Just my layman's opinions, but, as far as mulch, I would think that redwood would be at least as good as any other options, probably closer to the top of the list. Of course anything is going to break down over time, faster as the chips get smaller, so, once you prepare the area and place the chips, you are sort of committed to finding more of it in a year or so. Until it breaks down to a certain point, you can often get some more time out of it by fluffing it a bit with a rake. Personally though, I'm not sure that I would do it around fruit trees. Not saying it's bad, again, just a layman's opinion, but fruit trees draw enough insects, etc. as it is, some good of course, but some that can be annoying, and seems that mulch on the ground directly under the droppings and so on could be a pretty good breeding ground.