Tree Pruning – A Detailed Note
Tree Pruning
Tree pruning is the removal of unwanted branches from a tree either for reducing risk and inconvenience to the public, maintaining or improving tree health and structure, or improving the appearance of trees.
Improper tree pruning is detrimental to the appearance and healthy growth of trees and may result in irrecoverable damage to trees.
General Guidelines on Tree Pruning
These general guidelines provide basic information on tree pruning and issues requiring particular attention during execution of works.
Tree pruning should be carried out by trained personnel and under proper supervision by experienced personnel with expertise in horticulture, arboriculture and tree care.
Objectives/Purposes of Tree Pruning
The objectives of pruning should be established prior to the commencement of any pruning operation. The purposes of tree pruning are broadly grouped under the following three categories –
- (a) Reducing Risk and Inconvenience to the Public
- (i) keeping the roads clear and safe by removing the branches which obscure sightline of motorists or physically obstruct the vehicular accesses, leaving insufficient headroom for large vehicles or double-decker buses.
- (ii) preventing interlacement with overhead cables by regular pruning of trees to maintain acceptable clearance from overhead cables.
- (iii) protecting pedestrians and properties from damage by the dead, hanging and detached twigs/branches falling from the tree. Twigs/branches with potential to fall should be removed once detected.
- (iv) maintaining road lighting condition by removing the branches of trees blocking street lamps.
- (b) Maintaining or Improving Health and Structure of Trees
- To maintain trees in healthy growing conditions by
- (i) controlling the invasion of pests and diseases by removing dead or insect-carrying twigs and branches in order to eliminate the harbourage for pests and diseases.
- (ii) avoiding wastage of food reserve by removing weak branches and undesirable shoots originating from the tree base to save food reserve for healthy parts of the tree.
- (iii) allowing more light and air in or through the crown by removing overcrowded leaves, twigs and branches.
- (iv) minimizing the chance of damage under strong wind by reducing the weight of the tree by pruning out overcrowded twigs and branches. This is essential particularly when the root anchorage of the tree is not firm when the root system is disturbed by transplantation or adjacent construction work.
- (c) Improving the Appearance of Trees
- To maintain trees in their most desirable form and structure.
Types of Pruning
The types of pruning are broadly grouped under the five categories listed below –
Formative Pruning
Selective pruning of the lateral branches of a tree so as to develop a strong and straight trunk, a well-balanced crown with properly spaced scaffolding branches and a clear central leader.
Crown Lifting
Selective pruning to remove lower branches to increase vertical clearance from ground level.
Crown Reduction
Selective pruning to reduce the overall height and spread of the crown, leaving the tree in a well-balanced and natural form and shape.
Crown Thinning
Selective pruning to remove weak, thin, crossing and live branches to reduce the density of foliage. Crown thinning should not affect the overall height and spread of the tree.
Cleaning
Selective pruning to remove dead, withered, damaged or diseased branches.
Timing of Pruning
The best timing for pruning each species may vary and expert advice should be sought when necessary. In general, the following criteria apply
Evergreen Tree
Pruning of evergreen trees just before spring is preferred due to faster healing in the coming growing season.
Deciduous Tree
Pruning of deciduous trees after shedding leaves in winter when trees are dormant is preferred. This can minimize the risk of pest problem associated with wounding and allowing trees to take advantage of the full growing season to close and compartmentalize wounds.
Young Tree
Suitable structural pruning of young trees would facilitate the development of a straight trunk.
Pruning for improvement on health of trees or reducing risk and inconvenience to the public may be conducted as and when required.
Safety Measures for Tree Pruning
The following safety measures are recommended for pruning operations to protect the operatives and public:
- Avoid pruning trees on humid, windy and rainy days as far as possible.
- Deploy adequate manpower to maintain traffic flow.
- Clear and fence off the tree pruning area to prevent entry by others.
- Place directional/warning signs to divert traffic/pedestrian, with approval from the authority, if necessary.
- Operatives to put on proper protective clothing such as goggles, chainsaw trousers, safety boots, gloves and helmets.
- Use appropriate tools for the job such as small chainsaws, pole saws, tubular saws, long pruners, ladders and ropes.
- Remove objects attached to the trees which may hinder the pruning operation.
- Bring along a first-aid kit for an emergency.
Pruning Techniques
Pruning should be performed by trained personnel and under proper supervision by experienced personnel with expertise in horticulture, arboriculture and tree care to ensure that it is done safely and properly.
