This week, the Port began work on the first phase of a project to remove cottonwood trees growing beneath federally-regulated airspace at Portland International Airport. The site will ultimately be replanted with lower-growing, native plants. Although this first phase of tree removal took only a few days, the project is the culmination of years of planning.
Portland has a well-deserved reputation as a tree-loving city, from the iconic Forest Park to the steadfast efforts of local nonprofit, Friends of Trees. Cutting down trees is not something we take lightly. The Port was faced with a decision that was absolutely necessary to keep PDX operational well into the future.
The stand of cottonwood trees in question is located in a vegetated area within the economy parking lots. The trees lie below the regulated airspace for approaches and departures from PDX’s north runway. The trees were not yet to the point where they posed a flight safety risk, but they were beginning to penetrate other types of Federal Aviation Administration regulated airspace surrounding the flight paths. These areas are protected to prevent interference with instruments that guide approaching planes and to provide safe paths for planes should they experience mechanical difficulties.
The issue of trees encroaching on the airspace near the north runway has long been identified as a conflict that would eventually need to be addressed. In 2000, the trees were topped, providing an estimated 10-year window of protection for the airspace. Unfortunately, this was not a long-term solution. Topping trees compromises their health, making them hazardous to work around. Therefore, additional topping was not a viable option.
When master planning for PDX began through the Airport Futures process in 2007, removing the cottonwood trees in the economy lot was identified as an essential project to keep the airport operational well into the future. The Airport Futures process allowed the Port to work with the City of Portland and other stakeholders to develop a replanting plan that reflects the site’s status as an environmental zone and provides a sustainable, long-term solution that protects flight safety at PDX. When the site is replanted next fall, the trees will be replaced with more than 23,000 native shrub and small tree species such as vine maple, Oregon grape, red-flowering currant and native roses and willow. They will be planted around existing, lower-growing species of trees and shrubs that were left untouched.
While the loss of these trees is unfortunate, we have been able to complete the project in a way that was both as minimally invasive as possible and allows reuse of some of the logs and stumps for mitigation projects. The logging contractor hired by the Port used state-of-the-art equipment and technology to remove the trees, reducing the impact on the site and the amount of time during which the logging activity took place. Some of the logs cut for the project are being reserved to create turtle basking features at Port mitigation sites and some stumps will serve as large woody debris to create nearshore habitat.
The project is planned in phases to minimize site disturbance during wet weather months and to maximize the survivability of the new plants. It will take a little over a year for the site to be replanted and longer for it to become well-established. We will keep you posted on the site’s progress over time.
Artist's renderings of the site replanted with low-growing, native vegetation.