SB Forestry Ltd hosted a working thinnings harvesting demonstration in a mixed stand of larch and Douglas fir on the Moray Estates in mid May. Leading timber out behind a Gremo harvester was the Swedish machine manufacturer’s new lightweight forwarder. Also, German manufacturer Pfanzelt demonstrated the Moritz Fr50 mini felling tractor, and the Alstor 840 Pro small-scale forwarder was in operation, as Hilary Burke reports.

LAST summer, Scott Burton (SB Forestry Ltd) supplied a new Gremo 750F forwarder to thinnings contractor Simon Simpson. Gremo engineers had based the design of the new machine on the tried-and-tested 1050F forwarder and presented it to the public at Sweden’s Elmia Forestry Show in 2017.

There was a demand from forest owners in southern Sweden for a light forwarder with reduced ground pressure. Speed over the ground, efficient fuel consumption and payload capacity would still have to combine to make the new machine an economically viable forwarding unit. Weight reduction – mainly by judicious use of high-strength steels – had lowered the overall weight to 10.5 tonnes, yet the 750F could still transport 8.5 tonnes of timber. 

The prototypes had been thoroughly tested in the woodlands around Gremo’s manufacturing facility at Ätran in Halland Province. Thinnings contractors throughout southern Sweden would soon be supplying their feedback, as the new forwarders entered revenue-earning service. Retention of all the advantages of a full-sized forwarder, in terms of ergonomics and comfort, was one of the initial positive responses. Within a few months, the Gremo 750F was provoking interest throughout Europe and beyond.

Gremo’s Roger Edström explained the company’s marketing strategy. He said: “We are coming back to the Irish market, after the problems they had with the financial crash of 2008, with Liam Burgin as the dealership holder. Here in Great Britain, where we had a good market share 20 or 30 years ago, we now have Scott Burton. The lightweight, low-impact Gremo machines have a great future here.

“I have a very good partner in Japan and we have delivered three new forwarders to that market in the space of one year. Germany is very close for us and I deal personally with sales over there. But we need a good understanding with our dealers to build confidence. They must work the Gremo way. Our customers are our business partners.”

Out on the forest floor, Lars Ryttberg loaded timber aboard the 750F for delivery to the roadside. Contracting for 30 years in southern Sweden, mainly as a harvester operator, his last four machines had come from the Ätran machinery manufacturer. The loyalty has been rewarded. When Gremo needed a test operator, trainer and instructor, Lars Ryttberg was given the opportunity.

Lars admitted that even with a full load aboard, the 750F feels surprisingly nimble and responsive when compared to the heavier generations of forwarders. The Cummins QSB 4-cylinder 4.5 l common rail engine produces 164 hp (120 kW) at 1,900 rpm. It is, however, surprisingly quiet. Governed by the manufacturer’s GreControl management system, the variable hydrostatic transmission ensures that the 120 kN tractive effort is applied smoothly and steadily. The 105 cc variable hydraulic pump provides ample supply for the Cranab FC53 loader even when working at its 6.5 m maximum reach.

Options are available. While the minimum machine width of 2.4 m is achieved with 500 tyres, many operators will see the advantage of working with ‘600s’; machine width is increased by only 60 cm. Gremo’s ‘active bogie’ system can be fitted to bring an increase of traction to the front of the machine where steep slopes are often encountered. The same system will also act to lighten the load on the fore end where patches of soft ground need to be traversed.

A couple of hundred metres to the east, as the ground dropped gently towards the banks of the River Findhorn, the Gremo 1050H harvester and SP 451 harvesting head worked through windthrown timber and the standing crop to form a main extraction route. The SP harvesting heads have long been a popular option for Gremo harvesters, with many Swedish contractors sharing the workload between different-sized heads. In smaller crops, the lighter attachments operate very efficiently, but offer a considerable reduction in fuel usage.
Gremo’s new harvester development, the 1058H, is currently undergoing forest trials. The innovative weight reduction system has again been implemented, this time to allow a considerable increase in power in a similarly sized harvester. Kaj Hoof, of Loggtech AB, sees an opportunity for the Viking harvesting heads his company produces to make their mark in UK forestry harvesting operations, with Gremo being just one of the machine ranges suitable as carriers.

