Tree Lopping: Understanding Its Impact on Trees

Lopping involves the indiscriminate removal of large branches, typically aimed at rapidly decreasing a tree’s height without consideration for the cut's placement. Topping mirrors this approach, targeting the tree's leader and removing the top to lower its stature. While both methods yield immediate results and appear decisive, the repercussions often manifest later.

Unlike skin, a tree does not heal wounds in the same way. Instead, it isolates the damaged area, forming new tissue around the injury while the harmed wood remains trapped inside. A precise cut made in the correct location results in a manageable recovery for the tree. In contrast, a blunt cut through a substantial limb creates a daunting task for the tree, often leading to failure. Decay fungi and wood-boring insects infiltrate through the exposed wound, allowing rot to progress unseen within the limb.

Then there is the issue of regrowth. When a tree loses a significant portion of its canopy suddenly, it activates dormant buds beneath the bark, producing an abundance of epicormic shoots characterized by rapid, bushy, upright growth. While this may appear as a recovery, it is more accurately a panic response. These shoots are only superficially attached to the old wood, grow quickly, become heavy, and are situated directly above an area of decay. This combination elevates the risk of limb drop years later during a substantial storm. lopping can result in a tree that is more hazardous than the original, with the initial issue likely to reappear within a few seasons.

How Crowning Can Endanger Your Tree’s Health

Crowning is a vague term that lacks a clear definition, as it can refer to various actions such as removing the top of a tree, elevating lower branches, or drastically cutting back the entire canopy. Two individuals may agree to have a tree crowned, but envision entirely different tasks, leading to potential misunderstandings and poor outcomes.

When executed poorly, crowning is not merely an aesthetic issue; it can be lethal for the tree. Three detrimental effects occur simultaneously. First, substantial cuts leave wounds that are too large for the tree to heal, allowing decay to enter through each one. Second, the canopy serves as the tree's food source, and removing a significant portion of leaf area at once severely limits its ability to photosynthesize and repair itself. the regrowth that emerges is weakly affixed to deteriorating wood, producing a structure that is inferior to the original. A healthy, vigorous tree might endure these stresses, but one already burdened by drought conditions may not survive. the term “could” is more accurate than “will.”

The crown operations outlined in AS 4373-2007 specify three types: crown lifting, reduction pruning, and crown thinning, each with distinct meanings:

• Crown lifting: This involves removing lower branches to create clearance beneath the tree, accommodating footpaths, driveways, vehicles, or rooflines. The upper part of the tree remains untouched.
• Reduction pruning: This entails shortening outer branches back to a sufficiently sized lateral branch, thereby maintaining the tree’s natural shape while reducing its size. This method effectively addresses a tree that has outgrown its location, presenting an alternative to hard cutting.
• Crown thinning: This is a process discussed in detail below, often confused with reduction pruning.

When someone offers to crown your tree, the crucial question is to clarify which of these three methods they intend to use and whether the cuts will finish at a lateral branch or in an arbitrary location.

Understanding Crown Thinning and Its Importance for Newcastle Trees

Crown thinning is often misunderstood, yet it distinctly differs from the previously mentioned methods. This technique involves the selective removal of specific smaller secondary branches throughout the canopy to reduce overall density. Importantly, it does not alter the tree’s height or outline. A correctly thinned tree retains the same size and shape it had that morning, simply with less foliage.

The main objective of thinning is to enhance wind and light penetration. A dense canopy acts like a sail during storms, which is particularly significant along the coast. By opening up the canopy, air can flow through the tree rather than being forced against it, alleviating stress on the limbs and root plate. increased light exposure benefits any growth beneath the tree, while improved airflow can mitigate certain fungal issues.

Thinning becomes problematic when it is overdone. Excessive removal leads to a condition known as lion tailing, where bare inner branches are left with only a tuft of foliage at their ends. This shifts the weight to the tips of the branches, counterproductive to the intended outcome. Thinning should involve a light touch applied evenly, rather than a complete clearance of the centre.

Defining Tree Pruning and Proper Cut Techniques

Pruning encompasses a broad category of techniques, and what distinguishes pruning from simply cutting is that every branch is removed for a specific purpose, with each cut made in a designated location.

These cuts should occur at the branch collar, which is the slightly swollen ring of tissue where a branch connects to the trunk or a larger limb. The collar contains the essential tissue that enables the tree to wall off and seal the wound. Cuts made just outside the collar allow the tree to efficiently heal. Conversely, cutting flush to the trunk removes the collar itself, leaving the tree without the necessary tissue to seal the wound, resulting in prolonged exposure. Leaving a long stub also presents issues as there is no living tissue at the cut end to promote closure, resulting in dieback and allowing decay to enter. the same branch and tree can yield vastly different results based on the precise location of the cut.

