Tree lopping vs pruning: what the words actually mean

The short answer

Lopping is cutting branches or stems partway along their length, between the natural growth points, leaving stubs. Topping is the same thing done to the top of the tree to cut its height. Pruning, as the Australian Standard defines it, removes branches at defined points with the final cut made cleanly to the branch collar. Lopping and topping are described as an unacceptable practice in material published from AS 4373-2007. Pruning is the work councils and arborists will actually sign off on.

In everyday speech the word “lopping” is used loosely for any tree work, including removal. That is fine in conversation. It is not fine on a quote, because what you write down is what you get.

What lopping means, precisely

A Wollongong City Council fact sheet, published with permission to reprint from Standards Australia and based on AS 4373-2007, puts it this way: lopping and topping is the cutting of branches or stems between branch unions, or at internodes on young trees, and this is an unacceptable practice.

Unpacking that: a branch union is where one branch joins another. Cutting at a union, back to a limb that can take over, is pruning. Cutting between unions leaves a length of branch with no growth point at its end. The tree cannot seal that cut properly, so it responds by throwing out a mass of new shoots below it.

The same fact sheet lists why that matters. Lopping increases the rate of shoot production and elongation. The regrowth is weakly attached and prone to failure or collapse. The stubs decay. The natural habitat of the tree is destroyed. It may reduce the tree's lifespan. It predisposes the tree to fungal infection and insect attack. And it is uneconomic for the owner, because lopped trees generally end up requiring removal.

That last point is the one worth sitting with. The usual reason people lop is to make a tree smaller and safer. Two or three years later the tree is a dense head of long, weakly attached shoots sitting on decaying stubs, which is a harder and more expensive problem than the one they started with.

What proper pruning looks like

AS 4373-2007 Pruning of amenity treesis the Australian Standard for this work. Rather than one generic idea of “a trim”, it sets out named classes of pruning, grouped into two types. The Wollongong fact sheet reproduces them:

Crown maintenance, which keeps the crown roughly as it is:

• Thinning. Selectively removing branches through the crown to reduce density, without changing its size or shape.
• Deadwooding. Removing dead branches. The specification should say the minimum branch diameter being removed, otherwise “deadwooding” means whatever the contractor decides on the day.
• Selective pruning. Removing specific nominated branches, for example the one over the roof.
• Formative pruning. Shaping a young tree so it develops good structure, which is the cheapest tree work you will ever do.
• General pruning also appears in the fact sheet's table of classes.

Crown modification, which changes the crown:

• Reduction pruning. Reducing the size of the crown while retaining its structure and shape. The fact sheet flags this class as restricted to trees with suitable secondary branches, so it cannot be done on every tree.
• Crown lifting. Removing the lowest branches to get clearance over a driveway, path or fence.
• Pollarding. A specific repeated regime, listed as suited only to deciduous trees and only to trees that were formatively pruned for it. It is not a one-off treatment you can apply to a mature gum.
• Remedial or restorative pruning. Listed as carried out only on damaged, declining or diseased trees. This is the class that applies to a tree someone has already lopped.
• Line clearance. Pruning for clearance from powerlines, which in most cases is not your job to arrange. See tree removal near powerlines.

Beyond the classes, a paper presented to the National Street Tree Symposium by arboriculture educator Judy Fakes summarises the standard's key points: when removing a branch the final cut should be a clean cut to the branch collar, or where there is no collar, to a position determined by the branch bark ridge; climbing spikes are not to be used on sections of a tree that is being retained; and lopping and flush-cutting are unacceptable practices.

Climbing spikes are a useful thing to watch for. They put a puncture wound in the trunk at every step. On a tree being removed that does not matter. On a tree that is staying, it is a sign the crew is not working to the standard.

Crown reduction is not topping

This is the distinction most people are really asking about when they search for “pruning vs topping”. Both make a tree shorter. The difference is where the cuts land.

