Dear Laura, I contacted you previously about the big poplar that is in between and very close to two condos here where I live. It's huge, I believe it to be at least 30 years old and so probably full grown. I'm on the condo board so it has fallen to me to try to make a determination about whether the roots will destroy the foundation of either condo or both. By the way, I have contacted two arborists through the treesaregood.org website (thank you for that), and am awaiting their calls. The roots on this tree are largely exposed and we are contemplating adding more dirt there and grading properly for better drainage. The question of the hour is, can a tree's roots be cut vertically say 10-12 feet from the tree (and close to the structures) without harming the tree? We would like to try to keep this big shade tree, cotton and all, but are quite worried about damage to foundations nearby. What will stop a tree's roots from growing into a foundation, short of cutting it down? Thanks again for your help. Jan Bridgman
Oakland County Michigan
The arborist will be able to determine how much root can be pruned, and where.
Here are articles discussing root barriers, which sounds like what you need. (Please excuse if I already gave these to you)
The second link demonstrates a technique used in the south, and I don’t know if it is useful here- check with the arborist.
One guide from the International Society of Arboriculture indicates a mature tree can tolerate root pruning 1.25 feet out, per 1 inch diameter of trunk at ‘chest height.’ For example, a tree with a 20 inch diameter trunk, measured about 4 1/2 feet up, could tolerate root pruning ( 1.25 x 20) =25 feet away from the trunk. Partial root pruning- say on just one side, is different and so needs an arborist evaluation.
I hope the tree can be preserved, but if it can’t we’d be happy to help you select replacement trees for that location. Regards, Laura