Replanting Trees
To make room for the new Sellwood Bridge and the construction zone, more than 800 trees were removed. We’ve now planted more than we removed, and will continue to maintain them while they establish themselves. Replanted trees that did not survive their first year will be replaced with new trees.
Why did trees need to be removed?
The trees needed to be removed because they were unavoidably within the construction zone for approved project improvements. These included improvements to a half-mile long section of Highway 43 north and south of the bridge, landslide stabilization near the west end of the bridge, retaining walls and bridge piers. Some trees interfered with extension of the regional trail from S.W. Miles Street to the bridge, and removal of the fish passage obstructions at Stephens Creek. The new bridge and interchange are built to modern standards and take up more land than the existing bridge and interchange, which were very narrow by comparison.
Where were trees removed?
About half the trees removed were on City of Portland property (Butterfly Park, Powers Marine Park, River View Natural Area, and Willamette Moorage Park) and Highway 43 right-of-way. Other trees were on property owned by Riverview Cemetery and the Willamette Shore Trolley right-of-way. A few trees were on the east side of the river, either on private residential property or on the east river bank.
What types of trees were removed and what condition were they in?
An arborist hired by Multnomah County surveyed the condition of the trees before construction of the new bridge in the fall of 2011. The survey documented the general health and condition of trees greater than 6” in diameter that were identified for removal. Many trees were in poor or fair condition. Most of the trees were along the river and on the west side of Highway 43. Native species removed include Douglas Fir, grand fir, red alder, vine maple, Western hemlock, and yew. Non-natives and invasive species removed include English ivy, clematis, elm, English laurel, European white birch, holly, and Norway maple.
How many and what types of trees were replanted?
The City of Portland land use decision requires planting 1,516 trees and 1,773 shrubs within the project area. The plant materials are all native species selected from the Portland Plant List. Also, riparian tree planting occurred at Willamette Moorage and Powers Marine parks in association with stream restoration and historical fill removals.
The tree removal plan was addressed as part of the City of Portland’s land use review (a Type 3 Environmental/Greenway review), and as part of the "Non-Park Use Permit" for tree removals on city-owned land, including parks and city right-of-way.
The land use decision set the requirements for tree replacement and mitigation. The decision noted the size and quality of trees to be replanted.
Does the post-project landscape offer any environmental benefits?
English ivy and other non-native, invasive species were removed. Trees in poor condition were removed. All replacement trees and shrubs are native species. The replacement trees and shrubs will be cared for at least five years until they are established. Densities of the plantings are designed for full stocking and invasive species control, without crowding. Numerous shoreline areas previously without important native woody riparian cover (including existing buildings and pavement) will be restored to continuous vegetative canopy, which will improve streamside and habitat support functions.