For most Sydney properties, grinding is the right answer. Removal is the right answer when something is going into that ground that cannot tolerate remaining roots: a pool, a slab, a footing, a retaining wall, or in some cases new drainage.
The wrong question is which one is cheaper. The right question is what is going in that spot afterwards.
What actually happens during stump grinding?
A grinder brings a rotating wheel fitted with carbide teeth across the stump, taking off layers until the remaining wood sits below the surrounding ground level. How far below depends on what you want to do with the space, which is why it is worth saying so before the machine arrives.
As a general guide:
- Turf over the top needs enough depth for topsoil and root establishment
- Garden bed needs more, because plants will be rooting into that space
- Replanting a tree in the same position needs the most, and even then, planting directly into a ground stump position is not ideal
- Paving or a path needs the grindings removed entirely and the hole backfilled with compacted material rather than organic matter
What comes out is a pile of wood grindings mixed with soil. That mixture can be raked back into the hole, which is the usual and cheapest arrangement, or carted away and replaced with clean soil. Grindings backfilled into the hole will settle over the following months as the wood breaks down, so a mound that looks excessive on the day usually settles to level. If you are laying turf immediately, factor that in or specify soil backfill instead.
Grinding is faster than excavation, does not need heavy machinery access to the same degree, and does far less damage to the surrounding lawn and garden. Machines come in a range of sizes, including units narrow enough to fit through a standard side gate, which matters on Sydney blocks where rear access is tight.
What actually happens during stump removal?
Full removal generally means excavating around the stump and levering out the stump and the major structural roots as a unit.
It leaves a substantial hole that needs backfilling and compacting, it requires machine access, and it disturbs a much larger area of ground. On a small inner-city block the disturbance can be more of a problem than the stump was.
There are situations where nothing else will do:
- Building works. Footings, slabs, retaining walls and pool shells cannot be poured over remaining root mass. As the roots decay, the ground above them subsides.
- New drainage or services. Trenching through a dense remaining root plate is slow and often impractical.
- Level changes. Where the ground is being cut down significantly, remaining roots end up at or above the new surface.
- Certain soil-borne pathogens. Where a tree has been removed because of a root disease, leaving infected root material in the ground can carry the problem to what you plant next. This is a judgement call for an arborist, not a default.
Do you need council approval for a stump?
For a stump on its own, generally no. The tree is already gone, and council tree controls apply to living trees and vegetation rather than to the remains of one.
Two caveats matter.
First, if the tree is still standing, removing it requires approval in most of Sydney unless an exemption applies. The stump work is the second half of a job whose first half needs consent. Nobody should be quoting you for stump grinding on a living tree without that conversation.
Second, stump work near a tree you are keeping can trigger an approval requirement in its own right. Several Sydney councils require a permit for works within the tree protection zone of a protected tree, including excavation and changes to soil levels. Hornsby Shire, for example, requires a Tree Permit for construction and earthworks within defined distances of a protected tree, with the distance set by the tree’s trunk diameter. Grinding a stump two metres from a large protected neighbour, and carting away the arisings, is exactly the kind of ground disturbance those provisions exist to control.
If there is a retained tree anywhere near the stump, raise it at the quote.
What happens if you leave the stump?
A stump left in place does not simply sit there.
It decays, and decay attracts things. A rotting stump is a food source for termites and a host for various fungi. Termites in a stump do not automatically mean termites in your house, and a stump is not the only reason termites arrive, but it is an avoidable food source close to a structure.
It regrows. Many species, and eucalypts and privet in particular, will send up suckers from the stump and from the root system. Those shoots are fast, weakly attached and persistent, and cutting them off repeatedly is a job that does not end. Removing or grinding the stump is the usual way to stop it.
It gets in the way. A stump is a mowing obstacle, a trip hazard, and a constraint on anything you want to build, plant or pave.
It subsides. As the stump and roots break down over years, the ground above settles unevenly. That is a nuisance in a lawn and a genuine problem under paving.
None of this is urgent. A stump at the back of a large block causing nobody any trouble can be left. A stump beside the house, in a lawn, or where something is going to be built is worth dealing with.
What happens to the roots that are left behind?
This is the question grinding raises and it deserves a straight answer.
Grinding removes the stump and the upper root flare. It does not remove the wider root system, which stays in the ground and breaks down over a period of years. How long depends on the species, the soil, the moisture and the size of the root plate. A large hardwood root system in dry soil can persist for a long time.
Three practical consequences follow.
Fungal fruiting bodies may appear. Mushrooms and brackets coming up along the line of the old roots are usually decay fungi doing exactly the job you want them doing. They are generally not a sign of a problem with anything else in the garden, though it is worth having them identified if they appear at the base of a living tree nearby rather than over the old stump position.
Ground may settle unevenly. As major roots decay, shallow depressions can form along their lines. On a lawn this is a topdressing job. Under paving or a slab it is a reason to have chosen removal instead.
Digging in that area stays awkward for a while. Planting, trenching and fencing near the old position will hit remaining roots.
None of this is a reason to choose full removal by default. It is a reason to match the method to what the ground is going to be used for.
What if the stump is on or near the boundary?
The same principle applies as for a standing tree: the land the trunk sits on determines who can authorise the work.
Where a stump straddles a boundary, both owners need to agree before anything happens to it, and it is worth having that agreement in writing rather than over the fence. Where the stump is on the neighbour’s side but the roots are causing a problem on yours, arranging for someone to grind it is not a decision you can make unilaterally.
