I'm pretty sure oak is okay, but I would stay away from anything that has a strong aroma. Someone else will have to chime in that knows better than me though. Maple, apple, and aspen are all good, basically it's just the pine and cedar that are the worst ones. Now, are you talking about making another half-log that's open on both ends, or a box with 4 sides? Because really, unless you're dead set on making another half-log hide, I would recommend just going to the dollar store and getting a couple of dark opaque plastic bowls and cutting holes in the sides. They're much more secure for a bp, unless you're putting one end of the half-log up against the back of the enclosure. Just my suggestion though... if the half-log has worked fine for you up to this point, then that's cool and it's up to you