I am planning on replacing the existing driveway next summer. The new driveway that being planned will be wider than the existing one. At one side of the end (street end) of the driveway is a mature black walnut and a mature white pine on the other side. How careful must I be and how close can I be when digging around these two trees without disrupting the root systems?
Minnesota Master Gardeners say:
Generally speaking the circumference of a tree's root system extends at least as far from the tree as does the leaf canopy. Try not to dig any closer to the tree than this distance. Here is a good fact sheet on Protecting Trees from Construction Damage
Note the section on street trees, regarding pavement problems.
