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Bark beetle tree infestations cause I-5 closures throughout May

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NORTH SEATTLE — An infestation of bark beetles in trees along Interstate 5 will cause intermittent lane and ramp closures throughout the month.

According to the Washington State Department of Transportation (WSDOT), maintenance crews reported the unhealthy trees by the side of the highway to an arborist team within the Northwest Region’s landscape architecture office. This specialized team preserves, maintains, and manages trees on state roads.

Together with the Department of Natural Resources, the team determined that the trees were infested with a deadly species of bark beetle – Ips pini.

Treatment of the infested trees is not effective, so the best option to reduce beetle populations and limit the spread to healthy trees is removal. Experts have determined that 126 trees need to be removed in the north Seattle area, with most along I-5 northbound.

The tree removal will result in lane and ramp closures of I-5 throughout the month of May:

First Closure: May 13-16, 9 p.m. to 4 a.m.

  • Northbound I-5 off-ramp to NE 85th St.
  • NE 70th St. on-ramp to northbound I-5.

Second Closure: May 16-17, 9 p.m. to 4 a.m.

  • Northbound I-5, right lane, from NE 42nd St. to just south of NE 50th St.

Third Closure: May 20-23, 9 p.m. to 4 a.m.

  • Northbound I-5 off-ramp to NE 85th St.

Fourth Closure: May 23-24, 9 p.m. to 4 a.m.

  • Northbound I-5, right lane, from NE 42nd St. to just south of NE 50th St.

The WSDOT hopes to use this opportunity to “establish a more diverse and resilient roadside canopy on the I-5 corridor in North Seattle. Landscape architects and arborist specialists are developing a replanting and restoration plan for the area.”

The kind of trees replanted will depend on environmental resilience, resistance to pests and diseases, pollinator habitat, cultural significance, and aesthetics. According to WSDOT, replanting will likely happen in the fall and winter of 2024 and 2025, though the process can be long and it will take a while for the new trees to grow fully.

For more information on the closures and how to spot an infested tree, visit the Washington State Department of Transportation blog.