So there you are, hiking along the trail, and suddenly, there's an odd sight: a whole colony of trees with pistol-grip shaped trunks:

A group of trees doing the samba along the trail. They are trying to tell you something.

David Montgomery, our own local genius grant recipient at the University of Washington, where he teaches geomorphology, says such trees are "an invitation to curiosity."

Step back. What is the context?" That, Montgomery notes, is a key clue. If just a tree or two are sinuously bent, perhaps they are searching out the sun through a hole in the tree canopy.

Just one tree with a bent trunk might mean the tree is searching for sun

On the other hand, if you see a whole group of trees in a slow motion slide, perhaps they are trying to tell you something. "A whole group of trees doing the samba, that's different," Montgomery notes.

These trees look like they are slip sliding away

Douglas MacDonald, photos

Trees that look like they've slipped and are trying to catch their balance may be doing exactly that. One possible explanation for what you are seeing, Montgomery said, is a grain-by-grain landslide, with the trees slowly trying to recoup their vertical position as the slope they are growing on s-l-o-w-l-y slides... inexorably... bit... by... bit... downhill.

The instability of a slope can be revealed by trees' efforts to remain upright. It may take awhile, but it's a battle the trees eventually will lose to soil creep.

Learning how to recognize so-called pistol-butt trees is a job skill for people who survey slopes for potential instability. For hikers, its just one more thing to watch for to add interest to the trail.