Ask a Consulting Arborist Q&A: Root and Soil Concerns

Q: One of the main roots of our Podacarpus is pushing up the walkway. Should it be cut or shaved?

Thursday, December 31, 2015  

Q: I have a Podacarpus (either a Neriifolius or Gracilior) with about a 56" circumference and at least 70 years old. One of the main roots is pushing up the walkway. Should I cut the whole root off or shave it down? Will that damage or cause instability, as the tree is weighted to one side where the root runs?

A: I recommend you try to do what you can to avoid cutting the root. Shaving would be a lower level choice. If you can ramp the walkway over the root, that would be preferable. If that causes a surface drainage problem, tunnel under the root and leave it open or insert a U-shaped drain line with area drain caps on both sides. If this is a concrete walkway, you could stop the walk an inch or two before the root and begin the walk again an inch or two after the root. You could use soil, decomposed granite, or asphalt as a filler between the walkway and root.

Cutting the roots within four or five times the trunk diameter will weaken its support, so that should be a last resort. I don't know how shallow the roots are, or if it is leaning. A number of other important pieces of information are also lacking. It would be best to hire an RCA from our website to examine the situation.

 

Responder: Gregory Applegate, RCA #365, Tustin, CA