Clear-felled steep slopes in Kwa-Zulu Natal.
Steep slopes are one of the new frontiers of mechanised harvesting systems as forestry companies and contractors seek to find the safest, most productive and cost-effective means of harvesting timber.
Steep-slope harvesting machines require exceptional power, balance, and control, as well as a highly skilled operator. However, they also need a system for tethering the machine to a stable point at the top of the slope to ensure the safety of both the operator and the machine.
There are various tethering systems in use around the world, including standalone winches and winches attached to excavators stationed at the top of the slope.
Synchrowinch
Leading the way in this regard is Ponsse, the Finnish manufacturer that has taken steep slope harvesting to the next level. Key to the success of the Ponsse steep slope machines is the built-in Herzog Synchrowinch that is synchronised with the transmission of the harvester or forwarder, allowing it to automatically spool in and out as the machine works across the slope.
This enables the operator to focus on felling, processing, and extracting trees. The machines need to be able to operate on the slope under their own braking system. At the same time, the tether provides increased traction and serves as an additional safety net.
Because the winch spools automatically from the machine end, the cable is always static, which reduces wear and tear. It also provides extra traction, resulting in less soil damage.
The steep angle of the slope presents no challenges for Mooiplaas Forestryand Cintasign Forestry contractors.
Cobra clear felling at an angle
Two highly experienced harvesting contractors operating in KwaZulu-Natal have recently invested in winch-assisted Ponsse Cobra wheeled harvesters, which are capable of working safely on slopes of up to 70% or more.
The Cobra harvester enables Cintasign Forestry and Mooiplaas Forestry contractors to deploy fully mechanised systems to safely fell, process, and extract timber productively and cost-effectively. Mooiplaas added the Ponsse Elephant King forwarder, also fitted with the synchrowinch, to its order.
An advantage of the Ponsse Cobra is its versatility. It’s ideal for cut-to-length clear-felling or thinning operations. It is equally adept working in gum or pine on flat or steep slopes, thanks to the design of the bogeys and the levelling capabilities of the crane base and operator cockpit. It’s extremely well-balanced, even in rough and uneven terrain, ensuring maximum operator comfort and safety.
The machines were delivered in February this year. Ponsse harvesting experts from Finland spent time in South Africa providing specialised theoretical and practical in-field training to the contractors’ operators and maintenance teams, familiarising them with the machines and helping them understand the dynamics of working on steep slopes.
Cintasign Forestry
“It’s meeting all of our requirements”, comments Quinton Preen of Cintasign Forestry, which is contracted to do harvesting in the KZN Midlands area for Mondi.
Quinton is a second-generation logger with 30 years of experience. His father, Don Preen, began forestry harvesting in the 1950s, using bow saws and then chainsaws. Quinton joined the business in 1995.
Mondi requires a full compartment mechanised solution, which means the contractor must harvest every tree on the plantation mechanically, explains Quinton.
Cintasign uses the Ponsse Cobra on steep slopes and flat areas alongside their track-based excavators, as there are not enough steep slopes to keep them busy full-time. Thus, the Ponsse Cobra gives the Cintasign harvesting team more flexibility within their harvesting fleet to cover all the tasks required to meet the contract requirements.
They also have a Ponsse Bison forwarder extracting timber from in-field areas and handling short-haul operations.
The Cintasign team identified three operators for training on the Cobra, and they are already working comfortably on slopes of up to around 60%. Quinton says the Cobra has the potential to work on slopes of up to 70% or 80%, depending on the ground conditions. Still, operators need a bit more experience to become comfortable on such slopes.
He says that the Cobra, which is equipped with a Ponsse H7 Euca head, matches the productivity of excavator-based harvesters on small trees; however, “We get 20% to 30% better performance in big tree sizes compared to the tracked excavators”.
Safety is a significant advantage of the Cobra when operating on steep slopes. It comes equipped with a powerful Herzog Synchrowinch, which is tethered to a tree stump at the top of the slope while in operation. The Cobra works on the slope under its own braking system, while the winch merely provides assistance.
What prompted the Cintasign team to opt for the Ponsse Cobra? Quinton says they have a Ponsse Bison forwarder and are using Ponsse H7 Euca heads on their excavator-based harvesters, so it makes sense to stick with the same equipment manufacturer.
The Ponsse machines operating in South Africa are well supported by MTS Parts. “The guys have done pretty well”, Quinton comments.
The Operator decides on the best tether point.
Mooiplaas Forestry
Dewald Martens of Mooiplaas Forestry, who contracts for Sappi and Mondi in the Melmoth area of Zululand, has also invested in a Ponsse Cobra, paired with a Ponsse Elephant King forwarder.
Dewald’s father started the forestry contracting business back in 1982, and he joined the company a few years later. His brother Lukas is also involved in the business.
Dewald says the Cobra and Elephant King are an ideal solution for Mondi’s preference for fully mechanised harvesting systems.
“We’re taking out all the timber mechanically, that’s the way we are going”, says Dewald. “The Ponsse Cobra and Elephant King are a nice combo for the steep slopes”.
Both machines are equipped with synchro-winch systems. When winch assistance is required, the operators park the machine, attach the winch to a sturdy tree or stump at the top of the slope, and are ready to go.
Dewald says that while the Cobra is a cost-effective and productivity-enhancing solution for steep slopes, it also outperforms the other machines in their fleet by 10% to 20% on flat areas, making it a versatile option.
Dewald said they have received good support from the Ponsse steep slope harvesting experts, who spent a week on site soon after the Cobra was delivered in February this year.
“We’ve had good support from them on the training side, and they are coming back again in a few months to do more training”, says Dewald. “The machines are doing what they are supposed to do, and we haven’t had any issues”.
The Ponsse Cobra’s Herzog Synchrowinch tether increases traction and safety.
MTS Parts
Chris Odendaal and his company, MTS Parts, distribute and support Ponsse machines in South Africa. Chris says the Cobras are the first purpose-built, winch-assisted machines operating in the country.
“They are revolutionising steep slope harvesting around the world, improving the safety and productivity of forestry operations that have posed considerable challenges for growers and contractors”, Chris comments.
Chris Odendaal, MTS Parts – 082 575 7447
Visit: www.mts.com; www.ponsse.com
Read more – https://www.woodbizafrica.co.za/june-2025-issue-49/9/