King County to start forest restoration project in Cougar Mountain Park

King County Parks announced this week that they will be starting a forest restoration project in Cougar Mountain Park. This project entails " thinning small areas of red alder and then replanting the areas with a diverse mix of conifers." This is known as "gap treatment and will create much needed 2-5 acre gaps in the forest canopy, north and south of the Clay Pit Road. There will be approximately six separate gaps, for a total of 17 acres of gap in the Alder canopy. The new gaps in the canopy will allow light to reach the forest floor for the newly planted conifers and the downed trees, which will be left onsite, will provide nutrients to the soil.

Why is forest thinning important? According to King County, creating canopy gaps allows light to reach the forest floor, supporting the growth of new slow-growing conifer seedlings. While some conifer species are quite shade-tolerant and will survive underneath a large canopy, their growth will be slowed by the shade. By introducing conifer seedlings to the forest, foresters can shift a homogenous broadleaf forest to a mixed broadleaf-confier forest and increasing forest biodiversity.

Many of the alders in Cougar Mountain Park are reaching an age where they will start to die off. In order to ensure the maintenance of a healthy forest in this area foresters are trying to support faster growth of long-living conifers through this thinning project. This project will begin later this March or early in April. Informational signs have been posted as trailheads, though thinning will take place away from trails and will not affect them. For more information visit: https://www.kingcounty.gov/services/parks-recreation/parks/parks-and-natural-lands/natural-lands/forest-stewardship.aspx

“A New Forest” signs are placed at trailheads by King County Parks in Cougar Mountain Park and provide information on the Alder thinning project.