Several years ago I tried selling apple wood to 2 BBQ joints. First place turned me down because I used regular bar oil. Their regular supplier used something else, non petroleum. Second place I was just about to do the deal(for store credit mind you) and they backed out thinking my wood was cut too long ago and too dry.
yep if wood is too dry like under 18% it dosen't work well for smoking. About 20-25% moisture seems to work well.