Native Cherry ?

The native cherry tree of the Pacific Northwest, including Washington state, is the bitter cherry 

(Prunus emarginata), a small tree or shrub with white flowers and small, red, bitter-tasting fruit. 

Distribution: Bitter Cherry is found from southern British Columbia to southern California along the coast through the Cascades and Sierra Nevada; east to the Rocky Mountains of Idaho and Montana, and in isolated communities in Wyoming, Utah, Arizona and New Mexico.

Habitat:  Bitter Cherry trees may be found in moist, second growth forests, often along streams, which is where these trees are located at the end of Bowthorpe. 

From PNW Website 

From PNW

Bitter Cherry in wet area under big trees.