When to prune trees?

 

 

When to prune trees?

 

You cannot prune trees all year round. The two best times of the year to prune trees are summer and winter.

It is best not to prune trees in spring or autumn. Because during the spring the leaves are still emerging and during the autumn the trees have to shed their leaves. At both times the tree has insufficient energy reserves to properly seal its pruning wounds.

And if you do prune, you needlessly weaken the tree.

When you prune a tree also depends on the type of pruning you are going to apply.

For example, the pruning time for pollarding is the winter period, because you will then activate more dormant eyes and adventitious buds.

Lighting or taking in a tree is best done in the summer when the tree has its maximum energy level.

You must also take the tree species into account when pruning. Read more about this in the article ABC trees.

You are also allowed to go alone trees in good condition pruning. Prune weak or weakened trees, these with loss of condition, can be fatal for the trees.

 

 

 

When is pruning least harmful to the tree?

 

It is best to prune a tree in the summer. From June to the end of September. That is the least harmful period for the tree.

When a tree is fully in leaf and the leaves are fully developed, you can prune the tree.

Because then the tree's energy level is back to a high level and there is still an entire growing season to seal off pruning wounds. The tree can then best defend itself against parasitic fungal infections and others attacks and attackers.

 

 

When do trees have their highest energy levels?

 

Trees reach their maximum energy level in the summer period, when the leaves have fully emerged and are fully mature.

When we prune, we want trees to be at their maximum energy level. Because then trees can heal their pruning wounds best.

By healing we mean sealing off the remaining wood from the outside air and overgrowing pruning wounds with callus. This makes trees appear better diseases and infestations.

From the moment the leaves appear on the trees in spring, the trees start to build up their energy level.

The leaves act as small solar panels that release CO₂ convert into sugars. This is because of the chlorophyll that is present in the leaf. And through the photosynthesis and the presence of UV light, sugars are formed.

These sugars are energy building blocks for creating wood cells, and therefore also callus or wound overgrowth tissue.

Pruning trees in the summer is therefore better because the tree has much more energy than in the winter. Also because the tree can heal its wounds for an entire growing season.

 

 

The leaf development (leaf development) and leaf fall determine the pruning time

 

The moment of leaf formation and leaf fall help determine when we may or may not prune.

The end of the tree's leaf development determines the first pruning time. When leaf development is complete and the leaves are fully grown, the first pruning work can begin. The trees have already had a few weeks to replenish their energy reserves through their leaves.

On the other hand, the moment when the leaves start to change color and subsequent leaf fall determines the last pruning time.

When the first leaf discolouration occurs in autumn, you should no longer prune a tree.

The tree then needs all its energy to create cork lines between the twig and the leaf stem and must heal all these small wounds when the leaf has fallen.

The starting time and end time when you can prune a tree is different every year. And depending on the weather conditions.

During a warmer spring, the trees will leaf out faster and you can prune more quickly. And when it stays warm longer in the autumn, the leaves will stay on the trees longer.

 

 

During leaf development and leaf fall, the tree uses a lot of energy from its reserves

 

A tree's energy reserves consist of sugars that it has stored in its sapwood, trunk, roots, branches and twigs.

This during the growth period, namely from late spring, summer and early autumn, when there are leaves on the tree.

The tree will use much of this energy at the start of the growing season to make new leaves and wood. The tree will also use a lot of this stored energy to heal the leaf scars in the fall when the leaves fall.

If, during the periods of leaf emergence and leaf fall, you prune the tree, which means removing twigs and branches, a double drain is placed on the tree's energy reserves.

On the one hand, energy reserves are pruned away and on the other hand, the tree must start sealing off wounds at a time when the tree is already busy with either leaf development or leaf shedding.

By pruning trees during leaf development or leaf fall, you needlessly weaken the tree and the tree will more easily fall prey to attacks and attackers.

Note that trees with a poor condition and reduced vitality can cause death.

 

 

When to prune ABC trees?

 

We always prune ABC trees in the summer period. Never at the end of winter or early spring.

ABC trees are trees that can bleed when pruned. And bleeding can be fatal for these tree species.

In winter and spring, the root pressure of the upwardly pressed water on ABC trees is much greater and more intensive than on other tree species. Who do not belong to this group.

When pruning ABC trees in winter or spring, pruning wounds will bleed.