Recognised types of tree pruning serve specific purposes:

• Deadwooding: Involves the removal of dead, dying, or broken branches. This is the least risky work on any tree and often the most beneficial since dead limbs are prone to falling.
• Formative pruning: Involves shaping a young tree early to encourage the development of a single strong central leader, rather than competing stems that may fail as the tree matures. Investing ten minutes now can prevent the need for removal later.
• Structural pruning: Applies the same concept to semi-mature trees, correcting weak forks and crossing limbs before they become problematic.
• Selective pruning: Involves the removal of individual branches for specific reasons, such as reducing weight over a roof or ensuring clearance from a structure.
• Remedial or restorative pruning: Aims to rehabilitate a tree that has suffered damage, including those previously cut poorly. Trees displaying a cluster of weak regrowth can often be revitalised over time through the selective thinning of regrowth, allowing well-placed shoots to develop into robust limbs.

Understanding Why Newcastle Trees React Poorly to Lopping

The tree canopy in Newcastle predominantly consists of species that do not respond well to blunt cutting, each failing in unique ways.

Spotted gums and eucalypts are prevalent in Newcastle’s yards and streets, already stressed by hot summers, dry spells, and coastal storms. Subjecting these trees to severe injury on top of existing chronic stress leads to eucalypts that can unexpectedly shed limbs. A case study involving a lightning-struck spotted gum in Adamstown Heights illustrates the need for careful assessment rather than a hasty reduction in size.

Brush box is common in older suburbs, capable of reaching heights of over twenty metres in a suburban backyard, making the temptation to remove the top strong. this results in multiple weakly attached regrowth leaders vying for dominance above a decay column stemming from the old cut. Angophoras, or Sydney red gums, found around Merewether, The Junction, and Bar Beach, are structurally complex trees with naturally irregular forms. Major interventions require a thorough understanding of their load-bearing characteristics. Camphor laurel stands out as an exception; aggressive cutting can enhance its vigour, making hard pruning counterproductive.

For a more comprehensive understanding of local species that frequently cause issues, we have detailed the six trees that Newcastle arborists most commonly remove.

Contrasting Lopping, Crowning, Thinning, and Pruning

Choosing Between a Lopper and an Arborist for Your Tree Care Needs

For general garden maintenance, someone equipped with a chainsaw, a trailer, and a solid work ethic is often adequate. Tasks like trimming an overgrown shrub, tidying a hedge, or clearing green waste post-storm do not necessarily require arboricultural qualifications. Many individuals perform this work competently at fair prices.

The situation changes when two critical factors are involved. The first is the health of the tree, particularly if you want it to thrive and remain stable for years to come. The second is the proximity of structures, such as fences, sheds, garages, or houses. This is where a qualified arborist adds value, as the focus shifts from simple cutting to controlling the fall of several hundred kilograms of timber.

Before you book a service, there are three practical points to consider that are often overlooked:

• The title does not guarantee qualifications: Anyone can label their vehicle with a term, so the title itself is not informative. The recognised arboriculture qualification on the national training register is AHC30820 Certificate III in Arboriculture, which encompasses climbing, elevated work platform operations, and tree dismantling. This is a question you can ask directly for clarity.
• Always verify insurance: Public liability coverage is not assured solely by the name on the vehicle. When a tree is positioned over a building, the potential consequences of mishaps are significant. Request proof before work commences, not afterwards. Waratah is fully insured, and our team consists of qualified arborists, so it is reasonable to ask this of any contractor quoting for your tree work.
• Clarify stump removal policies: The individual taking down the tree may not have a stump grinder, and if they don’t, you could be left with a stump in your yard, necessitating the arrangement of a second service to complete what you assumed was a single task. It is wise to clarify this in the quote. Stump grinding is included in Waratah’s services, ensuring the job is completed in one visit.

Essential Questions to Ask Before Tree Pruning or Removal

If you remember nothing else, keep these three questions in mind.

• What arboricultural qualifications do you possess?: A satisfactory response will specify an actual qualification, such as AHC30820 Certificate III in Arboriculture, and the person should not react defensively to the inquiry. A solid answer also includes the type of pruning being quoted: crown lifting, reduction pruning, crown thinning, or deadwooding. If the response is vague, such as “tidying up” or “taking a bit off the top,” it is telling.
• Can I see proof of public liability insurance prior to work commencing?: The document to request is a certificate of currency, and the appropriate time to ask is before anyone climbs the tree. A business with coverage will readily provide this documentation.
• Will you grind the stump, or will it remain?: A clear yes or no response upfront informs you if you are booking one job or two.

