Some of the rocks were on the towel fresh from baking, lol.
1 looks suspect to iron deposits but you can't really tell in the pic.
The branch does feel somewhat soft though, almost the way that corkboard would feel if you pushed on it, although the stems are easily snapped. You can see the cracks along the main branch.
Some of the bark remnants looked like birch almost, but upon burning i didn't really think so though, it put itself out quick and this whole piece is dry.