Since he moved to Olympia, new employee Bryan has experienced two windstorm related power outages. "Why the heck does Olympia have so many power outages, isn't our electricity system any good?" he wondered. I responded that we have too many Doug firs and other shallow rooted species standing around power lines to ever be safe for long:

In order to understand the effect of construction on big tree health, it's necessary to imagine how the root structure looks underground. Many people believe that tree roots descend dozens of feet into the ground, balancing the big top of the tree with a similar underground mass. This doesn't happen. If you've ever seen the roots of a wind-rocked Douglas fir, you've seen the "pancake" like shallow wad they make. Roots are essentially shallow, even on big trees.

 

Most feeder roots that take up nutrients lie within two feet of the surface. They are located near the outer edges of tree root systems and usually extend well beyond a tree's drip line. Large anchoring roots located closer to the trunk typically extend down another two to three feet.

While we're on the subject, some good thoughts from the city of Redmond on windstorms.