How To Prune Trees | Tree Trimming Tips
Although trees in natural environments typically grow well on their own, others require a higher level of care to maintain their aesthetics and structural integrity.
Sometimes, pruning involves larger-stature trees and an understanding of tree biology, as improper pruning can create lasting damage and even shorten a tree’s life. That is when arborist services like ours come in handy.
However, in some cases, it is an easy process you can undertake yourself to ensure your trees remain healthy and beautiful year-round. Of course, there are a number of variables
involved, including the season and the type of tree you want to prune. But here is a basic guide on how to prune trees.
The benefits of pruning
Pruning and trimming your trees has several advantages, including:
- Preserving or improving the shape of the tree
- Restricting the size of the tree
- Encouraging productive growth
- Removing dead wood
- Reducing the risk of falling branches
- Thinning a canopy and allowing air movement through branches
- Increase light and air penetration to the tree’s crown or the landscape below
- Encouraging new growth
- Maintaining a hedge or screen
- Discouraging upward growth on plants
- Encouraging branching
- Reducing competition by thinning out crowded growth
- Removing suckers from grafted plants or root stocks
- Forming plants into unique shapes, including as topiaries
So when can you cut branches off trees? Because each cut can potentially change a tree’s growth, no branch should be removed without a reason.
Most routine pruning to remove weak, diseased or dead limbs can be done at any time during the year with little effect on the tree. As a general rule, growth and wound closure are maximised if pruning occurs before the spring growth flush (more on that below).
A few tree diseases can be spread when pruning wounds provide access to pathogens, which are disease-causing agents. Susceptible trees should not be pruned during active disease transmission periods.
Specific types of pruning may be necessary to maintain a mature tree in a safe, healthy and attractive condition. They include:
- Cleaning – the removal of dying, diseased, weakly-attached, dead or low-vigour branches from the crown of a tree.
- Thinning – a selective branch removal to improve a tree’s structure and to increase air movement and light penetration through the crown. Correct thinning can help retain a tree’s natural shape, open its foliage and reduce weight on heavy limbs.
- Raising – removes the lower branches from a tree to provide clearance for pedestrians, vehicles and buildings and allow for clear sight lines.
- Reduction – reduces the size of a tree, often for vegetation control clearance. Reducing a tree’s spread or height is best accomplished by pruning back the leaders and branch terminals to secondary branches that are large enough to assume the terminal roles (at least one-third the diameter of the cut stem). Careful and proper reduction helps maintain the form and structural integrity of the tree.
In terms of tree trimming and pruning, the act of “lopping” is said to be one of the most harmful tree pruning practices. It refers to the indiscriminate and haphazard cutting of tree branches to stubs or lateral branches that are not large enough to assume the terminal role. Other names for lopping include ‘topping’, ‘heading’, ‘tipping’ and ‘rounding-over’. It is an outdated practice that was once used to reduce the size of a tree.
However, it is not a viable method of height reduction and doesn’t reduce the future risk of tree failures. In fact, it will most likely increase the risk of a significant tree failure in the long term. It can cause stress to trees as a large percentage of a tree’s leaf-bearing crown is often removed.
Leaves are the food producers of many trees, and removing them can temporarily starve a tree. It can lead to decay, as open pruning wounds are more vulnerable to disease and insect infestations. It can also lead to sunburn of a tree’s leaves and branches, which leaves them exposed to high levels of heat and UV light. The result can be bark splitting, diseases and the death of some branches or even the tree itself.
Alternatives include removing small branches back to their point of origin and pruning a larger limb back to a lateral branch that is large enough to assume the terminal role. If large cuts are involved, a tree may not be able to naturally close over the wounds. In this case, the best solution may be to remove the tree and replace it with a species that is more appropriate for the site.
Choose the right tools
When it comes to tree trimming tips, the tools you need for pruning and trimming depend on the scope and nature of the job required. Firstly, always use clean, sharp tools. You should also select the right-sized tool for the branch or branches you want to prune to avoid damage to the plant, but also the tool. Basic maintenance will also help your tools last longer.
Secateurs should be the best you can afford and typically have two types of blades. Anvil secateurs have one cutting blade that cuts against a fixed blade. Bypass secateurs have two sharp blades that cut with a scissor action, and are generally more expensive.
In terms of handsaws, one with a narrow blade can be manoeuvred into crowded parts of the plant. Hedge clippers are ideal for trimming formal hedges, or you can invest in a pair of electric or battery-powered shears.
Trimming smaller branches
Secateurs are like spring-loaded scissors and typically have a locking system that keeps the blades shut when you’re not using them. Start by cutting off small branches near the base of the tree and then moving up. Secateurs can also be used for pruning smaller, low-hanging branches.
Cutting medium branches
A handsaw or lopping shears can cut any protruding or lower-level branches too big for your secateurs. Cut the branch off close to the tree trunk, but avoid cutting the main trunk. You should also ensure you cut the branch on an angle that protrudes slightly off the trunk.
Accessing hard-to-reach branches
In terms of how to trim a tree that is too tall, a pole pruner can be used for hard-to-reach branches. There are also attachments for pole pruners that are handy for cutting thicker branches. It’s also worth mentioning that larger branches should ideally be “undercut” to stop them snapping off at the trunk, which can lead to tears in the bark and expose the tree to disease.
Basically, it’s a matter of starting under the branch and sawing upwards until you have cut halfway through. Then saw down from the top of the branch about three to five centimetres from the undercut. Keep sawing until the weight of the branch pulls away from the tree.
Choose the right time
There isn’t a single best time for tree pruning, as all trees have different needs and requirements. Many shrubs and trees can be pruned in late winter because they are dormant, and it’s often easier to see what needs to be pruned. Pruning trees in winter also often promotes faster regrowth in spring. However, some trees like maples and magnolias bleed sap heavily if pruned at this time, so if this is an issue, wait until they are fully leafed out in late spring or early summer.
In terms of the best time for tree pruning of spring-flowering trees and shrubs, you should aim to do this right after they finish flowering. Those that bloom during summer and into autumn are best pruned in late winter or early spring as soon as their annual growth begins.
And when to prune trees in Autumn? Autumn pruning should generally be avoided because it may stimulate new growth that could be affected by the winter cold. But if you notice damaged, diseased or dead branches, prune them as soon as you can!
Prioritise your safety
All pruning tools are sharp — they have to be to do their job! As such, they need to be maintained regularly and handled with care. Some tips to follow include:
- Dressing appropriately by wearing long pants, a long-sleeved shirt, gloves, non-slip shoes and safety glasses.
- Pruning when the weather is clear, dry and still.
- Wearing a wide-brimmed hat for sun protection — but make sure it doesn’t obscure your vision.
- Keeping your tools clean and sharp. Warm, soapy water can be used to clean them after each pruning session, and blades can be given a light coating of vegetable oil to stop them from rusting. If you suspect a plant might be diseased, a few drops of tea tree oil can help to sterilise your tools before and after pruning.
- Always carrying pruning tools facing down!
Feed trees after pruning
Soon after pruning, most plants will benefit from an application of bio-stimulants to stimulate feeder root growth combined with the addition of a good quality soil improver. Soil improvers release nutrients slowly, improve the structure and moisture retention of the soil and encourage earthworms and beneficial soil microorganisms. They also create organic, nutrient-rich soil that will improve root growth and produce stronger plants and more fruit and flowers. These are typically suitable for plants of most types year-round.