Steep-slope forestry
Steep-slope harvesting can require levelling carriers, traction winches, tethering, winch-assist systems, cable yarders and specialist extraction equipment.
Australian suppliers include systems from TimberMAX, Falcon Forestry and purpose-built forestry OEMs. Falcon Forestry is represented in Australia through Randalls, while Onetrak supports specialist Tigercat and winch-system applications.
The commercial reason for winch assistance is not simply climbing ability. Potential benefits include:
- mechanisation of terrain previously requiring manual work
- improved machine stability
- access to difficult stands
- increased operator protection
- greater utilisation of expensive machines
But the complete system must be engineered. A winch-assist installation is anchor, machine, rope, monitoring, procedures and competency — together, documented, and compliant with the applicable state forest safety code.
Excavator versus purpose-built forestry carrier
This is one of the biggest commercial buying decisions.
Conventional excavator
Advantages: lower acquisition cost, large used market, familiar technicians, easy resale, interchangeable attachments, and the ability to return to civil work.
Disadvantages: forestry guarding may need modification, hydraulic cooling may be inadequate, boom geometry may be suboptimal, operator visibility may be inferior, and a conventional excavator may suffer in continuous forestry duty.
Purpose-built forestry carrier
Advantages: designed for continuous forestry work, better guarding, optimised boom geometry, forestry cab, cooling, integrated controls, specialised undercarriage and forestry telematics.
Disadvantages: high capital cost, narrower secondary market, less useful outside forestry, specialist parts and transport complexity.
Commercial rule for carrier selection
The question should be:
How many paid forestry hours will this machine perform each year?That single number does more to determine the right answer than any specification comparison. High annual forestry hours favour the purpose-built carrier, because the cost of poor duty-cycle capability compounds every shift. Low annual forestry hours favour the versatile excavator, because the fixed cost is spread across several industries rather than one.
The related question — and the one that separates careful buyers from optimistic ones — is how many of those hours are contracted rather than hoped for.
The carrier decides more than the attachment
In attachment-based fleets the attachment gets the attention and the carrier makes the decisions. Operating weight, boom geometry, hydraulic capacity, ground pressure and transport dimensions together determine which attachments can be fitted, what can be held at reach, where the machine can work and how much of the week goes into moving it.
That ordering has a practical consequence: choose the carrier first, then the attachments it will carry. Buying an attachment and then finding a carrier for it is how contractors end up with a machine that can close a shear on material the boom cannot safely lift.
Wheels, tracks and the ground you actually work
Wheeled machines are faster between work points, cheaper to run and easier to transport. They suit firm ground, road and corridor work, and operations where travel is a significant share of the day.
Tracked machines spread weight, hold grade and work soft or broken ground that stops a wheeled machine. They cost transport, travel speed and undercarriage maintenance — which is one of the largest single maintenance costs on a tracked forestry machine and should be in the cost model from the start.
Six-wheel and bogie configurations sit between the two: better flotation and traction than four wheels, better mobility than tracks, at the cost of capital and manoeuvrability.
The choice follows the proportion of your work that is actually difficult, not the worst site you have ever seen. A tracked machine specified for occasional steep ground carries its transport and undercarriage cost on every job, including the flat ones.
Reach, and where the machine is allowed to stand
On corridor, roadside and rail work the reach requirement is set by access rules rather than by vegetation. The permitted standing position may be metres further from the work than the site suggests, and the calculation is: permitted position to the vegetation, plus the required clearance envelope, at a geometry where the lift chart still supports the load.
A carrier specified against the trees alone will be short on exactly the jobs where access is most controlled — which is most established corridors. Establish the standing position with the asset owner before specifying boom configuration.
Sizing to access rather than to capability
The most common carrier mistake in access-constrained work is sizing for the largest job rather than the typical one. A machine that produces more per hour but cannot enter half the sites in your client base earns less per year than a smaller one that fits.
This is most acute in urban arboriculture, where gate widths, driveway crossings, overhead services and surface load limits govern, but it applies to plantation thinning, corridor work and council clearing as well. Size against the access your work actually has; then check that production is adequate, rather than the other way round.
See hydraulics and carrier matching for the compatibility side of this decision, and excavator versus purpose-built forestry carrier for the structural comparison.
Slope, stability and what the numbers mean
Slope capability is one of the most misread specifications in machinery. A published figure describes what a machine can do under defined conditions — usually firm, dry, uniform ground — and a real slope is none of those things.
Four things change the effective limit, and none appear on a specification sheet:
Ground condition. Wet, loose or broken surfaces reduce grip and stability well before the machine's rated limit.
