While they can do some damage, a winter moth infestation on a large, well established tree is unlikely to kill it. Maples especially have an ability to refoliate rather easily when affected by a lot of insect predation or other cause for loss of leaf. But it IS stressful to the trees and repeated severe infestations and resultng defoliation can weaken the trees, affect growth and cause branch die back.

There is no known control for the adult moths but you could spray during the dormant season with a horticultural oil that will smother the eggs before they hatch. Or spray at bud break in spring with Bt to kill the caterpillars. If the trees are too large for you to treat yourself, you might need to hire an arborist with the necessary equipment to reach all the nooks and crannies of a big tree. It is also advised to keep affected trees well watered during the growing season to encourage new leaf development.