Some common pruning techniques are listed below for reference.
- Dead branches must be cut back to live tissue/growing point.
- Single top cut resulting bark tearing should be avoided and instead undercut technique should apply.
- Where removal of a whole lateral branch is required, do not cut flush to the main trunk or leaving a stub. The final cut shall be made close to the trunk or parent limb, without cutting into the branch bark ridge or collar. Long and heavy branches should be cut in the sequence of the section by section.
- Avoid topping (i.e. cutting the trunk and branches between nodes leaving stubs) on mature trees. Topping would damage the tree form and structure as well as initiate decay in trunk and branches.
Points To Note
Some general good practices are listed below for reference
- Over pruning would affect the healthy growth of trees. A good practice is to limit the removal of the crown to not more than one-quarter of the original coverage in each pruning operation. Also, the crown should be kept in a well-balanced and natural form and shape after pruning.
- Pruning prior to flowering seasons of trees should be avoided.
- Clean and sharp tools should be used to produce smooth and clean cuts to facilitate healing and reduce the risks of attack by insects and fungi.
Courtesy ETWB
SEE ALSO: Tending Operations | Weeding | Cleaning | Climber Control | Pruning
Tree Pruning – FAQ
The best time to prune or trim trees and shrubs is during the late winter while they’re dormant. Pruning during the dormant season is ideal because: The wounds heal faster, keeping the plant strong.
Trimming is essentially applied to shrubs and hedges, pruning is meant for tress and shrubs. Both services are performed at different times using different equipments.
Pruning fruit trees is a necessary chore that improves sunlight penetration and increases air movement through the tree. Pruning also develops the structure of the tree so that it can support the crop load. Damaged limbs are susceptible to disease and insect infestations that could further damage the tree so such branches are pruned.
When pruned properly, removed tree branches will not grow back. Instead, the tree will grow what looks like a callous over the pruning cut, which helps protect the tree from decay and infection. Because trees heal all on their own, you don’t have to use a pruning sealer!
The stems should be cut at about a 45-degree angle. Cutting the stems at this angle, rather than straight across, allows for greater surface area and a corresponding increased water uptake.
Injuring a plant by pruning doesn’t have to hurt the plant’s overall health. In fact, pruning stimulates a plant’s natural healing process, which promotes healthy growth. Flowering plants usually produce more flowers after pruning. Likewise, fruit trees often produce larger and healthier fruit after pruning.
Trimming the top damages or removes the apical meristem which activates the axillary meristems to grow. This stimulates the plant to produce more rhizomes which results in more branches.
Crowning is the removal of a portion of smaller/tertiary branches, usually at the outer crown, to produce a uniform density of foliage around an evenly spaced branch structure. It is usually confined to broad-leaved species. Crown thinning does not alter the overall size or shape of the tree.
You should always prune with sharp, clean tools to prevent injury, ragged cuts, and disease. Take care to clean your trimmers, saws, and pruning shears between uses, thoroughly drying them and storing them in a clean, dry place. If pruning is done properly, there is nothing to put on pruning cuts then.
The objective is clean and shartp cuts. For this purpose, choose bypass pruners, which cut like a pair of scissors, with a curved cutting blade that slides past a lower broad blade. Also called lopping shears, a lopper is the tool of choice for cutting branches 2 inches in diameter. The lopper label should specify the branch size it will cut.
When should trees be Pruned?
What is the difference between Pruning and Trimming?
Why is Tree Pruning important?
Do tree branches grow back after Pruning?
Why do plants are cut at an angle?
Does Pruning hurt plants?
Why trimming the top of a plant make the plant bushier?
What does Crowning a tree mean?
What to put on pruning cuts?
If you want to, first remove all jagged edges where the tree limb was cut also remove dust debris from the limb stub. Dip a paintbrush in the container of liquid pruning sealer, and use the paintbrush to coat the limb stub with the sealer. Allow the sealer to dry for one hour, and then check the stub to ensure it is completely covered with the sealer.
The research from the University of Arizona says that you should not use pruning sealers after pruning your trees or shrubs. In fact, it found that pruning sealers actually obstruct trees’ natural healing power. Plus, pruning sealers may trap moisture in the tree, which can encourage wood decay or fungi. What is the best tool to cut tree branches?
Good sir
Thanks 🙂