If you own a garden with trees, sooner or later you’ll be forced to dig out your tools and do a little pruning.

Reasons to Prune a Tree

Pruning may be required for a number of reasons:

• To remove branches that are diseased or damaged.
• For aesthetic purposes.
• To trim the height of the tree.
• To improve light penetration and air circulation by thinning the tree out.

The Best Time to Prune

Though diseased branches should be removed whenever they occur, pruning to change the shape of a tree or to reduce its height is best done when the tree is in its dormant period – generally, late autumn or winter.

Pruning when the tree is dormant reduces sap loss and minimises the risk of insect or fungus attacks.

The Branch Collar

Look closely at the branch you want to remove. Around it, where it joins the trunk, you’ll see a slight bulge in the bark. This is known as the branch collar. When pruning, all cuts should be made on the branch side of this collar, never into the collar or directly flush with the trunk. Cutting into the branch collar will damage trunk wood and cause unneeded trauma to the tree.

How to Cut

Other than direct cutting, the branch collar can be damaged by tearing branch wood and bark. To avoid this during pruning, follow the cutting steps below.

1. Using a pruning or bow saw, make a cut about 12 cm out from the trunk on the underside of the branch you want to remove. Cut only 1/3 of the way through the branch. The purpose of this cut is not to remove the branch but to prevent a tear in the bark running back to the tree and damaging the branch collar or trunk wood.
2. About 5 cm further out from your first cut, saw right through the branch, starting on its upper side. You’ve now removed the bulk of the branch and any tearing caused by its weight has been contained by your first cut.
3. Now you can trim the remaining branch stub by making a third cut parallel to the trunk and just outside the branch collar. As there is very little weight in the stub there should be no risk of tearing.

Tool Care

Infections and diseases are easily spread to other trees by infected pruning tools. After pruning any tree, disinfect your pruning tools with a weak solution of bleach and water, then rinse and dry before moving on to another tree.

To see a demonstration of tree pruning check out this video.