North Cascades National Park

Old-Growth Forest

Not so long ago ancient forests blanketed nearly all of the Pacific Northwest. Abundant rain and mild winters create the perfect environment for trees such as Douglas fir and cedar to grow very large and very old. These trees were so big that after loggers carved the first undercut wedge out of one of the old giants, a dozen or more timber workers could crowd into the gaping cut and pose for a picture. Early settlers would sometimes build roofs over hollow stumps to make homes out of them.

Most of these ancient trees are gone now, but in the wilds of the North Cascades you can still visit forests that have never been cut and still retain all the characteristics of old-growth forest.

At least some trees need to be 200-300 years old to be considered an old-growth forest; the forest must have a multi-level canopy; and there must be downed logs and standing dead trees, called snags.

Old-growth forests are characterized by a mixture of old and new, large and small, living and dead—all part of a dynamic ecosystem that is growing, evolving, and continually changing.

Centuries-old Douglas fir may tower over the forest floor, while younger shade-tolerant hemlocks struggle upward far below. Even after a tree dies from old age or disease it is still a vital part of the ancient forest ecosystem. Snags provide homes for dozens of birds and mammals. When the snag falls over, the log becomes a haven for insects and many other animals. The downed log slowly decomposes and returns nutrients to the soil.

However, old-growth forests are not defined solely by trees. Complex, symbiotic relationships develop over centuries between all of the organisms present in the old-growth ecosystem. Lichen in the forest canopy pull nitrogen from the air, which is washed down to the soil and used by the forest's vegetation; symbiotic fungi attached to roots supply plants and trees with water and nutrients and in return take carbohydrates; animals eat tree and plant material and help spread seeds across the forest.

When ancient forests are cut, it takes many years to rebuild all of the severed connections. "When we try to pick out anything by itself, we find it hitched to everything else in the universe," said conservationist and nature writer John Muir. Ancient forests are a magnificent and complex strand in the web of life.

Where you can visit ancient forests:

State Route 20—Happy Creek Forest Walk at mile 134.5. This fully-accessible boardwalk takes you through outstanding western slope, low elevation old-growth forest. For longer hikes, try Thunder Creek and Big Beaver trails.

State Route 542—Horseshoe Bend Trail across from Douglas Fir Campground at milepost 36. One-and-a-half-mile hike on a forested ledge above the North Fork Nooksack River.

Baker Lake Area—The East Bank Trail follows the east shore of Baker Lake and enters the Noisy Creek drainage at upper end. Shadow of the Sentinels is a barrier-free loop trail through old-growth forest (this trail suffered recent storm damage—check with ranger for current conditions).

Published: 29 Apr 2002 | Last Updated: 15 Sep 2010
Details mentioned in this article were accurate at the time of publication


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