We planted a few cottonless cottonwood trees 21 years ago in our suburban yard and they have grown a lot. We've since cut down one that got too big for its area. Another is a beautiful backyard tree that loses limbs occasionally. We know that cottonwoods continue to get large and can drop large limbs sporadically. Is there a publication or other advice for homeowners to manage residential cottonwoods? Should we get it trimmed professionally so it won't drop limbs on our neighbor's house or get too large? thank you!