TriMet employees Jeff Johnson, a landscape maintenance professional with an arborist background, and Sean Batty, a landscape architect, were two of the biggest advocates for the presence of trees on the platforms. While the tree design was basically in place by the time Jeff came on board, he had a several goals in mind for the project overall:
- Varying tree species.
By varying the types of trees, TriMet could monitor which species were the most successful while allowing riders an easy way to visually differentiate the platforms .
- Making riders happy and comfortable.
The improvement of the lightrail system carried a significant cost — TriMet wanted to ensure that system patrons would be satisfied with the new platform design and knew that trees were a priority for Portland residents.
- Reducing noise pollution
The City of Portland, well-known for being friendly to the environment, has a requirement that more trees be planted than are removed. (Their canopy cover is somewhere above 26%, and they arecurrently working to increase it to 33%.) But they knew that tree planting alone wouldn’t be enough. They had to pay attention to how to plant them — specifically, pursuing design strategies and technologies that would provide them with conditions suitable to long-term growth and overall health. That’s where the Silva Cell, which was introduced to Johnson and Batty by a county partner, came in.
In addition to using the Silva Cell to provide adequate soil volumes on the lightrail platforms, Jeff and Sean decided to write their own contract with a plan for early tree procurement to local nurseries. The early procurement contract allowed them to inspect the trees prior to planting and ensure that the 3” caliper trees they intended to plant were healthy and good quality.
The trees on the seven light rail platforms are doing great, and TriMet has received a lot of positive rider feedback. Trees on light rail platforms face comparable stresses to trees planted on streetscapes — heavy pedestrian traffic, oceans of paving, and trash from daily wear and tear. Traditional transit platforms can be cold and sterile; by adding trees as a natural element the experience for riders is dramatically improved. Bolstered by appropriate rooting volumes, TriMet has created conditions for these trees to thrive, enabling them to act as windscreens, shelters, and generally desirable spots to wait for the train home to ferry you away. Similar transit systems should consider how including trees in their design plans can encourage ridership by making platforms more appealing, effective and comfortable for patrons.
Images: Jeff Johnson (thanks!)