There is also a practical point. Grinding produces flying debris and vibration, and machines need working room. If access has to come across a neighbouring property, or the work will happen within a metre or two of a shared fence, tell the neighbour in advance. Most disputes about stump work are about the mess and the surprise rather than the stump.
How do you prepare for the machine?
A short list, and getting it right saves both time and repair bills.
- Locate services. Water, gas, electrical, irrigation, stormwater and communications lines near the stump all need to be identified before cutting starts. A grinding wheel through a service is an expensive afternoon.
- Clear the area. Pots, furniture, toys, vehicles and anything breakable within throwing distance of the machine should be moved. Grinders throw debris.
- Flag anything you want protected. Retaining walls, paving edges, garden lighting, irrigation heads, pool equipment and any planting you care about.
- Confirm access. Gate widths, step heights, soft ground and slope all determine what machine can get in. A measurement in advance avoids a crew arriving with the wrong gear.
- Decide on depth and backfill before the day. These are the two specifications that determine whether the result suits what you are doing next.
- Check for retained trees nearby. If a protected tree is close enough that the work falls inside its tree protection zone, the approval question needs resolving first.
Grinding, removal or chemical treatment?
Products sold to accelerate stump decay work slowly, are not reliable across species, and still leave you with the physical stump for a long period. They are not a substitute for grinding where you need the ground back.
Herbicide treatment is a different thing again, and its purpose is to stop regrowth rather than to remove the stump. It is applied to the fresh cut surface immediately after felling, and applying it later to a stump that has already sealed over is much less effective. Where a species suckers heavily and the stump is not being ground, treatment at the time of felling is worth discussing.
Burning out a stump is not something to attempt on a suburban block, and in much of Sydney it would be prohibited in any case.
Grinding against removal at a glance
| Stump grinding | Stump removal | |
|---|---|---|
| What comes out | Stump and upper root flare, to below ground level | Stump plus major structural roots |
| Ground disturbance | Contained to the stump position | Large excavation around the stump |
| Machine access needed | Moderate, narrow-access machines exist | Excavator access required |
| Damage to surrounding lawn and garden | Limited | Substantial |
| Hole left behind | Filled with grindings and soil, settles over months | Large void needing imported fill and compaction |
| Suits turf or garden bed afterwards | Yes | Yes, with imported fill |
| Suits a slab, footing, pool or retaining wall | No | Yes |
| Suits new trenching through the position | No | Yes |
| Stops regrowth and suckering | Yes | Yes |
| Typical relative cost | Lower | Higher |
How long does the job take?
Far less time than people expect, which is why stump work is usually quoted as a separate visit or added to the end of a removal.
A single straightforward stump with good access is often an hour or two of machine time. What extends it is the things listed above: buried rock or rubble, a broad buttressed root flare, hardwood, grinding to depth for replanting, and carting grindings away rather than backfilling.
Doing the stump at the same visit as the tree removal is generally the efficient option where access allows, because the crew and often the machinery are already on site and the arisings can be handled in one go. It is worth asking for the stump to be priced both ways, as part of the removal and as a separate return visit, so you can see the difference before deciding.
Where the ground needs to be ready for a trade, a slab pour or a landscaper, build in time for settlement or specify soil backfill, and book accordingly rather than the day before.
What affects the cost?
Cost is driven by the same things that drive tree removal cost: access and complexity, more than size alone.
- Whether a machine can reach the stump at all, and what size of machine will fit, is the first question. Stairs, narrow side gates, steep ground and soft lawn all change the answer.
- Diameter and species. A wide stump takes longer. Hardwood takes longer than softwood. Dense, fibrous species take longer again.
- Root flare and buttressing. Some species spread into broad surface roots that extend well beyond the trunk, and grinding those out is a much bigger job than the trunk diameter suggests.
- Depth required. Grinding to turf depth is quicker than grinding deep enough to plant a tree.
- What is in the ground. Rock, buried rubble, old concrete, irrigation lines and services all slow the work and can damage teeth. Services need locating before anything starts.
- Number of stumps. Several on one visit is more efficient than one.
- Raking the grindings back costs less than carting them off and importing clean soil.
Two things are worth clarifying in writing on any quote: how deep the grinding will go, and whether the grindings stay or go. Those two lines are where most stump grinding disputes come from.
What to do with the space afterwards
If you are replanting, do not plant directly into the ground stump position. The mix of wood and soil holds nitrogen back as it breaks down, and the remaining root plate is in the way. Plant a metre or two clear of the old position and you avoid both problems, which is also better for the new tree.
If you are turfing, allow for settlement or specify soil backfill. If you are paving or building, the grindings need to come out and the hole needs compacted fill rather than organic material.
And if the tree was removed under a council approval, check the conditions. Many Sydney councils require replacement planting as a condition of consent, sometimes specifying species, size and position, so the space you are planning may already be spoken for.
Ask for the depth and the backfill in writing
The practical approach is to decide what the space is for, then specify the work to match. An assessment on site establishes access, machine size, what is likely to be underground and whether any retained tree nearby brings approval requirements into it.
Sydney Tree Company provides stump grinding and removal, tree removal, tree pruning, palm pruning, tree health inspection and evaluation, property care, arborist advice and assistance with council tree preservation paperwork across the Sydney metropolitan area and regional Sydney.
Call 0431 732 265 to arrange a free quote and an on-site assessment.