Carrier size guide

What forestry attachments fit your excavator?

Whether you run a 3, 5, 8, 13, 20 or 30 tonne excavator, find your operating weight below and read what opens up, what sits at the edge of its range and what is out of reach. Published ranges are manufacturer figures for the widest model in a series — the right model inside that range is set by your routine work and your lift chart, not by machine weight alone.

Category	1.5–3 tMicro / mini	3–6 tMini	6–13 tMidi	13–20 tStandard	20–30 tLarge	30–50 tHeavy	Circuit
Tree ShearsPublished 2–50 t	Edge of range — confirm model	Core range	Core range	Core range	Core range	Core range	Double-acting
Stump CuttersPublished 11.5–28 t	Outside published range	Outside published range	Edge of range — confirm model	Core range	Core range	Outside published range	Hammer line + drain
Stump GrindersPublished 1.5–30 t	Core range	Core range	Core range	Core range	Core range	Outside published range	Hammer line + drain
Forestry MulchersPublished 1–30 t	Core range	Core range	Core range	Core range	Core range	Outside published range	Single-acting
Grapple SawsPublished 3–30 t	Outside published range	Core range	Core range	Core range	Core range	Outside published range	Dual circuit
Log and Forestry GrabsPublished 13–25 t typical	Outside published range	Outside published range	Edge of range — confirm model	Core range	Core range	Outside published range	Double-acting + rotation
Mechanical PruningPublished Excavator / telehandler	Edge of range — confirm model	Core range	Core range	Core range	Edge of range — confirm model	Outside published range	Varies by tool
Tillage and Ground PreparationPublished 2–20 t	Edge of range — confirm model	Core range	Core range	Core range	Outside published range	Outside published range	Hammer line / double-acting

Core range
Edge of range — confirm model
Outside published range

The short answer

Machine weight tells you which attachments are structurally appropriate. It does not tell you whether your machine will actually run them. Four numbers decide that: operating weight, auxiliary flow in litres per minute, working pressure in bar, and lift capacity at the radius you actually work at. Find your weight band below, then check the other three before you shortlist anything.

Carrier class by carrier class

What opens up at each size, what sits at the edge of its published range, and the constraint that decides it in practice.

1.5–3 t

Micro and small mini excavators

This is the band where buyers most often get caught. The published ranges suggest a surprising amount is available — stump grinders start at 1.5 tonnes and mulchers from around 1 — but the smallest models in those ranges assume a circuit the machine may not have. Check the machine plate for auxiliary flow before you check any catalogue, and confirm whether a case drain line is fitted, because the grinding and mulching motors that suit this class usually need one.

Typical work at this size: Domestic and light commercial work, tight access, backyard and laneway sites
The real constraint: Auxiliary flow, not weight. Many machines this size leave the factory with a basic breaker circuit and nothing else.

In range (2)

Edge of range (3)

Outside range (3)

3–6 t

Mini excavators

The most versatile band in the range relative to machine size, and the sweet spot for arborists scaling past hand crews. Six of the eight categories open up here, including grapple saws, which start at 3 tonnes. The catch is reach: a 5 tonne machine that comfortably holds a grapple saw against the tracks may be well outside its lift chart with the same load at full extension. Read the lift chart, not the attachment weight.

Typical work at this size: Arborist removals, residential clearing, council parks and reserve maintenance, orchard and vineyard work
The real constraint: Lift capacity at working radius. The machine will carry the attachment; the question is whether it will hold the load at reach.

In range (6)

Edge of range (0)

Outside range (2)

6–13 t

Midi excavators

Every category is at least reachable from this band, and most sit comfortably in it. This is where the decision stops being about the machine and starts being about the work: a 10 tonne excavator will run a mulcher, a shear, a grapple saw or a pruning head, and the right answer is whichever matches the jobs you are quoting. If you are specifying a machine and know forestry work is coming, this is the size to plumb properly from new.

Typical work at this size: Civil site clearing, roadside vegetation management, utility corridor work, larger arborist removals
The real constraint: Circuit configuration. At this size the machine can carry anything in the range, so the limit becomes which circuits are plumbed.

In range (6)

Edge of range (2)

Outside range (0)

13–20 t

Standard excavators

The only band where all eight categories sit in their core range simultaneously. Log and forestry grabs open up here, and they are the highest-utilisation attachment most contractors own because almost every site has material to move. The question at this size is no longer what the machine can run but which two or three attachments earn their keep, and that is a utilisation question rather than a specification one.

