WIJDW,
  Hmmmm.  Between you and aray63, that's really interesting.  I'm thinking that especially for hilly areas, this would be a real benefit.  I've never heard of it, but keeping those huge roots in place to loosen the soil really is intriguing.  I am tickled about the historical angle.  Thanks for a neat point.  Stetts 
Edited to correct aray63's name....