Apple trees need to be pruned throughout their lives. The most important period for pruning and training is the first 4 to 5 years. Properly pruned and trained young trees will produce high quality apples.
First year pruning of apple tree:
At planting, the un-branched one-year-whip should be cut off 30 inch above the ground. Lower heading results in a few vigorous shoots developing bellow the heading cut. Higher heading results in the development of shorter shoots.
Sometimes, branches are not at the right location. The desired height of branches on new trees is 24 to 40 inches above the ground. Branches that are higher or lower should be removed. If all branches are too low or too high, all branches should be removed and the trees should be treated as non-branched-whip.
After the first growing season, the tree has a new terminal shoot (1-year-old section), several-1-year-old-limbs and the original whip (2-year-old trunk section). The central leader (1-year-old section) should be headed to a bud on the windward side by removing 1/4 to 1/3 of the past seasons growth.
Sometimes trees may produce few shoots in the first season. If less than three shoots developed, the shoots should be removed because they will become dominant. If all shoots develop on one side of the tree, they should all be removed to maintain a balanced tree.
Second year Pruning of apple tree:
The central leader will develop vigorous terminal shoots bellow the heading cut. Excess shoots should be removed early in the season when they are 4 to 8 inches long. It will promote the growth of most desired shoots.
After two-year, the tree has a one-year-old leader, a two-year-old trunk section with one year old limbs, the original whip with 2-years-old branches. Do not head all branches with wide crotches should be removed and central leader should be header by 1/4 to 1/3.
Three years old apple tree pruning:
Always prune to just above an outward facing bud.
Four year old apple tree pruning:
Trees should be treated as in the third season. Remove vigorous waterspouts and strip and spread competing shoots on the central leader and scaffold limbs. If these waterspouts are growing vertically, they can be re-oriented to less than 45° from vertical to retard vegetative growth and induce fruiting. These waterspouts will become fruiting systems and can be removed after fruiting for 2 or 3 years.
Beyond the Fourth year trees:
Apple trees that are older than 4 years are treated as matured trees. Read about matured apple tree pruning here.