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Assisted Logging

Tigercat is on both ends of the rope at Mecharv’s steep slope operation in Araucanía, Chile.

— Paul Iarocci

A 635G skidder working with the 120 winch assist.
A 635G skidder working with the 120 winch assist. The 120 has full travel signal integration with Tigercat carriers.
Mecharv S.A., based in Los Angeles, Chile, is a large harvesting contractor employing over 260 people. The operations span a vast geographic area, including the regions of Maule, Biobío, and Araucanía. While the company harvests both pine and eucalyptus, most of the company’s 1,6 million cubic metre annual volume is comprised of eucalyptus.

Mecharv has seven contracts with Chilean forestry company CMPC. Two of the operations are classified as steep slope, employing yarders. Two infield chipping operations work on flat terrain up to slopes of 50%. The company also has a CTL (cut-to-length) harvester-forwarder operation and a loading contract. Up until now, a winch-assisted ground-based crew has been operating under a contract specifying up to 50% grades.
General manager Freddy Rebolledo is one of eleven partners in the 24-year-old company. “In Chile, a steep slope is historically where the traditional yarders used to work – up to 100 percent or 45-degree grade,” says Freddy, explaining that Mecharv is equipped to take on any steep slope contract as long as no more than ten percent of the terrain exceeds 100% slope.
(L-R) Freddy Rebolledo, General Manager; Carlos Cerda, Maintenance Manager; Manuel Cid, Operations Manager.
(L-R) Freddy Rebolledo, General Manager; Carlos Cerda, Maintenance Manager; Manuel Cid, Operations Manager.
Mecharv’s harvesting operations work around the clock. Most of the crews work double twelve-hour shifts, seven days on/seven days off, or Monday to Saturday triple eight-hour shifts. Because of Mecharv’s expansive area of operation, a logistics department manages housing needs for crew members, greatly reducing potential commuting times while increasing worker safety. The modern camps are comfortable, secure, and well maintained.

World’s first 120 owner

In March 2025, Mecharv became the first company to purchase a Tigercat 120 winch assist. The machine was slotted into a steep slope yarding jobsite near the town of Capitán Pastene in the Araucanía region.

“Steep slope harvesting here is divided into ground extraction with skidders and aerial extraction with yarders. In summer, the skidder works on slopes of up to 60% grade. From 60% and up to 110%, the extraction is done with yarders,” Freddy explains. Whether or not the skidder is winch assisted depends on the season, which directly impacts soil conditions. In winter, the skidder is winch assisted once the slope exceeds 30%, and in summer, the cutoff is 50% grade. The same guidelines apply to track-based feller bunchers and shovel loggers.

Freddy explains that in the past, many harvesting contracts limited skidder extraction to grades under 50%. Everything over 50% had to be extracted with a yarder. “In our contracts, we discovered that some inefficiencies existed with the yarder. Mininco [CMPC] also discovered this. We realized that if we can get up to 100% slope with a skidder, we will produce more volume at a more competitive rate. It will require investment in more winches, but Mininco will have more volume at a lower cost.”

Mecharv currently owns more than 50 Tigercat machines, and Freddy notes the expected rate of machine availability is 85%. Freddy explains that a yarder on average works productively about 160 hours per month out of 295 total available hours, or around 55% availability. Moving a yarder to a new location on the cutblock is a time-consuming process. In Chile, where topography and other constraints frequently limit road system design, these set-ups are also costly in terms of interruptions to other operations—including processing and loading trucks—when access roads are temporarily blocked.

