I hate cutting wood in brush piles. Even if the wood isnt under tension, you still have to deal with the hazard of running a saw while standing in brush. I usually just hook the truck up to the end of what ever I want to cut and drag it out of the pile first before trying to cut. You can dissect a big pile in a short time that way, but you also endup with all the litte stuff you dont want to mess with being scattered all over the place.