The city of Sammamish announced Thursday it will remove 18 Douglas fir trees at Pine Lake Park due to laminated root rot, beginning the week of Oct. 10.

Sammamish Parks Director Angie Feser said the city contracted a certified arborist and assessor last March, which identified 18 of 225 trees of having the disease. Feser explained laminated root rot as a fungus that travels through soil that is not treatable nor preventable. She added that Douglas firs, which are not native to the area, are susceptible and compared the diseased trees to “zombies.”

“You look at them and they look fine, but they’re actually already dead,” Feser said. “The roots basically rot right at the base of the tree. Everything is fine until you get a good windstorm.”

Taking the trees down is not only a safety measure, Feser said, but also a means of slowing down the progression of the disease. The city stated in a press release it will replace the diseased trees by planting conifer and deciduous trees that are not vulnerable to laminated root rot.

Feser added the city will leave tree snags, or tall stumps, which provide food for birds and woodpeckers, as well as woody debris to decompose in the soil.

“It’s always sad to see trees fail,” Feser said, “but this is what we have to do to keep our tree canopy as healthy as possible.”