Notch fruit trees in the late winter to early spring, while the trees are still in the dormant period. It can be done as late as two to three weeks before bloom. Use a ladder if you're targeting parts of the tree that are unreachable from the ground.
Insert a knife or hacksaw into the bark just above a bud or node until you hid hardwood. Wiggle the blade in a half-circle shape under the bark until it is loosened. Remove a piece of the bark. The cut releases the bud from the dormant period and a branch will grow.
Put the knife blade into the bark just below a bud or node to encourage fruiting. Once you hit hardwood, move the blade in a circle and strip away the piece of bark. This will result in a fruiting spur or fruiting bud next season.