Limited landing sizes also regularly challenge Mecharv’s steep slope crews. Often, the landing area under a yarder setup will literally run out of space before all the trees can be extracted. The result is a situation where the yarder moves back and forth along the road, allowing the decked trees to be processed and loaded, before returning to continue the extraction. It results in even more frequent moves, more interruptions and road blockages, and further reductions in yarder availability.
The sloping tail profile allows the 120 to anchor in tight spaces along road banks.
The sloping tail profile allows the 120 to anchor in tight spaces along road banks.
The 120 winch assist is a different animal altogether. Compact and highly mobile, it can pick up and move to a different location very quickly. Even though the production rate of a swing yarder (30-33 cubic metres per hour) is more than a cable-assisted skidder can achieve, the yarder can’t compete with a cable-assisted skidder in terms of productive hours. Freddy says that in many of Mecharv’s extraction scenarios, median distance is 150 metres and maximum distance about 300 metres – a working range where the 120 has a clear advantage. Beyond 400 metres, a swing yarder becomes the optimal extraction option.

Freddy has experience with several different winch assist machine brands and says each system has its own set of pros and cons. For example, one competing system has a slow line speed that is well suited to the felling machine but too slow for the skidder. Another system has enough speed to work effectively with a skidder but is large and cumbersome to place in tight quarters. Some winch systems work adequately with different brands of machines but do not work really well with any. The 120, on the other hand, has full travel signal integration with Tigercat carriers. “The way it works with other Tigercat machines, it’s like a brotherhood. They are well synchronized,” says Freddy.
The pivoting sheave allows the assisted machine to work well off centre, resulting in increased operational flexibility and reduced number of set-ups.
The pivoting sheave allows the assisted machine to work well off centre, resulting in increased operational flexibility and reduced number of set-ups.
Unlike a skidder, when hooking up the 120 to a track machine, winch speed is no longer the factor that determines overall productivity. Good performance comes down to stability and power to assist 40-tonne feller bunchers and shovel loggers in demanding terrain conditions. The 120 provides the best of both worlds – speed when required and power when demanded. By having full control of the engine and hydraulic system, the 120 winch automatically matches the speed of the assisted machine while maintaining line pull.

“Engine speed, dedicated winch pump flow, and winch motor displacement are automatically regulated to meet the demand from the winch, allowing the operator-set line pull to be sustained at higher travel speeds than winch-assist machines running at constant engine speed,” says Andy Hoshel, Product Manager for Tigercat cable logging systems. “This regulation continues up to the limits of engine speed, engine power, or pump displacement. Once one of these limits is reached, the 120 will automatically reduce line pull to match the higher line speed, ensuring that the rope stays tight. As the assisted machine slows down, line pull will again increase, limited by the operator-set maximum.” This system ensures that the 120 can provide all available engine horsepower to the winch when speed or line pull demands are high, increasing the productivity of the assisted machine.

A lot of thought went into the design of the cable tensioning system. “We drive the top sheave on the boom in order to pull a small amount of tension between the sheave and the winch drum,” says Andy. “This keeps the line tight, which makes the rope spool better. When you spool the line without tension, you get gaps and bunching in the middle, ultimately creating wear and shortening rope life.”
skidder with cable assist
Cable tension management. According to product manager Andy Hoshel, engine speed, pump flow, and motor displacement are automatically regulated to meet the demand coming from the winch, allowing the operator-set line pull to be sustained at higher travel speeds.
Another big advantage of the 120, especially on small and congested landings is the pivoting sheave. This allows the tethered machine to work well off to the side of the winch assist machine, up to 35 degrees in each direction – more than double the working angle of competing machines. It allows for less frequent repositioning and the ability to deck wood further along the road. The 120 has a sharply angled sloping tail that further assists with machine placement on narrow mountain logging roads.

Freddy says that, as always with Tigercat, a primary advantage of the 120 is that it is a tough, robust machine. He finds some of the competing machines to be “too delicate, too electronic. And the fabrication is noticeably better from Tigercat.”
The 855C carrier equipped with the 573 head processing Radiata pine. It is a challenging job to manage many different products with limited decking space.
The 855C carrier equipped with the 573 head processing Radiata pine. It is a challenging job to manage many different products with limited decking space.

