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Best of the Month | Check out how we’re using trees, plants, and other green infrastructure to help improve the health, safety, and welfare of people (and local zoo animals!)

A person walks in downtown Seattle, beneath several trees lining the sidewalk. Photo: SDOT.

At the Seattle Department of Transportation (SDOT), we believe environmental health should be improved for future generations through sustainable transportation. One of our major goals is to address the climate crisis through a resilient and environmentally-friendly transportation system. 

As part of our effort to help slow the pace of climate change, we’re working to reduce carbon emissions from our transportation system. We’re building more protected bike lanes and dedicated transit lanes throughout the city to make it easier and safer for you to walk, bike, roll, scoot, and take transit, when you can. Each of these travel alternatives generates less effects to the climate compared to traveling by car. The City of Seattle has also committed to electrifying our transportation system to reduce harmful emissions and make our city healthier and more resilient. 

Climate change disproportionately affects Black, Indigenous, and People of Color (BIPOC) communities. When considering these effects and how to work towards addressing them, equity and sustainability go hand-in-hand. Advancing a variety of environmentally-friendly, safe, reliable, and affordable travel options helps to better support all people in our city. We have a responsibility to always seek to leave things better than we found them so that current and future generations may be able to live healthier lives. 

A member of the SDOT urban forestry team gets ready to plant a tree.
This past spring, we planted 40 new trees in South Park. Read more in this previous blog post. Photo credit: Sherry Graham 

Managing trees, plants, and green infrastructure  

We also use trees, plants, and other green infrastructure to help improve the health, safety, and welfare of people who walk, roll, and bike, as well as to protect streets from the hot summer sun. 

Our landscape architect staff review each of our large projects, as well as other publicly or privately funded development projects in Seattle to promote retaining and protecting existing mature trees, and maximize shade and canopy cover over buildings, streets, and sidewalks.  

Street trees in Seattle’s Ballard neighborhood.
Street trees in Seattle’s Ballard neighborhood. Photo credit: SDOT 

Maintaining the health of street trees in a constrained urban environment is one of many challenges that our Urban Forestry team addresses with care and precision. Sometimes, a tree needs to be removed if it is dead or poses a public safety hazard. For example, when tree roots begin to outgrow their city environment, they can crack and eventually lift concrete panels on the sidewalk. This can cause challenges for everyone who uses the sidewalk, especially people who use mobility aids such as wheelchairs and other equipment to get around. If we need to remove a tree due to disease or to address safety issues, we have a commitment through the Levy to Move Seattle to plant two new trees.  

Our Urban Forestry team practices sustainability as an integral part of its day-to-day work. When crews prune or remove trees, they chip them into wood mulch, which gardeners use to help suppress weeds, conserve soil moisture, and keep soil temperatures steady. When possible, crews use battery-powered equipment such as chainsaws, hedge trimmers, and weed eaters in their maintenance work. This equipment generates less noise, does not need fossil fuels to operate, and requires less maintenance than gas-powered machines. 

Our irrigation crew has been working to upgrade our systems with new technology water flow meters and smart systems. These devices can remotely track when an irrigation system malfunctions and alert the team when there is a water leak. In the past, a system might have had a leak that could continue for days until it was reported or discovered by the crew. Now, we can turn off a system when we get an alert, which means a significant reduction in wasted water.  

Sometimes, we give our tree cuttings to help feed animals at the Woodland Park Zoo! 

A rhino at the Woodland Park Zoo munches on some silverberry in November.
A rhino at the Woodland Park Zoo munches on some silverberry in November. Photo credit: Jillian Weed 

On occasion, we coordinate with the zoo to pick up the cuttings instead of turning them into mulch. Zoo gardeners arrive in trucks and transport the material from our job site. A recent pruning job yielded silverberry, a plant that happens to be a favorite meal for rhinos! 

Staff from the Woodland Park Zoo pick up tree cuttings to take back to the zoo animals.
Staff from the Woodland Park Zoo pick up tree cuttings to take back to the zoo animals. Photo credit: Jillian Weed 

The clippings that SDOT gives to the zoo are called “browse,” and are sorted and fed to a wide variety of animals: giraffe, rhino, hippo, tree roo, pudu, tapir, mountain goat, farm animals, elk, warthogs, agouti, colobus monkey, orangutan, primate, sloth, porcupine, and wallaroo.  

To learn more about our strategy to reduce carbon pollution from our transportation and building sectors and make Seattle a national leader in fighting climate change, check out Seattle’s Climate Action Plan