Biomass and Chipper Operation Equipment

Biomass and chipper work is where clearing stops being a disposal problem and becomes a production line. The material might be whole trees from a corridor or subdivision, thinnings and residue from a plantation, shelterbelts and orchard pull-outs, green waste at a council or commercial facility, or extracted stumps headed for a grinder, and the output might be boiler fuel, landscape mulch, compost feedstock, animal bedding or export chip. The work is priced per tonne or per cubic metre of product, per hour of chipper time, or as a disposal line inside a clearing contract, and the number that matters is how continuously the chipper or grinder can be fed, because the chipper is usually the most expensive machine on the site and it earns nothing while it waits.

That makes the excavator and its grapple the pacing item. A large chipper fed by an undersized loader is an expensive bottleneck; a shear that drops stems where the grapple cannot reach them adds a handling cycle to every tonne. The attachment fleet that suits this work is the one that fells in bunches, moves bundles rather than sticks, resizes awkward pieces without a ground crew, and keeps contamination out of the infeed.

The work sequence

The chain below is the recovery version of a clearing job. The felling head accumulates stems into bundles placed for the grapple, the grapple keeps the chipper fed, the grapple saw resizes anything too long or too crooked, and stump biomass runs on a separate contaminated stream to a grinder rather than a clean-wood chipper.

1. Position the chipper or grinder and the outfeed
2. Fell and bunch stems toward the landingWL shear with accumulator, or WR15
3. Cross-cut oversize and awkward stemsEX28 or EX36 grapple saw
4. Feed the chipper in bundlesEX28, EX36 or EX40 grapple
5. Extract and split stumps for the grinderWE10 or WE15
6. Shake and clean stump materialgrapple at the laydown
7. Load product to trucks or stockpile

The clearing workflow guide covers how the felling and feeding carriers are kept in balance, which is the whole game in biomass.

Which attachments do the heavy lifting

Forestry grapples for feeding

The grapple decides chipper utilisation, and the specification that matters is capacity in square metres rather than opening, because capacity says how much bundled roundwood or brash the geometry contains per cycle. The Powerhand EX28 forestry grapple (12 to 25 tonne, 0.28 m², 617 kg with rotator, 1,632 mm opening) is the crossover choice for mid-size chippers on a civil excavator, the EX36 (16 to 25 tonne, 0.36 m², 837 kg with rotator, 1,928 mm opening) suits heavy brash and larger log bundles, and the EX40 (20 to 30 tonne, 0.40 m², 1,091 kg with rotator, 2,137 mm opening) is the industrial head for large chippers and grinders. The EX25 (8 to 12 tonne, 0.25 m², 400 kg with rotator) keeps a compact chipper fed from a small carrier. All use inward-angled solid Hardox tines with underside gripping structures that hold a shifting bundle. A rotator is not optional in chipper work: orienting each bundle to the infeed saves seconds every cycle, and at several hundred cycles a day that is hours. Forestry grapple versus sorting grab explains why a demolition grab is the wrong tool for round, springy material.

Grapple saws for resizing at the infeed

Material arrives too long, forked or crooked for the infeed more often than a tidy plan expects, and a grapple saw resizes it in the same cycle instead of calling a chainsaw operator into the exclusion zone. The Powerhand EX28 grapple saw (12 to 25 tonne, 986 kg, 600 mm cut, 900 mm bar, saw motor and chain pitch options) is the versatile choice, and the EX36 grapple saw (16 to 25 tonne, 1,176 kg, 650 mm cut, 1,000 mm bar) handles large timber cross-cutting at a forestry landing. If material is already correctly sized, a plain grapple is lighter and faster, so many operations run a grapple on the feeding carrier and a grapple saw on the felling carrier. The saw capacity is a cutting figure, not a suspended-load figure.

Accumulating tree shears for bunched felling

Biomass felling rewards bunching, because the grapple’s productivity depends on how many stems it lifts per cycle and where they were left. The Trevi Benne WL Series (2.5 to 21 tonne carriers, three models, 50 to 450 mm maximum trunk diameter depending on model) with the optional upper accumulator gathers several small stems before placing the bundle butt-first toward the landing, which is the single biggest lever in regrowth and thinnings biomass. For larger hardwood the WR15 (17 to 22 tonne, around 500 mm nominal cut) and WR20 (23 to 30 tonne, around 550 mm) carry an optional accumulator too, and their rotation options place stems parallel for a full grab. The cut a shear leaves is acceptable for chipping; tree shear versus grapple saw covers when the saw head should fell instead.

