trees also clean our water. Urban canopies absorb and filter storm water – to the tune of about 845 gallons per year per tree – that would otherwise flood sewers and pollute waterways. They also help recharge groundwater supplies.
As recently as 1991, 6 billion gallons of untreated sewage and storm water flowed into the Willamette and Columbia Rivers every year. Facing an Environmental Protection Agency order, the City built new “grey” infrastructure like a $1.5 billion wastewater storage tunnel. Over time, Portland has given higher priority to building our green infrastructure, a more cost-effective approach to protecting the watershed.
The City launched the Grey to Green program in 2008. Tree planting is one of 6 key activities to improve water and air quality, wildlife habitat and livability. The other pillars of the program are acquiring and protecting open spaces, constructing green street planters, building eco-roofs, controlling invasive species and restoring natural vegetation.
As part of Gray to Green, Portland runs an annual “treebate” from September 1 to April 30. If you plant a tree during this period, your water and sewer utility bill will be credited for half the purchase price up to $15 for small species, $25 for medium species and $50 for large species. Click here for details. Local non-profit Friends of Trees partners with the City in the treebate, helping homeowners to choose, buy and plant.
In part as a result of these efforts, Portland can rightly be called Treetown. Covering about 30 percent of the city, our urban forest canopy made the top 10 list compiled by conservation group American Forests a few years back. But the City isn’t resting on its laurels. Much of the canopy we enjoy today is the legacy of previous generations and needs to be restocked as it reaches maturity. Its quality can also be improved. There is not enough diversity (for example, maples and elms are overrepresented and vulnerable to disease and pests) and we need more species that will be large at maturity.
You can check out the health of the canopy in your neighborhood here. If your area doesn’t have a tree report card yet, you can help organize one. Across Portland, community volunteers have worked with the Parks & Recreation Department to inventory neighborhood trees and develop improvement plans. There’s always work to be done – pruning, planting and so on.
In addition to their economic and environmental value, trees provide these social benefits:
- Improved health and psychological well-being
- Privacy, sound barriers and wind breaks
- Lower crime rates
- Stronger community ties
- Recreation
- Aesthetic pleasure
Believe it or not, these intangibles can be quantified with hedonic pricing, a method commonly used to calculate the effect of environmental features on the market price of housing. I suspect the hedonic value of Portland’s urban canopy is a factor in the tide of migration to the city and rapidly rising home prices.
Though my head understands the need for such valuations in public policy and commerce, my heart doubts that you can put a price on our urban canopy – or put the appeal of trees into words, for that matter. Maybe that’s why the storybook comes to mind. Maybe there’s no better testament to their power than the childlike wonder of A Tree Is Nice.