Attachment and load. Mass at reach shifts the centre of gravity, and it does so most at the moment the machine is working. A stability envelope quoted for a bare machine is not the envelope you are operating in.
Direction of travel and slew. Across-slope and downslope behaviour differ from upslope, and slewing a loaded boom across a side slope is where stability is actually tested.
Dynamic loading. Braking, boom movement and sudden release of a load all apply forces the static figure does not contemplate.
Ground pressure is a contract term, not a preference
Ground pressure is machine weight distributed over the contact area, and it determines both what the machine can cross and what it leaves behind.
| Configuration | Relative ground pressure | Suits |
|---|---|---|
| Narrow tyres | Highest | Firm, dry ground; road and corridor work |
| Wide or flotation tyres | Lower | Soft ground where travel speed still matters |
| Bogie tracks over tyres | Lower again | Soft or broken ground; compaction-sensitive stands |
| Full tracks | Lowest for a given mass | Soft, steep or broken ground; sustained duty |
The trade is consistent: everything that lowers ground pressure costs travel speed, transport simplicity, or both. That is why the choice should follow the proportion of your work that is genuinely difficult — a configuration specified for occasional soft ground carries its penalty on every firm-ground job as well.
On stands facing further thinnings or another rotation, this stops being a preference. Compaction affects growth, it is increasingly written into contracts as a threshold, and running gear is the control that determines whether you meet it. The same logic applies on civil and council work, where ground damage becomes a rectification cost, and in wet-weather operations, where the difference between working and standing down is often a running-gear decision made months earlier.
Transport is a specification
Machine dimensions and mass with the attachment fitted determine float requirements, permit needs and how quickly a fleet can move between work fronts. On scattered work, mobilisation can consume more days per year than breakdowns.
Establish four things before committing:
- Transport width, height and mass as configured — with the attachment fitted, not bare.
- Whether the attachment must come off to travel, and how long that takes at each end.
- What permits the configuration requires in the states you actually work in, and what lead time they carry.
- Whether a standard float carries it, or whether a specialised move is needed each time.
A machine that travels as a standard load will complete more billable work per week than a faster machine that needs a specialised move — and the difference compounds across a year of scattered jobs in a way no production comparison captures.
Matching the carrier to the duty
Different work asks different things of a carrier, and the specification that matters changes with it.
| Work | What governs the carrier choice |
|---|---|
| Plantation harvesting | Stability under a head at reach; terrain capability; sustained hydraulics |
| Corridor and roadside | Reach from the permitted standing position; transportability; setup speed |
| Land clearing | Lift chart at reach; hydraulic capacity for the heaviest attachment; cross-industry resale |
| Urban arboriculture | Access dimensions and surface loading; setup time |
| Fuel reduction | Sustained full-load capability and cooling; flotation on rough ground |
| Establishment | Traction and ballast for draft implements; seasonal utilisation elsewhere |
Reading that table shows why "which carrier is best" has no answer. Each row optimises a different thing, and a carrier excellent in one row is frequently mediocre in another — which is the whole reason this chapter sits before the machine-class chapters rather than after them.
Undercarriage is a cost, not a component
On tracked machines the undercarriage is among the largest single maintenance costs over an ownership period, and unlike most costs its remaining life is measurable rather than a matter of judgement.
Three things drive consumption, and all three are within the operator's control: travel (undercarriages wear by moving, so a machine that tracks long distances between work points consumes far more than one that works and stays), ground (abrasive, rocky and wet-abrasive conditions are harder than clean ground), and tension and alignment (running slack or misaligned accelerates wear across every component at once).
Two practical consequences for buying. On a used machine, get the undercarriage measured rather than eyeballed and price the remaining life into the offer — it is one of the few condition questions with an objective answer. And when comparing tracked against wheeled for work involving substantial travel, put undercarriage consumption in the cost model rather than treating it as maintenance noise.
Standardise the interface across the fleet
A detail that only becomes visible on the second or third carrier: coupler and hydraulic interface standards determine whether attachments move between machines or belong to one of them.
A fleet where every carrier takes the same coupler and the same hydraulic connections can redeploy an attachment in minutes when a machine is down or a job changes. A fleet where each carrier has its own arrangement owns the same capability several times over, or accepts that half of it is idle whenever a particular machine is.
The cost of standardising is paid at purchase — sometimes a specified coupler rather than the supplied one, sometimes an adaptor. The cost of not standardising is paid every time the fleet needs to flex, and it compounds as the fleet grows. Worth deciding deliberately at the second carrier rather than discovering at the fourth.