Improve Portland’s Tree Code to Save Important Trees
Portland is generally a pretty progressive city, and that’s one of the reasons that many of us choose to live here. Another reason is its natural beauty, much of which is supplied by trees. But today, no tree—even if it’s huge, healthy, native, and majestic—is safe anywhere in the city due to currently out-of-control development rules that favor developers and their bottom line.
Portland’s relatively new tree code (Title 11) has proved to be inadequate in that it currently does not require that any tree in a development situation be preserved. The code currently allows for the removal of 2/3 of a property’s trees, with just 1/3 retained. However, for a measly $1200 (maximum) “fee in lieu of preservation” per tree, a developer can destroy the third if they’re in his way, no questions asked. Moreover, properties less than 5,000 square feet (your average 50 x 100-foot lot) and commercial/industrial zones are completely exempt from the code.
According to city records, tree removal permits for demolition and new construction during one month—August 2015—revealed that only 13 of 53 trees that were greater than 24 inches DBH (trunk diameter at breast height) were spared the chainsaw. Several of the trees destroyed during that month were greater than 42 inches DBH. Granted, one month is a small sample and not an average, but the point is that we cannot afford to lose any more quality trees. Comments during a recent Oversight and Advisory Committee (OAC) meeting revealed that Portland’s tree canopy is likely shrinking.
Speak up for voiceless trees and wildlife!
Two proposals—one from Urban Forestry’s office and one from the Bureau of Development Services—will be reviewed by the Planning and Sustainability Commission (January 12) and by the Urban Forestry Commission (January 21). Both proposals seek protections only for trees greater than 48 or 50 inches DBH and they are lax in other ways. (The January 12 meeting
begins at 12:30 pm and testimony will likely start at 2 pm)
Trees over 48 inches DBH are very rare in Portland. For example, in Wilshire Park, which is home 
to 346 trees (most of them mature Douglas-firs), we found that only two measured 48 inches DBH or just slightly greater. Under either proposal and if these trees were in development situations, only two trees of the 346 trees would be safe.
Large, mature trees are extremely important to wildlife for food and shelter, and they provide myriad other environmental benefits and as such ought to be protected. But we also need to recognize that we will have much fewer large trees in the future if developers are allowed to remove any tree that’s in their way now.
Follow the Plan
The 2035 Portland Comprehensive Plan clearly states, “potential adverse impacts of development must be well understood and avoided where practicable. These policies also call for an evaluation of design alternatives to minimize negative impacts, and the use of mitigation approaches that fully mitigate unavoidable impacts.” It also recommends preserving Pacific Northwest native
trees.
Title 11 does not provide incentive to keep trees, nor does it require consideration of design alternatives. A paltry mitigation fee cannot fully mitigate the loss of ecologically and aesthetically
significant trees that are part of our neighborhoods and region, and whose loss permanently impacts people and devastates wildlife. We must first seek to avoid, then minimize, and then, and only as a last resort, mitigate.
Mitigation as a last resort
When healthy, mature, life-giving trees are eliminated, it’s impossible to replicate their benefits. How can we possibly compensate for the sudden loss of something irreplaceable? What happens to exhausted migratory birds that counted on a certain trees as stopover habitat? Planting a few sapling trees cannot supply the lost cover and food for wildlife any more than they can supply the shade, oxygen, and carbon sequestration provided by a mature tree. The graph at the end of the OAC’s recommendations shows how terribly long it takes for young replacement trees to begin to supply benefits (and some never will). Plus, the replacements are often smaller species and/or planted off site, possibly miles away, so the benefit to local wildlife is nonexistent.
All trees are not created equal
Preserving the towering, big-canopy trees that supply the most environmental and public health benefits like cleaner air and water makes perfect sense, but we also need to look at species as well as diameter. While large trees—especially conifers—are immensely important for wildlife, shade, and storm water mitigation, studies have concluded that certain tree types are enormously supportive of native insect herbivores, which provide essential food for wild species like birds.
But many valuable native trees do not grow large. In fact, some only grow to 20 inches DBH at maturity, at most. And others are so slow growing that even at age 50 they would not have the girth that would be considered “large.” Native oaks support the most insect herbivores (over 540 species of butterfly and moth, alone), but oaks—especially our beloved Oregon white oak (Quercus garryana)—are very slow growers and to reach 30 inches DBH could take well over 100 years, depending on conditions. Native wild cherries (genus Prunus), willows (genus Salix), birch (genus Betula), aspens/cottonwood (genus Populus), and pines (Pinus spp.) are other highly productive species for insect herbivores that in turn support other wildlife. With the exception of ponderosa pine and cottonwood, all of the faster growing trees mentioned do not grow to a large diameter.
We also need to consider the repercussions of removing trees that were, for example, preventing erosion on hillsides, providing a windbreak, or protecting nearby vegetation.
What do other progressive cities do?
Some cities have adopted regulations that could serve as a model for Portland. Vancouver, B.C. requires that all new houses be built on existing footprints; they do not allow a modest house to be replaced with a 3,000 or 4,000 square foot home that no one needs and does not contribute to urban density. Lake Oswego requires that “Removal of the tree will not have a significant negative impact on erosion, soil stability, flow of surface waters, protection of adjacent trees, or existing windbreaks” and “Removal of the tree will not have a significant negative impact on the character, aesthetics, or property values of the neighborhood. The City may grant an exception to this criterion when alternatives to the tree removal have been considered and no reasonable alternative exists to allow the property to be used as permitted in the zone. In making this determination, the City may consider alternative site plans or placement of structures or alternate landscaping designs that would lessen the impact on trees, so long as the alternatives continue to comply with other provisions of the Lake Oswego Code.”
How you can help
If you believe that Title 11’s lack of protection for trees and its wholly inadequate mitigation provisions need to be changed, I encourage you to offer comments or simply show your support at either of the above mentioned meetings. I attended and testified at several of the OAC meetings this past fall and I can tell you that they do listen and consider sensible comments. My suggestion that the value of small and/or slow-growing native trees be considered in their recommendations did make it into their memorandum.
If you can’t make the meetings you may send written comments (with your name and address) via email to: PSC@PortlandOregon.gov and trees@PortlandOregon.gov
Suggested comments:
♦ Remove the Title 11 exemptions for small lots and commercial and industrial land
♦ Avoid destruction by requiring design alternatives to cutting
♦ Require a site review process with public involvement for trees greater than 20 inches DBH.
♦ Require mandatory posting/public notice and at least a 30-day period before any tree greater than 20 inches DBH is cut down
♦ Consider tree species, giving special consideration to the superior ecological value of Willamette Valley native trees, no matter their size
♦ Use mitigation as a last resort, adding an inch-for-inch protocol, at least $300 per inch for healthy trees greater than 20 inches DBH, and $500 per inch for native species, and changing the 1/3 preservation rule to preservation of caliper inches of trees on site.
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