Reduction pruning takes each stem back to a suitable secondary branch, one big enough to take over as the new leader for that limb. The tree keeps a functioning structure at a smaller size. Topping cuts the stems at a chosen height and leaves whatever happens to be there, which is usually nothing, so the tree responds with the mass of weak shoots described above.

Practical test for a quote: if it promises to take a certain number of metres off the height, ask what the cuts go back to. A good answer names the secondary branches or says the tree is not a candidate for reduction. A vague answer about “taking the top out” is describing topping.

So why do so many businesses advertise “tree lopping”?

Because that is what customers search for. “Tree lopping” carries far more search volume in Australia than “arboriculture”, particularly in Queensland and Western Australia, so plenty of perfectly good arborists use the word on their sign to be findable. A business calling itself a tree lopper is not proof that it lops trees.

What tells you something is the conversation. Ask what class of pruning they propose and what the cuts go back to. An arborist working to the standard will answer in the standard's language without being prompted. Someone who says they will just take a few metres off the top, for a price that seems cheap for the size of the tree, is telling you what you are actually buying.

How to specify the job so you get pruning

The Wollongong fact sheet gives homeowners a genuinely useful instruction: a quote for proposed pruning work should nominate the pruning type, meaning crown maintenance or crown modification, and the specific class of pruning to be undertaken.

That turns a vague job into a checkable one. In practice:

1. Write down the outcome you want, not the method. “Clearance over the garage roof” is a brief. “Cut it back” is not.
2. Ask for the class in writing. Selective pruning, crown lifting to a stated height, thinning, deadwooding above a stated branch diameter, reduction pruning to nominated secondary branches.
3. Ask for the standard by name. The quote should say the work will be carried out in accordance with AS 4373-2007.
4. Check qualifications and insurance. The City of Sydney, for example, requires tree works to be carried out by an arborist with a minimum AQF Level 3 in arboriculture. Ask for public liability cover too.
5. Check the approval position before anyone starts. See below.
6. Compare like with like. Two quotes are only comparable once both name the same class of work. Our tree pruning cost guide prices each class so you know what to expect, and the tree removal cost guide covers what a quote should itemise.

Pruning is regulated too, not just removal

A common and expensive assumption is that permits are only for removal, so a heavy prune is a way around the rules. In most Australian councils a protected tree is protected against pruning as well as removal, and lopping a tree you were not allowed to touch can leave you in much the same position as if you had cut it down.

Many councils do allow a limited amount of minor pruning without approval. A common local convention is around 10 percent of the canopy in a year. Treat that as a council practice rather than a national rule, because it is not set by AS 4373 and it differs between councils. Judy Fakes makes the same point in the symposium paper: many Sydney councils allow a 10 percent prune on request, and that allowance is not a component of AS 4373.

Before you book anything, check whether your tree is protected. Start with is my tree protected and run your address through the permit checker. If the tree is your neighbour's and the branches come over the fence, your right to cut is limited to the boundary and the same standard applies to the cuts you make: see neighbour's tree overhanging my property.

If your tree has already been lopped

The damage is done, but the outcome is not fixed. Restorative pruning over several visits can thin the crowded regrowth so a smaller number of shoots develop into properly attached branches, rather than leaving dozens competing on decaying stubs. Start it early, while the shoots are small.

Have a qualified arborist assess it rather than guessing. Two things they are weighing up: how much decay has entered at the stub cuts, and whether the regrowth can be managed at all. Some heavily lopped trees are past the point where restoration is realistic, and removal becomes the safer option. If the tree has reached that stage, removing a dead or dangerous tree covers what councils expect as evidence, and an arborist report is usually how you prove it.

Quick reference

• Lopping: cuts between branch unions, leaving stubs. Described as an unacceptable practice.
• Topping: lopping applied to the top of the tree to reduce height.
• Pruning: final cut clean to the branch collar, or to the branch bark ridge where there is no collar.
• Trimming: not a term in the standard. Ask which class is meant.
• The standard: AS 4373-2007 Pruning of amenity trees.
• On the quote: nominate the pruning type and the specific class.
• Approval: a protected tree is usually protected against pruning too. Check your council first.