The moisture from the living wood then flows out of the pruning wounds. As a result, the tree loses not only moisture, which is necessary to maintain its life processes, but also sugars. His energy.

The fluid that drains from the pruning wound often flows down the branch or trunk under gravity. This means that branches or trunk always remain moist for a long period of time.

This moisture then contains a bacterium that attacks the bark of the tree and can eventually cause rot.

Moisture loss from the pruning wound, energy loss, infections and even rot are all things you want to avoid when pruning trees.

To prevent bleeding from the pruning wounds, ABC trees should be pruned in the summer.

In the summer, when the tree is fully in leaf, the root pressure of the supplied water is much smaller and there is a lot of evaporation of water through the leaves. Bleeding is then not an issue.

The trees can then neatly seal off their pruning wounds and overgrow.

 

 

Which trees are ABC trees?

 

The group of ABC trees includes:

• Acer (maple),
• Betula (birch),
• Carpinus (hornbeam),
• Juglans (walnut),
• Fagus sylvatica (beech), only sporadically in specific cases,
• Gleditsia triacanthos (honey locust),
• Laburnum anagyroides (laburnum),
• Aesculus hyppocastanum (white horse chestnut),
• Populus (poplar) and Pterocarya (wingnut).

 

 

 

A tree can bleed to death

 

If you do not respect the pruning time for an ABC tree, the tree can bleed to death. You may still need the tree afterwards cut.

It is better that you take this into account when you prune trees.

Below you will see a video of a walnut (Juglans regia) from which a branch was pruned (during the felling of the tree because it had completely rotted at the base of the trunk and was unsafe). And where bleeding occurred.

The video of this walnut was taken during the felling the tree. The tree had to be felled urgently because the tree was badly affected by a parasitic fungus and the tree was in danger of falling over.

And because the tree had to be felled anyway, it was an ideal educational moment to film the bleeding.

 

 

 

 

The type of pruning determines when we prune trees

 

When you prune a tree also depends on the desired result and the type of pruning you apply.

Pollarding and pruning fruit trees is best done in winter.

Do so outside the frost period to prevent damage to the cambium (this is the growth layer between the bark and the sapwood). Damage to the cambium makes callus formation more difficult.

Pruning during winter activates more dormant buds or adventitious buds. This is an advantage when knotting. More twigs are formed and the knots overgrow with new tissue more quickly. In other words, callus formation occurs faster.

Below is another photo of the care of a pruning wound to promote callus formation (wound overgrowth).

 

 

 

 

It is better not to prune trees in poor condition. It weakens them even more.

 

We have already explained a few things about when to prune a tree. And there is one more important condition.

Only a tree in good condition, so without loss of condition you can prune.

As already explained above, pruning takes away the energy reserves that are present in the branches and twigs. A tree with a poor condition or a weakened tree, desperately needs all these energy reserves for system recovery and defense.

If you now take away energy reserves, the tree will no longer be able to properly defend itself against intruders and attackers. This weakens the tree even more. And the chance increases that it will be fatal to the tree.

It is therefore not wise to prune the dead ends of dying branches for the aesthetic appearance. It is much wiser to identify the cause why the tree is in poor condition. And probably one is location improvement the solution. Always ask about this advice.

Let you to advise by arborist en certified tree manager Bert Janssens to determine whether your tree may be pruned.

We would like to mention that on our web page 'pruning a beech tree' explain more about the physiology of trees and their energy. And how all this affects the condition of a tree.

Be sure to ask us advice when you wish to have a tree in poor or weak condition pruned.

 

 

 

Misunderstandings about when it is best to prune a tree

 

Unfortunately, there are many misunderstandings surrounding when we prune trees and the correct time of pruning.

In the past, trees were often pruned in winter. Because there was more time during the winter. And there was no work to be done in the fields.

Or trees were pruned in the autumn, when the nuts had fallen. Or when the fruit had ripened. Nuts and fruit are important food to get through the winter. Earlier pruning means loss of yield and loss of food in this case.

In spring and summer, on the other hand, there was no time. There had to be planning on the one hand and harvesting on the other.

 

 

 

Please feel free to contact us with any questions about when it is best to prune your tree

 

If you have any questions, don't hesitate to contact me contact and feel free to ask your question.

We are happy to explain to you on site at your home and in detail why it is often better to prune a tree in the summer.