Typical work at this size: Production clearing, land development, plantation and harvest support, log decks, large vegetation contracts
The real constraint: Nothing structural. At this size the constraint is commercial — which tools you can keep busy enough to justify.

In range (8)

Edge of range (0)

Outside range (0)

20–30 t

Large excavators

Production work, and the band where oversizing starts to be the risk rather than undersizing. Several categories top out around 30 tonnes: stump grinders, mulchers and grapple saws all reach their published ceiling here, and running one on a machine above its range overloads the attachment structure until something cracks. Pruning heads and tillage tools are mostly out at this size — not because the machine cannot carry them, but because the work does not suit a machine this heavy.

Typical work at this size: Broadacre clearing, forestry operations, major civil and infrastructure corridors, quarry and mine rehabilitation
The real constraint: Attachment structure. At the top of this band you are approaching the upper limit of several published ranges.

In range (6)

Edge of range (1)

Mechanical Pruning

Outside range (1)

Tillage and Ground Preparation

30–50 t

Heavy excavators

A narrow band for forestry attachments. Tree shears are the only category in this guide with a published range reaching 50 tonnes, which reflects how shears are used: high-volume felling in open ground where the machine's reach and stability matter more than finesse. For anything else at this size the practical answer is usually a second, smaller carrier rather than a larger attachment.

Typical work at this size: Large-scale land clearing, mine site rehabilitation, major infrastructure projects
The real constraint: Almost everything is below its published range. Tree shears are the exception, reaching 50 tonnes.

In range (1)

Tree Shears

Edge of range (0)

Outside range (7)

Weight is one of four numbers

A machine inside the published weight band can still be the wrong machine. These are the other three checks, in the order they catch people out.

Auxiliary flow, in litres per minute

Sets how fast the tool actually runs. Read it from the machine plate or the manual for your specific configuration, not the sales brochure, which often quotes the maximum available rather than what is plumbed. Undersupplied tools do not fail dramatically — they just run slowly enough to destroy the economics.

Working pressure, in bar

Flow sets speed; pressure sets the force the tool can develop. A shear starved of pressure will stall in hard timber even when flow is correct, and the operator will assume the attachment is undersized when the circuit is the problem.

Lift capacity at working radius

What the machine can safely hold at the reach it will actually work at, not against the tracks. This is what decides which model inside a published range is correct, and it is the check most often skipped on mini excavators.

Circuit type, and whether it exists

Single-acting hammer line, hammer line plus case drain, double-acting, or a dual circuit. Adding one is a workshop job with a real cost that belongs in your purchase comparison rather than discovered afterwards.

The order matters: flow and pressure failures are the ones buyers discover after the invoice.

Case drain is not optional

Piston motors need drainage back to tank at low pressure. Stump grinders and cutters generally require it. Running one without a case drain builds case pressure and kills the motor seals, often inside a season, and it is rarely covered by warranty.

How to read a published carrier range

Manufacturer ranges are precise about something specific, and buyers routinely read them as something broader.

A published range such as “2 to 50 tonnes” describes the series, not a model. It means the range contains models suitable for machines from 2 tonnes up to 50 tonnes — not that any single unit covers that span. The OMEF BIG INCH tree shear range spans six models to cover that width, and matching the wrong one to your machine produces exactly the problems the range was designed to avoid.

Inside a range, the correct model is set by your routine work rather than your machine’s weight alone. For a shear that means your routine stem diameter and your lift capacity at working radius. For a mulcher it means your material and the width you can afford to push. For a grapple saw it means the diameter you cut most often, not the maximum you will ever cut.

Treat published maximums as best-case figures in favourable material, and derate them for dense, fibrous or buttressed Australian hardwood. A shear rated to 600 mm in European softwood is not a 600 mm shear in ironbark.

Five ways this goes wrong

Every one of these is recoverable before purchase and expensive afterwards.

Buying on weight alone

The machine fits the range, the circuit does not feed the tool, and the attachment runs at half speed for the rest of its life.

Reading the range as a model

A series spanning 2 to 50 tonnes contains six models. Buying “the series” and hoping is how the wrong unit arrives.

Ignoring the lift chart

The attachment is well within the weight band and well outside the lift capacity at the reach the operator actually uses.

