Extraction — Forwarders and Skidders

Forwarders

A forwarder carries logs completely off the ground in a load bunk. This distinguishes it from a skidder, and it is the reason cut-to-length systems produce cleaner wood with less soil disturbance.

Forwarder economics

Forwarder productivity can be approximated as:

Forwarder Production =
Payload per trip
×
Trips per productive hour

Trips per hour depend on:

• extraction distance
• loading speed
• travel speed loaded
• travel speed empty
• unloading speed
• terrain
• traffic
• log size
• bunk utilisation

A large payload is useful only when the machine can fill it efficiently. If the constraint is loading cycles rather than capacity, a larger bunk adds mass, cost and ground pressure without adding tonnes per hour.

Komatsu 895

The Komatsu 895 is a 20-tonne-capacity forwarder. Current published specifications include:

• 20,000 kg payload
• approximately 21.85-24.83 tonne machine weight depending on configuration
• 210 kW engine
• 1,280 Nm torque
• 262 kN tractive force
• up to 409 L/min hydraulic flow
• crane options up to 205 kNm lifting torque
• 7.5 / 8.5 / 10 m reaches

Komatsu positions the machine particularly strongly for final felling and plantation forestry.

Tigercat 1075C

Another heavy forwarder benchmark:

• 20-tonne payload class
• approximately 27.5 tonnes machine weight
• approximately 230 kW peak engine power depending on emissions configuration
• 8.5 m standard crane reach
• optional cranes with up to approximately 195 kNm gross lift torque

John Deere 2010H and 2510H

The latest large H-Series includes:

2010H — 20-tonne load capacity, 220 kW maximum power, 255 kN tractive force.

2510H — 25-tonne load capacity, 252 kW maximum power, 290 kN tractive force, up to 8.5 m² load-space options.

John Deere specifically notes a 7.5 m² load-space option for heavy hardwood and eucalyptus applications — a reminder that load space, not load mass, is frequently the binding constraint.

Ponsse forwarders

Current Ponsse capacity classes include approximately:

Ponsse positions the 25-tonne Mammoth particularly for long transport distances, plantations and high-volume work.

In August 2026 Ponsse also announced new thinning-focused Scorpion and Wisent Thin Line machines, including a 10-tonne Wisent configuration designed specifically around thinning.

Commercial implication

There is no universal ideal forwarder size.

A 25-tonne forwarder can be commercially excellent where:

• stems are large
• roadside distance is long
• terrain supports the machine
• loading is efficient

A smaller machine may make more money where:

• thinning corridors are narrow
• soils are soft
• individual logs are small
• extraction distance is short
• residual crop damage is critical

Damage to the residual crop in thinning is a real cost. It simply does not appear until the next rotation, which is precisely why it is so often left out of the machine comparison.

Skidders

A skidder drags stems or logs to a landing. They remain highly relevant to tree-length and full-tree harvesting.

Main types

• four-wheel grapple skidder
• six-wheel skidder
• cable skidder
• swing-boom skidder
• clambunk-type extraction systems

Tigercat 635H

The six-wheel Tigercat 635H represents the high-production end:

• approximately 212 kW
• approximately 25.1 tonnes operating weight
• grapple options up to approximately 2.32 m²
• 3.835 m maximum grapple opening
• 23 km/h top speed
• approximately 710 mm ground clearance

Tigercat positions it for high-volume and longer-distance extraction.

When a large skidder pays

A bigger skidder is commercially attractive when:

Large bunches
+
reasonable skid trails
+
high feller-buncher output
+
sufficient landing capacity
+
sufficient processor capacity

are all present.

If the landing cannot process the additional wood, bigger skidding capacity may simply create a larger pile. That is the bottleneck principle expressed in extraction: capacity that cannot be converted downstream is not capacity, it is inventory.

Extraction is where chains become unbalanced

Extraction has a property that felling does not: its cycle time scales with distance. A feller buncher produces at roughly the same rate whether the landing is 200 metres away or 600; a skidder or forwarder does not. That asymmetry is why chains drift toward felling-heavy over time, and why the balanced ratio that worked on one coupe fails on the next.

The practical discipline is to size extraction against the longest haul in the coupe rather than the average. A fleet balanced on the average will be extraction-limited for the portion of the coupe that is furthest out — which is usually the portion that takes longest to work.

Choosing the extraction method

Forwarders carry the load clear of the ground, which suits cut-to-length, protects the soil, and handles sorted products. They are slower to load than a skidder and the loading is where their cycle time goes, so they favour shorter hauls with dense volume and multiple assortments.

Skidders drag stems, which is faster to pick up and harder on the ground and the residual stand. They suit full-tree systems and longer snigs, and their productivity is more sensitive to terrain than a forwarder's.