If the tree in question belongs to a neighbour or its branches extend over a fence, ensure that you determine who has the authority to authorise the work before proceeding. Our guide on neighbour tree disputes in NSW provides further information. check with your local council regarding any protections that may apply to the tree, as these protections are in effect regardless of the work being performed.

When Is Tree Removal the Better Option Over Pruning?

Pruning is not always the ideal solution, and ignoring this fact is unhelpful. Occasionally, a tree may be too compromised, too damaged, or simply in an unsuitable location. A qualified arborist should provide you with a straightforward assessment of your situation. Signs indicating that tree removal may be more appropriate than pruning include significant portions of the canopy being dead or diseased, notable internal decay or hollowing of the trunk, an increasing lean, and root damage affecting stability. Storm damage warrants its own evaluation, and trees that are dangerous or storm-damaged must be assessed before any action is taken.

Ultimately, the correct approach hinges on the individual tree: its species, condition, and proximity to nearby structures. That is the purpose of an onsite assessment, during which a professional evaluates the tree and determines which of these four terms accurately applies.

Common Queries Regarding Lopping, Crowning, Thinning, and Pruning

What distinguishes tree lopping from tree pruning?

Lopping refers to the indiscriminate cutting back of large branches to swiftly reduce a tree's size, often disregarding where the cuts land. Pruning, on the other hand, involves the careful removal of specific branches for defined reasons, with each cut made just outside the branch collar to facilitate healing. Although the same saw may be used, the outcomes for the tree differ significantly.

Is tree lopping detrimental to trees?

In most cases, yes. Large blunt cuts create wounds that the tree struggles to seal adequately, allowing decay fungi and wood-boring insects to invade and spread rot within the limb. The tree responds by producing numerous epicormic shoots that are weakly attached, grow rapidly, and become heavy. As a result, a tree subjected to this treatment can become more prone to limb drop during storms rather than less.

Can crowning lead to a tree's demise?

It is possible, but it depends on the tree and the severity of the cuts. Removing a significant portion of the canopy at once eliminates the leaf area the tree relies on for sustenance. The large cuts left behind are usually too extensive for the tree to heal, allowing decay to set in, while the subsequent regrowth is weakly attached to decaying wood. A robust, healthy tree might recover, while one already stressed by drought or poor soil may not.

What does it mean to crown a tree?

Crowning lacks a defined pruning type, which contributes to the confusion surrounding the term. It can refer to removing the top of the tree, raising lower branches, or drastically cutting back the entire canopy. The established crown operations include crown lifting, reduction pruning, and crown thinning, making it important to clarify which method is being discussed.

What is crown thinning, and when is it necessary?

Crown thinning involves the even removal of a portion of smaller secondary branches throughout the canopy, reducing density without altering the tree's height or shape. This technique alleviates wind load, which is crucial along the coast, while also increasing light and air circulation through the canopy. If excessive thinning occurs, it can lead to bare inner branches with foliage only at the tips, ultimately worsening the tree's condition rather than improving it.

Do I require an arborist, or is a lopper suitable?

For general garden maintenance, hedge trimming, or clearing green waste, an individual with a chainsaw and trailer is typically adequate. a qualified arborist is essential when the health of the tree is a concern or when nearby structures, such as fences, sheds, garages, or houses, are present. This is where effective control over falling timber and proof of insurance become critical.

Is there a standard in Australia for tree pruning?

Yes, AS 4373-2007, Pruning of Amenity Trees, was published in March 2007 and remains current. It encompasses the removal of deadwood, crown lifting, formative pruning, reduction pruning, selective pruning, crown thinning, and remedial or restorative pruning. Notably, lopping and topping are not included in the practices covered.

Can a tree recover after being lopped?

Recovery is often possible, but it typically takes years rather than weeks. The restorative approach involves gradually thinning out weak regrowth over multiple visits, allowing a few well-placed shoots to develop into strong limbs and monitoring decay in older wounds. Some trees may be too far gone for recovery, which is a judgement made on-site.

Steven Brown is a qualified arborist and co-owner of Waratah Professional Tree Care, a family-run business providing tree services across Newcastle and the Hunter region since 1998. For a pruning assessment or to receive a free quote, please call (02) 4956 6602 or reach out online.