Hmm, can't say really. It does seem like the big leaf maple likes to case harden or some thing like that as I sand. Seems like cherry does the same thing, but I seldom get cherry here. I am a fan of the LDD method (liquid dishwashing detergent, 1/2 and 1/2 soap to water, use brown or lemon soap, not green or blue as they will dye the wood, 24 hour soak then rinse). It might be the lanolin in the soap that helps lubricate the wood as you sand, not sure, but it does make sanding less of a pain. A long time ago, I learned to sand at slow speed, both drill and lathe, though to sand my warped bowls, I can't sand at anything more than about 10 to 15 rpm. The abrasives just cut better because they have the time to dig in and cut, which they really can't do if you are sanding at high speeds.
Other than that, I don't like punky wood.... or palm....
robo hippy