Interlocking Wood Grain-What is it?

Hi Everyone,

I've received a question about interlocking wood grain-what exactly is that?

Normally the grain of a tree runs up and down the long axis of a tree. Interlocking grain is the result of a spiraling of the wood grain up the long axis of a tree. Periodically, every several years, the grain will switch back on its self and spiral in the opposite direction. This makes for a very strong tree but it's really hard to machine this type of wood as the surface tends to tear up rather easily.

Here is a link to a pdf article on the subject. It's a good discussion on the subject and also of basic tree anatomy:

http://www.treeworld.info/f29/spiral-interlocking-grain-trees-17891.html

Be sure and scroll down a little. You'll see a link to the article.

VW