splitting madrone firewood we discovered this delightful critter and larvae. I think the larvae belongs to the beetle just because of the markings, but who knows? the bug is about an inch long. we are hesitant about keeping it around for firewood this winter in case the larvae hatch and infest every other tree around. suggestions?
The insect invading your madrone firewood is the Western ash borer (Neoclytus conjunctus). The larvae riddle the sapwood of freshly cut, bark-covered, unseasoned madrone wood. This insect will only feed on dead, downed madrone, so you don't need to worry about it attacking and killing your trees that are alive and standing. You will likely see the adult beetle emerge from the firewood when it is inside your home. Don't be alarmed, as they are not harmful to humans or homes. This can happen for two or more successive years. As for your concern about keeping the firewood around through the winter - there is the possibility that the insect can spread to other downed, unseasoned, madrone logs or firewood. It will not spread to other species in your firewood pile though.
For more information on insects and diseases that affect pacific madrone, please read Diseases and Insects of Pacific Madrone:
Stay warm this winter - you're fortunate to have a supply of madrone firewood!