Stump cutters for stump biomass

Extracted stumps are a real biomass stream where a grinder outlet exists, and a contaminated one where it does not. The Trevi Benne WE10 (11.5 to 18 tonne, 1,190 kg, 980 mm jaw) and WE15 (20 to 28 tonne, 2,240 kg, 1,400 mm jaw) cut roots, extract and split the stump to a size that stockpiles densely, dries faster and feeds a horizontal grinder without oversize problems. Soil and stone are the commercial issue: a clean-wood chipper dislikes contamination far more than a heavy grinder, so stump material needs a laydown area, a shake and a separate stream. Stump grinder versus stump cutter explains why a Dipperfox, which processes the stump in place, is the wrong tool where the stump is the product.

Carrier size and fleet composition

Biomass operations run two carriers more often than one: a felling machine and a feeding machine, because a chipper waiting for a shear to change over to a grapple is losing money. That is the fleet decision on this page, and it matters more than which class either machine is. The 16 to 25 tonne class is the natural feeding carrier for a mid-size chipper and fells perfectly well with a WR15 when it is the only machine on site. A 10 to 16 tonne machine suits regrowth and thinnings biomass and floats cheaply between sites, a 5 to 10 tonne carrier feeds a compact chipper on council and arborist work, and large chippers and grinders push the feeding carrier into the 25 to 40 tonne class. Check the lift chart and attachment mass guide before choosing a grapple: the larger head is counterproductive if the carrier reaches its lift limit at the infeed radius before the grapple is full.

Site and commercial factors that change the equipment choice

The product specification comes first. Boiler fuel, landscape mulch, compost feedstock and export chip have different tolerances for bark, leaf, soil and particle size, and the tolerance decides whether whole trees go straight in, whether stumps are a separate stream, and whether a chipper or a grinder is the right processor. Dense eucalypt and other hardwoods are heavier per cubic metre and harder on knives and chains, and the safe bundle at the infeed radius is smaller than the grapple suggests; the Australian hardwood guide covers both.

Fire season is a direct constraint: dry chip, dust, hot bearings and a diesel chipper on a paddock of cured grass is the scenario the fire risk guide is written for, and whether the operation runs on a given day is decided by the relevant state fire authority and the landholder’s conditions, not by the schedule. Chipper access, truck turnaround and stockpile space decide the landing layout and therefore the grapple reach. The material still comes from a clearing, so approvals may sit on the source site rather than on the processing; establish before mobilising who holds them and what they permit, with the relevant state agency and the landholder, using native vegetation approvals as the question list. Moisture content and haul distance decide whether the product is worth more than the freight, which is a calculation to make before, not after, the shear is fitted. Operators should establish exclusion zones around the infeed and follow applicable WHS procedures and manufacturer instructions.

Measuring and pricing production

Run a trial on the actual chipper and the actual material and record, per productive hour: grapple cycles and tonnes per cycle at the infeed, chipper idle minutes waiting for material, stems felled per hour and bundles per accumulator cycle, cross-cuts per hour, and stumps extracted and cleaned per hour if that stream is in scope. Tonnes per hour through the chipper against its rated capacity is the utilisation figure the whole rate is built on.

As an illustration only, assume a chipper hired at $300 per hour with a rated 30 tonnes per hour, and a feeding excavator with an EX36 at an internal cost of $220 per hour. If the trial shows the grapple sustaining 20 tonnes per hour, the chipper is at 67 per cent utilisation and the combined cost is $520 for 20 tonnes, or $26 per tonne. If a larger grapple or a better landing layout lifts feed to 28 tonnes per hour, the same $520 buys 28 tonnes at about $18.60 per tonne. That difference is the whole margin on a product sold by the tonne, and it is why the grapple should be sized to the chipper rather than to the excavator. The building a tender rate guide and the cost per unit calculator take the numbers through wear, fuel and utilisation.

Before you tender or buy for this work

• Obtain the product specification (fuel, mulch, compost, chip) and its tolerance for bark, leaf, soil and particle size.
• Confirm the chipper or grinder infeed opening, rated tonnes per hour and the bundle geometry it accepts.
• Record the material: stem diameter distribution, length, species and whether stumps are in scope.
• Check the carrier lift chart at the infeed working radius for the grapple plus rotator plus hitch plus a full bundle.
• Confirm continuous auxiliary flow, pressure and case drain for the saw motor, rotator and any accumulator control.
• Plan the landing: chipper position, truck turnaround, stockpile area and a separate laydown for stump material.
• Confirm the fire-danger stop conditions and the fire equipment required around the chipper.
• Price knives, chains, bars, tines and blades for hardwood, and carry spares to keep the chipper fed.
• Ask whether native vegetation approvals apply to the source site and who holds them.

Frequently asked questions