SB Forestry Ltd is the dealer for Loggtech AB in the UK. Both the larger Viking 650.3 and the lighter Viking 625.3 heads feature four double-edged wrap-around moving de-limbing knives and one fixed knife. Delimbing force is governed by the feed wheel motor options chosen and twin-speed motors are standard in the heavier 650.3. Top-of-the-range de-limbing force is 28.7 kN for the bigger head fitted with 940 cc motors. For regular cutting of smaller, finer-branch stems, the 462 cc wheel motor option fitted to the 625.3 can produce outstanding results and furnish significant fuel savings, according to Kaj Hoof.

Viking harvester heads are produced in Alfta, a town in the east of Sweden with a proud forest machinery heritage. Österbergs Fabriks AB produced a range of innovative forestry implements in Alfta, culminating in the production of Ösa forwarders and harvesters. Down in the west, just north of Gothenburg, in the village of Dingle, Lars Jannsen set up his business, Bohus Traktor, in the mid 1960s. The conversion of the business from agricultural to forestry engineering took place around three decades later.

The first Alstor 8x8, as it came to be called, was a timber forwarder derived from a small 8WD utility vehicle designed primarily for use in emergency situations. The simply designed mini-forwarders were an immediate success with small woodlot owners, who were keen to thin their young woodlands themselves. One significant bonus for most customers was the availability of the units for other light farm and forest duties.
Shropshire forestry contractor Nathan Home took delivery of one of the early Alstors 20 years ago. Now contracting with full-sized harvesting machinery, his business has always had one or two of the Swedish mini-forwarders in the fleet. The basic reliable design of the earlier units has always made them readily saleable on the pre-owned machinery market. 

While the standard mechanical gearbox variants are still available, the Alstor 840 Pro represents a step up in the Dingle-based company’s range. The hydrostatic transmission, with lockable differentials, provides permanent 8WD in two speed ratios. A Parker flow-sharing valve ensures the power (25 hp) of the Kubota three-cylinder diesel engine is directed efficiently to the hydraulic systems in operation. The unladen weight of the machine is 2.3 tonnes, with a maximum payload of three tonnes.

The new design allows for the fitment of the smallest of the Tapio stroke harvesting heads, the 160. The unit weighs only 215 kg and requires a flow of 40–60 l/min @160 bar.  Chageover from forwarding to harvesting duties takes in the region of 15 minutes, so a one man/one machine harvesting operation is a viable working option. The Palms 2.50 timber crane has a reach of 4.98 m and a lifting moment of 330 kNm at maximum extension.

Home Forestry’s Alstors have been kept busy both in the company’s own woodlands and on contract work. With tree-planting initiatives seeing increasing areas of new woodland coming to the thinning stage, Nathan expects the demand for the mini-forwarding system – and the harvesting option – to see a steady increase. Customer demand, too, was instrumental in persuading German machinery manufacturer Pfanzelt to develop its remotely controlled ‘mini felling tractor’, the Moritz Fr 50.
The firm’s Peter Voderholzer explained that winching felled trees to the officially designated extraction routes now common in German forests was originally seen as the machine’s primary task. The track-mounted unit is fitted with a winch of four tonnes pulling force and a cable drum of 120 m capacity. Its use in assisting directional felling and takedown of hung-up trees would also be invaluable to the tree feller. The generous tool-carrying capacity can accommodate chainsaws, fuel and all the tools and felling aids the average forest worker may require.

Pfanzelt’s existing customers were consulted during the design stages and supported the concept. Many, however, would have liked to see the machine’s envelope of operation expanded as a multi-purpose attachment carrier. The Pfanzelt engineers complied with the request. When not on tree-felling and winching duty, the Moritz Fr 59 can be employed on ground preparation and forest management tasks. Equipped with a mulcher, the machine has been particularly successful for clearing invading scrub and natural regeneration below transmission lines.

Attachments are PTO driven, which eliminates the possibility of overheating the hydraulic oil in the compact machine. The tracks can be hydraulically widened as work progresses to increase stability on side slopes, and a 300 mm ground clearance eases progress across the forest floor. Both traction and cable winch drive are controlled from the remote-control console, as are engine speed and cable speed.