Many of our urban forests are being invaded by a force of small green beings that are invisible to the untrained eye.
The diverse plants that keep our parks healthy are being bullied out of their neighborhood by a host of invasive species. These non-native plants grow at a much faster pace, having a destructive effect on the soil and plant life around them.
Invasive plants may look just as green and pretty as any others, but if allowed to spread, they will gradually ruin the local habitat for native birds and animals, forcing them out of sight. A lack of diversity means that any new pest or disease could wipe out entire areas of vegetation.
English ivy is one of the most familiar invasive plants. Its evergreen leaves cover the ground so densely that seedlings and other plants don’t get enough light to grow. But ivy doesn’t protect soil from erosion very well. We’ve grown used to seeing it in urban areas where it can add some green to otherwise stark building environments. But in the forest, it will literally choke the life from trees as it engulfs them.
“It’s better than concrete, but not a lot better,” said urban forester Kathy Sutalo.
One of the most tenacious of the invaders is knotweed, a plant so powerful it can break through pavement and buildings. Once its roots take hold of the soil, they grow so densely that other plants don’t get any room to grow. Knotweed also is nearly impossible to kill. Simply chopping this plant down will cause it to multiply next season, and the only way to get rid of it for good is to poison the root, Sutalo said. It often takes several years to clear an area.
Other common invasive plants that cover a lot of ground are Himalayan blackberry and Scotch broom.
TAKING BACK TITLOW
Faced with this challenge, government agencies and community groups have decided to coordinate their resources to continue restoring one of Tacoma’s signature parks this spring.
At Titlow Park – at the base of Sixth Avenue in Tacoma – crews from the Washington Conservation Corps cleared out overgrown patches of blackberry. Then, a team of volunteers moved into the area, took out the roots and replanted the park with native plants.
The restoration would not have been possible without the paid crews, said Joe Brady, natural resources manager for Metro Parks Tacoma. They are publicly funded through the Urban Forest Restoration Project, administered by the state Department of Natural Resources.
Community volunteers of all ages help take care of neighborhood parks by holding regular work parties to clear out invasive species. Each team is led by a natural area steward, a specially trained volunteer who coordinates the work.
Titlow Park previously didn’t have its own volunteer steward, so work until now has been dependent on limited staff, grant-funded crews and one-day work parties. That will change this year, with the arrival of a steward who will help take care of the park once her training this month is complete.
In 2005, the conservation group Forterra teamed up with the City of Tacoma and Metro Parks to create Green Tacoma Partnership to facilitate more of these collaborative projects.
Through the partnership, Forterra offers citizens the training they need to take part in conservation efforts all over the city. Meanwhile, Metro Parks Tacoma helps coordinate volunteers and also provides equipment and resources.
The partnership also attracts funding from donors and helps with outreach.
Brady said there aren’t enough volunteers to help fight invasive plants in all of Tacoma’s parks, and he hopes more people will get involved through the Green Tacoma Partnership.
“Urban forests are at war with invasive plants every day,” Brady said. “We’re so grateful for the dedicated community members who are fighting with us to protect these vitally important resources.”
Join the fight: Volunteering is a fun family activity, and more people are needed to fight back invasive plants in parks. Visit metroparkstacoma.org/parks- appreciation-day-chip-in to sign up as a Parks Appreciation Day Volunteer on April 20. There are opportunities throughout Pierce County.
Lead the charge: On March 30, Forterra will host a training seminar for new natural area stewards. To learn more, visit forterra.org/events/green_tacoma_partnership_steward_orientation.
Celebrate victory: Bring your children and their friends, and come enjoy our great urban forests. You’ll find all kinds of fun activities at discovertheforest.org/what-to-do.