Cable and winch-assisted systems exist where ground-based extraction is unsafe or would cause unacceptable damage. They are slower and more capital-intensive, and they are the answer where the alternative is not extracting at all.

The choice mostly follows the production system rather than being made independently: cut-to-length implies forwarding, full-tree implies skidding. Where both are genuinely open, the deciding factors are haul distance, soil sensitivity and whether products need to stay sorted.

Ground damage is a cost with a delay

Compaction and residual-stand damage do not appear in the current job's accounts. They appear in the next rotation's growth, and increasingly in the contract as a specified threshold audited after the operation.

Three controls matter, and all of them are decisions made before the machine arrives:

• Running gear — tyre width, bogie tracks and ground pressure specified against what the estate requires rather than what is convenient
• Brash mats — working over residue where the material allows, which is a planning decision about where slash is left
• Track discipline — repeated passes on the same ground cause most of the compaction, so route planning matters more than machine weight alone

Where a stand will be thinned again or clearfelled later, this is not a finish question. It is a cost transferred to the estate, and contracts increasingly return it.

Planning beats capacity

Extraction distance is partly a planning decision rather than a fixed condition. Landing placement, snig track layout and the sequence in which a coupe is worked all change the hauls the fleet actually faces — frequently by more than an additional machine would.

Before adding extraction capacity, establish whether the constraint can be moved by repositioning landings, opening an additional access point, or resequencing the coupe so the longest hauls are worked when truck supply is best. A bottleneck moved by planning is moved at no capital cost, and it moves back the next time conditions change.

See forwarder versus skidder for the direct comparison, and use the bottleneck analyser to establish whether extraction is actually your constraint.

Cycle time, worked

Extraction productivity is a cycle-time problem, and writing the cycle out makes the sensitivity obvious.

A forwarder cycle has four components:

Travel out (empty)
+ Loading
+ Travel in (loaded)
+ Unloading
= One cycle

Loading and unloading are roughly fixed for a given machine, crane and assortment mix. Travel is not — it scales with distance. So as haul length grows, the fixed part of the cycle becomes a smaller share and productivity falls.

Consider a forwarder whose loading and unloading together take 30 minutes per load, travelling at an average 5 km/h loaded and unloaded over the extraction route:

The figures are illustrative — substitute your own loading times and travel speeds — but the shape holds everywhere: quadrupling the haul does not quarter production, but it removes a substantial share of it, and it does so without any change in the machine.

That is why landing placement is worth arguing about before the first stem is felled: it is the cheapest way to shorten the haul the fleet actually faces.

Loading and the crane

On a forwarder, loading is where the non-travel cycle time goes, which makes the crane a more consequential specification than it first appears.

Reach determines how much can be gathered from one position, and therefore how often the machine repositions. More reach means fewer moves and less lifting capability at that reach — the trade is real and should be made against the geometry of your sites, not against the catalogue.

Assortment count matters more than it seems. A coupe producing four sorted products requires more selective loading than one producing a single assortment, and that shows up in loading time rather than in any published figure.

Grapple size should match the material. A grapple larger than the logs being handled gathers no faster and adds weight at reach.

Ground conditions change the machine, not just the rate

Wet or soft ground does more than slow extraction. It changes which machine is viable, and it introduces a cost that appears in a later rotation rather than in this job.

Three controls, all decided before the machine arrives:

Running gear. Tyre width, bogie tracks and flotation specified against what the estate requires rather than what is convenient. This is increasingly a contract condition rather than a preference.

Brash mats. Working over residue where the material allows spreads load and protects soil. Whether that is possible is decided by where slash is left during felling — which makes it a harvesting decision, not an extraction one.

Route discipline. Repeated passes on the same ground cause most compaction. Planning routes, and accepting a slightly longer one to spread traffic, is the cheapest soil protection available.

Where the stand faces further thinnings or another rotation, none of this is a finish question. Compaction affects growth, and contracts increasingly return that cost to the contractor.

Landing design is extraction capacity

A landing is not a clearing; it is a piece of infrastructure that sets the pace of everything delivered through it, and it is cheap to get right before the first stem arrives and expensive afterwards.

Four things it has to accommodate at once: a processor or loader working without repositioning constantly, sorted product stacks with room to grow between truck arrivals, truck access and turning without reversing long distances, and somewhere for residue to go.

Undersize any of those and the constraint moves to the landing regardless of what the machines can do. A landing too small to hold stock between trucks stops extraction as soon as haulage falls behind; one without sorting space forces re-handling that consumes loader time; one where trucks cannot turn adds minutes to every cycle, all day, for the life of the coupe.

It is worth walking the planned landing with the person who will run the processor before it is built. They will identify the constraint faster than a plan will.