By Midge Pierce
Billed as the Grand Reveal, a five-year, record-breaking inventory of more than 218,610 street trees illustrates the magnificence of Portland’s green rooftop as well as the great risks it faces.
Portland currently enjoys the legacy of previous generations’ transformation of a pioneer clear-cut known as Stumptown into today’s Treetown. That legacy has now reached its maturation and must be restocked, according to findings released at Parks & Recreation’s annual Tree Summit.
The glorious canopy that cools us, improves our air and water quality and stabilizes our slopes is endangered by disease and pests, declining budgets, deferred maintenance and the squeeze of demolition. Despite challenges, our urban forest is the envy of other cities.
To keep it that way, speakers urged citizens to be proactive in planting and persuading the City to enact stronger preservation measures.
Canopy analytics indicate that neighborhoods shaded by trees are 15 degrees cooler in summer heat. Market data shows trees raise property values as much as $7000 per tree.
Portland City Forester Jenn Cairo told residents to think big and plant in greater numbers, diversity and size. Large trees live longer and have the biggest health benefits including decreases in lung problems like asthma, fewer hospitalizations and lower medical costs.
“A block of ten trees can make you feel ten years younger,” according to tree activist Jim Labbe.
The green gifts of trees are threatened by Portland’s reliance on too few species such as maples and elms which are susceptible to pests and disease. SE Portland is most at risk.
When the bugs get here, the maple and elm-lined streets of our inner neighborhoods like Ladds Addition and Sunnyside will be hard-hit if not lost altogether, speakers warned.
Roughly one out of four trees in the area is a maple, valued for its lovely fall colors. Despite, or really because of their popularity, maples are no longer on the City’s approved list. Foresters prefer large trees such as oaks or, even better, broadleaf evergreens and conifers.
Mt. Tabor, with its Olmsted-designed park, is well-stocked with trees, but residents on the park’s residential slopes are the worst offenders for planting small, deciduous trees that offer the fewest benefits. “When the leaves drop, the benefits stop,” said a speaker.
Small, flowering trees like plums and dogwoods that are short-lived fail to offer lasting value. Foresters recommend more disease-resistant varieties like snowbells and hornbeams.
Another challenge is the expense to homeowners of street tree maintenance. Elsewhere, the norm is for cities to be responsible for street trees. Unless policies change, speakers called on neighbors to help neighbors and plant the right tree in the right place.
Education is a conservation key. It should include outreach to the Portland Bureau of Transportation which has leeway to remove trees when instead, sidewalks and streets could bend around them.
As public rights-of-way get tighter, trees are getting smaller. Planning, research and advocacy are needed, according to chief forester Cairo. “Good science makes good planning.”
Tree inventory staffer Jeff Ramsey said, “”It’s just as much a shame to lose space for trees as to lose the tree itself.”
With development pressures mounting, Mark Bello, of the Urban Forestry Commission board said, “Trees should come first, not last.”
To pay Portland’s tree legacy forward, speakers urged vigilance. “It takes a lifetime to get the services that the old trees offered.”
Portland residents were not always tree huggers, according to historian David-Paul Hedberg. He credits schoolchildren a century ago for planting seedlings along the park blocks. Although the poplars they planted have long-since died, planting efforts left a lasting impression that trees are the pride of Portland.
To see how the trees in your neighborhood are faring go to: portlandoregon.gov/parks/53181