Hi Mike..

The brittleness and color of the wood you are describing leads me to concur...sounds like redwood.

I would try cleaning the surfaces to be joined with acetone. If that does not work you may want to try one of the urethane based glues. They are a bit pricy, but may do the trick. A word of caution regarding urethane glues: this material will forceably expand as part of the curing process. You must clamp the joint in such a way as to restrict the expansion. This expansion will actually force apart a joint that is not adequately clamped. I prefer to use an alphatic resin type glue.

Best of Luck, Keep us informed,

Charley Dean, Carson City, Nv