How and when to prune trees

CandideZA
Published on August 5th 2020
9
As the longest living species on earth, trees are vital. They provide us with a link between the past, present, and future, and it is our responsibility to respect them and to protect them for the future.
Pruning a tree plays a very important role in the future of a tree and it is therefore important to know how to do it in order to ensure for a long and happy life for that tree.

What is your objective?

One for the most important things to consider before you want to prune a tree is an objective. Do you need to shape your tree, clean your tree from dead or dying branches, raise the shape of your tree, perhaps find a central leader, or are you in a situation where you need to maintain clearance between the tree and nearby objects?
Another thing to take into consideration before pruning is whether you have a young or mature tree and whether this tree is deciduous or evergreen. Usually, the goal for a younger tree is to prune in order to create one dominant trunk/central leader and to establish the permanent, lower branches. Mature trees, on the other hand, are mostly pruned to manage the growth of the tree or to correct and repair damage caused by ageing, storms or pests and diseases. One will thus focus on enhancing the appearance of a mature tree whilst reducing the risk of damage.

When to prune?

Timing comes into play when we start talking about deciduous and evergreen trees. A general rule of thumb for deciduous trees (trees that lose their leaves in winter) is that they are to be pruned in autumn or winter. However, in some cases, like with Magnolias, pruning should be done in late summer. Evergreen trees on the other hand, seldom need pruning. Mid to late summer is a good time to prune if you would like to remove damaged or diseased branches.
Further to the timing of pruning, we circle back to the objective. Why you prune will to some extent determine when you will prune. For instance, removing dead and diseased branches and a bit of light pruning can be done almost anytime. Below is a brief discussion about pruning within a seasonal aspect.
Winter
This is the most common time to prune when trees are dormant and one can see and observe the shape of the tree. Come spring, trees will burst with new growth.
Spring
Trees blooming in spring should be pruned right after their flowers fade. Summer flowering shrubs and trees should be pruned during winter or early spring.
Summer
When pruning in summer, it is usually done to either direct growth or to remove defective limbs which can be seen more easily. Prune right after the seasonal growth is complete.
Autumn
Do not prune in autumn! Spores of decay fungi tend to spread around this time and wounds tend to heal slower.

How to prune

Pruning a tree depends on a number of unique things; the kind of tree, its manner of growth and natural habit, how much space it requires, area in which it is planted, soil conditions, wind and so the list can go on. It is therefore important to take your unique situation and tree into account when stepping back and deciding what needs to be done to produce a balanced, attractive tree.
This task must be tackled with great care as the wrong cuts could spoil the basic shape and intrinsic beauty of a tree forever. Below is a list with a few pointers before you start:
  • Each cut has the potential to change the tree forever...
  • Large limb removal can impact form and geometry which will impact stability.
  • Always start by removing the 3 D’s: dead, diseased and damaged wood.
  • When pruning a young tree, maintain a single dominant leader growing upward. Do not prune the tip of the leader or allow secondary branches to outgrow this leader.
  • Make the correct cuts above healthy buds or side shoots.
  • When pruning large branches, first cut off the bulk of the branch before making the final cut flush with the trunk.
  • Do not top your tree!
  • Prune out problems like weakly attached branches in decline, crossing and rubbing branches or overextended weak and large branches.

A few common tree issues

V-shape junctures
It is very common for some trees to naturally form narrow, V-shape junctures. Some require corrective pruning. Very narrow junctures will be weak and the tree will be at risk in a storm with strong winds. If your tree is purchased young, remove one of the stems to ensure for a strong structure in the long run.
Suckering
Suckers are a tree’s attempt to grow more branches which are often in response to some kind of injury. Normally suckers won’t be a significant problem, but at some point, they should be dealt with whether for aesthetic reasons or the long term health of the tree. Save the straightest stem and remove all others with clean and sharp pruning shears.
Forked trunks
These trunks tend to grow together and are less stable than a single trunk. The expected outcome will be a split in the tree. To prevent this, remove one of the forked trunks while the tree is still young as close to ground level as possible.
Clustered branches
Too many branches bunched together can cause problems and also look unattractive. Thinning out these branches will result in more sun, air and water supply for the remaining branches.
Trees are very important assets to our survival and provide functional and aesthetic benefits. It is important to plan the maintenance and pruning program of your trees in such a manner that it benefits your trees whilst minimizing the inputs required for the trees to survive. In the end, it will be better for the tree, the owner and the environment.
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