Skipping the case drain

Cheap to fit at purchase, expensive when the motor seals fail, and generally not a warranty claim.

Fabricating the bracket

A workshop bracket that does not sit right concentrates load where the designer did not intend, and cracks steel.

Trusting brochure maximums

Published capacities assume favourable material. Australian hardwood is not favourable material.

Before you shortlist anything

Carrier match checklist

Operating weight, from the machine plate
Auxiliary flow in L/min, measured or from the manual
Working pressure in bar
Lift capacity at the radius you actually work at
Which circuits are currently plumbed
Whether a case drain line is fitted
Quick hitch type and standard compliance
Whether a machine-specific bracket exists for your carrier
Your routine working diameter, not your maximum
The material you cut most often

Frequently asked questions

What forestry attachments can a 5 tonne excavator run?

Six of the eight categories are within published range for a 5 tonne machine: stump grinders, forestry mulchers, grapple saws, tree shears, mechanical pruning heads and tillage tools. Log grabs and stump cutters are not — both start well above this weight. The real constraint at 5 tonnes is rarely weight. It is whether the machine has the auxiliary flow and the circuit the tool needs, and whether the lift chart supports the load at the reach you actually work at.

What can a 3 tonne excavator run?

Stump grinders and forestry mulchers sit in their core range, and grapple saws become available from 3 tonnes. Tree shears, pruning heads and tillage tools are at the edge of their published ranges. The practical limit at this size is hydraulic: many 3 tonne machines leave the factory with a basic breaker circuit and no case drain, and several of these categories need one.

Is machine weight the only thing that matters?

No, and treating it that way is the most common reason an attachment purchase disappoints. Weight tells you whether the attachment is structurally appropriate. Auxiliary flow in litres per minute tells you whether it will run at rated speed. Working pressure in bar tells you whether it will develop the force it is rated for. Lift capacity at working radius tells you whether you can hold the load where you actually work. All four have to line up.

What happens if I put an attachment on a machine that is too small?

Three things, in roughly this order. The tool runs slowly because the circuit cannot feed it. The machine becomes unstable at reach, because the attachment weight is a bigger share of the lift chart than the designer assumed. And in the worst case the machine tips, which is a safety event rather than a productivity one. Undersizing is more dangerous than oversizing; oversizing is more expensive.

What happens if the machine is too big for the attachment?

You overload the attachment structure until something cracks. A larger carrier develops more force through the same mounting, and the attachment was engineered for the published range. This is why the top of a published range is a limit rather than a suggestion, and why several categories in this guide stop at 30 tonnes.

Where do I find my machine's auxiliary flow?

The machine plate, or the operator's manual for the specific configuration — not the sales brochure, which often quotes the maximum available rather than what is plumbed to the auxiliary circuit on your machine. If the figure is not available, a hydraulic technician can measure it with a flow meter in under an hour, and it is worth doing before a purchase rather than after.

Can I add a circuit to a machine that does not have one?

Usually yes, and it is a workshop job with a real cost that belongs in your purchase comparison. Adding a second auxiliary circuit with solenoid control is more involved than adding a simple hammer line, and retrofitting a case drain is generally straightforward. Get the quote before you commit to the attachment, not after.

Does a quick hitch change what I can run?

It changes how quickly you can change tools, not what the machine can carry. It does add a safety consideration: quick hitch devices should comply with AS 4772-2008 or an equivalent such as ISO 13031-2016, which requires a safety system ensuring the attachment cannot unintentionally disconnect if the primary retention system fails. With heavy forestry attachments swung at height this is a live risk rather than a paperwork item.

I am between two size bands. Which way should I go?

Toward the larger machine, if the site access allows it. A machine at the bottom of an attachment's published range will do the work but will do it slowly and close to its limits, and it will feel marginal on the hardest jobs rather than the easiest. A machine mid-range does the same work with margin. Access is the only good reason to go the other way, and on tight urban sites it is a very good reason.

Where to go next

Check your machine against every categoryEnter weight, flow and the circuits you have fitted, and see what qualifies.

What attachments actually costOnce you know what fits, work out what it costs to own and run.

Hire, buy or subcontractThe utilisation decision, before you commit capital to anything.

The full buyer's guideCategory selection from the top, if you are still deciding.

GlossaryCase drain, hammer line, dual circuit and the rest, defined plainly.

Send us your specsThree numbers and we will tell you which models suit the machine.