Trees keep our air supply fresh by absorbing carbon dioxide and producing oxygen.
Trees cut down noise pollution by acting as sound barriers.
Tree roots stabilize the soil and prevent erosion.
Trees improve water quality by slowing and filtering rain water as well as protecting aquifers and watersheds.
Proper pruning techniques are crucial to extending the life of any tree. Incorrect cuts do not allow a tree to heal and may invite unwanted pests due to easier access into its interior. It is important to keep the branch collar intact when pruning to allow the wound to seal. However, you do not want a branch to remain out beyond the collar since the bark cannot close over and seal it to prevent disease.
Pruning landscape trees is done for a number of reasons. The most common reasons are to improve the health of a tree, removal of hazardous limbs or branches, and guiding tree form and structure.
When the Prune?
As a general rule trees should be pruned in the winter or early spring before the buds begin to show. During this time the tree reserves are high and the tree is dormant which makes it less at risk for disease and insects.
How to Prune?
- When removing a branch, always cut outside the branch bark ridge and collar. Do not make a flush cut.
- Branches that do not have a distinct collar should be cut at a right angle to the branch outside the branch bark ridge.
- Trees may have co-dominant stems. If a co-dominant stem must be removed, cut at an angle outside of the bark ridge. Avoid leaving any stub. For most species, the tree should have a single trunk.
- When removing heavy limbs, first make an undercut several inches outside of the collar. Then remove limb by a second cut an inch or so outside of the first cut. Remove stub with a third cut just outside of the collar.
- Avoid pruning off more than 25% of a tree’s leaf area in any one year.
- Always avoid topping trees as this causes the tree to form unnaturally and weakens the tree.
- Where possible, try to encourage side branches that form angles that are ⅓ off vertical (10:00 or 2:00 positions).
- For most deciduous (broadleaf) trees, don't prune up from the bottom any more than ⅓ of the tree's total height.