Burning in piles is how I cleaned up my small orchard 3 years ago. I didn't want to wade through brush piles when using my herbicide sprayer to kill the weeds afterward. Planting seedlings was much easier too. Also, its easy for a casual walk when you don't have to wade brush. I left some patches of fine branches, not piled, just scattered, they'll break down quite quick anyway. I used some of the wood for furnace wood, but most the apple wood and cherry was in poor shape so it kept the brush piles burning. Omce I got that apple wood on the fire I could burn limbs green with some extra handling of the burn piles. Because a fire just burns in the centre and doesn't travel much if there is no wind, even then it only burns to one side. 2 years afterwards it looks like someone took a sac of wild flowers and broadcast over the site, talk about plant diversity, although most of the colors are blues, yellows and whites. They don't seem to interfere with my planted yellow birch seedlings as they were 12 + inches high when planted from Jiffy containers. I'm just glad its not barn yard grass or cooch.