What to Prune Pruning Young Trees

For most young trees, maintain a single dominant leader growing upward. Do not prune back the tip of this leader. Do not allow secondary branches to outgrow the leader. Sometimes a tree will develop double leaders of the same height known as co-dominant stems. Co-dominant stems can lead to structural weaknesses, so it is best to reduce or remove one of the stems while the tree is young.

Nursery trees often have low branches that may make the tree appear well proportioned when young, but low branches are seldom appropriate for large-growing trees in an urban environment. How a young tree is trained depends on its primary function in the landscape. For example, street trees must be pruned so that they allow clearance for traffic. Most landscape trees require only about 8 feet of clearance.

The height of the lowest permanent branch is determined by the trees intended function and location in the landscape. Trees that are used to screen an unsightly view or provide a windbreak may be allowed to branch low to the ground.

The spacing of branches, both vertically and radially, in the tree is very important. Branches selected as permanent scaffold branches must be well spaced along the trunk. Maintain radial balance with branches growing outward in each direction. Avoid allowing two scaffold branches to arise one above the other on the same side of the tree.

Keep these few simple principles in mind before pruning a tree:

  • Each cut has the potential to change the growth of the tree. Always have a purpose in mind before making a cut.
  • Proper technique is essential. Poor pruning can cause damage that lasts for the life of the tree. Learn where and how to make the cuts before picking up the pruners.
  • Trees do not heal the way people do. When a tree is wounded, it must grow over and compartmentalize the wound. As a result, the wound is contained within the tree forever.
  • Small cuts do less damage to the tree than large cuts. For that reason, proper pruning (training) of young trees is critical. Waiting to prune a tree until it is mature can create the need for large cuts that the tree cannot easily close.