Birch tree roots can sometimes rise above the surface soil to a degree that they interfere with the lawnmower, become a tripping hazard or mar the appearance of lawn grass. Root pruning is also employed to slow growth or stunt the size of a birch tree. According to the University of Florida, birch trees can tolerate root pruning provided the soil surrounding the cut site is kept very moist for an extended period after the excision.
Plan to root prune your birch tree before May 1 or after the August 1 to avoid the active season of the bronze birch borer, which can be attracted to cut wounds that invite an infestation.
Prune up to 50 percent of the surface roots you want to remove in a single pruning session. Allow a recovery interval of a month to six weeks before pruning the remaining 50 percent.
Drive a spade or axe into the roots to sever them at the desired length. Use your spade as a lever to lift the root off-cut up and out of the soil before discarding it. Repeat this process to remove up to the maximum 50 percent of the surface roots.
Replace any disturbed soil and compact it down around the cut wound sites to ensure good soil-to-root contact.
Water the soil around the pruned roots until drenched immediately after pruning. Maintain very moist soil at the cut sites at all times for a period of at least six weeks to prevent drought stress and keep shock from setting in.