Question
Jim,
We have an above ground pool with a silver leaf maple on one side and a flowering cherry on the other.  We recently see what appears to be roots growing under the pool from the maple tree side.  Both trees are about 6 feet from the pool.  Is there a way to kill the roots that are growing under the pool without damaging the tree and how far out will the roots from the cherry grow?
Thank you,

Answer
Tree roots usually extend out about 1 1/2 times the width of the branches. The roots further away from the trunk will be smaller and less of a problem. As long as you do not cut off more than 30% of the root system the tree will not be effected. You can cut the roots off where they enter the pool. You will need to trench along the pool down about 2 feet to make sure all the roots are cut. A root barrier can then be installed in the trench and this will stop the roots form growing that direction. Here is some information on root barriers. Check with a local tree nursery for this product. http://www.centuryrootbarrier.com/