Processing with the 573

Other Tigercat machines on the jobsite included an LS855E configured with a feller director boom set and equipped with a 5195 directional felling saw, and the 635G skidder handling extraction duties in tandem with the 120. At roadside, an H855E harvester equipped with Tigercat’s new 573 harvesting head was processing timber averaging 0,8 cubic metres to the stem with an average diameter of 40-45 cm. A new acquisition for Mecharv, the 573 is the company’s first experience with a Tigercat processing head and had acquired 500 hours of operation by March 2025.

The mill requirements add a layer of decision-making for the processor operators. Tigercat Product Support Representative Pedro Venegas explains that “the processor operators have to visually determine if the tree was pruned or not and the length that it is clean and free of knots.” The mill specifies two clean products with a minimum 280 mm diameter. The preferred and most valuable product is a 5,3 m clean log. “If it is not possible to get a fully pruned 5,3 m log, then the operator must cut a 2,65 m pruned log. If the operator cannot produce a pruned 5,3 m log, we sometimes see the operator feeding the log backwards to get the next best possible product.”

Continuing down the bucking list, after the two clean logs, the mill specifies two different 5 m logs, depending on the diameter, followed by two different 4,1 m logs, also dependent on diameter. Next is a 3,45 m log. “It's not a common one, but it is on the list. So the operator can enable or disable some products,” Pedro explains. “And then we have the pulp that is 2,44 m and less than 160 mm diameter. But the operator can also cut a pulp log if a tree is damaged or broken, regardless of diameter.” Despite the many sorts, the operator decision making, and the restricted landing sizes, the 573 is averaging a production rate of 60 cubic metres per hour.
573 saw box close up
Freddy Rebolledo points out that the 573, Mecharv’s first experience with a Tigercat processing head, is durable and accurate.
CMPC quality control team members routinely visit the operations, sampling length and diameter measurements to ensure that timber is optimized to the bucking list and that the processing head is operating within the required +/- 25 mm (1 in) tolerances. CMPC also has very strict rules regarding the length and diameter of material that can be left as slash, to maximize the recovery of pulpwood and minimize waste fibre.

In terms of size and capacity, Freddy likens the 573 to a Waratah 623 or Ponsse H9. “The main advantage is accuracy in measurement,” says Freddy. “It is also more robust. I would say that some of the other heads are more fragile in terms of structure and materials and suffer from premature wear.”

Field day

Tigercat dealer Latin Equipment Chile, along with Mecharv, organized a demonstration day to show off the capabilities of the 120 and the 573 processing head. Approximately 30 representatives from several prominent Chilean harvesting contracting companies attended the demonstration at Mecharv’s worksite. For one hour, the 635G skidder and the 120 winch assist performed several extraction cycles. Mecharv then demonstrated the 573 head for the guests, followed by a snack onsite and lunch in the town of Capitán Pastene.

Carlos Vera, Sales Manager at Latin Equipment Chile, comments, "It was a memorable day for our team and for Chile’s forestry sector. We are truly grateful for the effort and excellent organization shown throughout this visit. Our sincere thanks to CMPC, Mecharv, all our customers, Tigercat, and of course, the Latin Equipment Chile team for making this successful field day possible.”
group image
Around 30 contractors attended the field day hosted by Mecharv and Latin Equipment Chile on the CMPC jobsite.
Carlos says that he and the sales and customer support team present at the event received only positive feedback from the clients in attendance. “Everything went smoothly and exactly as planned,” says Carlos. “This outcome fills us with pride and reaffirms the mature stage our company is experiencing within the Chilean forestry market. For over ten years, we’ve been the benchmark in steep slope operations, and we continue to set the standard in this demanding segment. We will continue to look ahead and ensure that we keep leading the way.” Carlos adds that the 120 demonstration ended with an excellent result. “As the cherry on top, we wrapped up the field day with the immediate sale of a Tigercat 120.”

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