Independence Pass

Control tree shows 23 annual rings between the 1472 and 1495 narrow rings, while the tree in the We tephra-fall zone shows only 20 rings. The series of missing and narrow rings starting with the 1482 ring were caused by tree injury during fallout of layer We.
-- Yamaguchi, et.al., 1986

At the end of the trail is an excellent view of Mount St. Helens and Spirit Lake. In good weather you can see part of the growing lava dome within the crater (1986 height, 918 feet). Along this trail is a cut tree trunk that shows tightly clustered growth rings corresponding to the years A.D.1801-5 (effects of eruption of pumice of the T tephra in A.D. 1800; Yamaguchi, 1983). Along the trail the blast deposit can be recognized by its gray color. It contains gravel-to sand-size rock fragments from the edifice of Mount St. Helens, pieces of slightly vesicular gray dacite from the cryptodome, and fragments of shredded wood. The hike is an opportunity to explore the diverse effects of the blast on both large and small trees. Small trees buried under the winter snow remained untouched. Very few large trees were transported or reoriented after they fell. Standing trunks on and behind the ridge to the north indicated that the flow was diffuse enough to loft over them but still snapped off their crowns.

-- Excerpt from: Doukas, 1990, Road Guide to Volcanic Deposits of Mount St. Helens and Vicinity, Washington: USGS Bulletin 1859, 53p.