Question
I want to encirce a large maple tree with either a stone masonry wall or an ep henry type product.  The tree is approixmatly 20 inch in diameter.  How big a diameter might I need to avoid cutting large roots or having roots disturb the wall later on?

Answer
A 20" tree needs a 20' radius or a 40' diameter to protect its critical root zone. The structural root plate is about the first 10' from the trunk and this is even more critical to be protected. I rarely would recommend encircling an existing tree with masonry that requires digging any kind of footing. If you care about the tree you will come up with an alternate that involves stacked stone with no footing or mortar and can move or flex with the root growth.
Good luck
Sean J Murphy, LA,ISA, LEED AP
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