Milk is the bunny's name. She put in the subtitle of the thread: "madrone wood branches for chewing?" It's not visible when you just click on the thread title from the main page.
Madrone is a hardwood, like oak, so it won't contain aromatic oils like softwoods (pine, fir). I couldn't find anything else on the internet about it's safety for eating except that it's safe to make bird perches out of (and presumably for birds to eat): http://www.mdvaden.com/bird_page.shtml