Winch-assisted steep slope harvesting has come to South Africa for the first time, with two Ponsse Cobra wheeled harvesters doing the business in the KZN Midlands and Melmoth in Zululand. The harvesters are paired with Ponsse forwarders, a Ponsse Bison in the Midlands and the Ponsse Elephant King in Melmoth.

These purpose-built machines take steep slope harvesting to the next level as they can work safely and productively on slopes up to 70% or more, depending on the ground conditions.

The machines are designed and manufactured by Ponsse of Finland and supplied and supported in South Africa by MTS Parts of Mbombela (Nelspruit). They are operated by leading Mondi contractors, Cintasign in the KZN Midlands and Mooiplaas Forestry in Melmoth.

Two experts in steep slope harvesting and Ponsse harvester operations and maintenance recently visited South Africa for two weeks to provide the contractors' harvesting teams with theoretical and practical training on steep slope harvesting. 

Ponsse Training Designer Anne Harkonen and Product Trainer Antti Hynonen spent a week working with each contractor. They covered the theoretical aspects of machine set-up, maintenance and operation, safety and planning in the classroom, followed by several days in the field.

Their objectives were to enable the contractors' harvesting and technical teams to thoroughly familiarise themselves with the machines so that they know how to maintain and operate them properly and achieve maximum productivity without compromising safety.

The Ponsse Cobra is a versatile machine 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 exceptionally well balanced even in rough and uneven terrain, ensuring maximum operator comfort and safety.

Chris Odendaalof MTS Parts invited WoodBiz Africa & SA Forestry to the Midlands to watch the Cobra in action on a steep slope in Mondi's Newlands estate under the watchful eyes of the Ponsse trainers Anne and Antti. 

The visit was in the middle of an intense wet weather spell following days of torrential rain that made ground conditions wet and muddy. The Ponsse Cobra was fitted with wet-weather tracks, and a powerful Herzog Synchrowinch tethered to a sturdy tree stump at the top of the slope.

The experienced Cintasign operator at the controls, John Yende, was understandably apprehensive but quickly got into his stride once he started working his way down the slope. When tethered, the winch maintains a constant tension on the cable as the Cobra moves down the slope, allowing the operator to focus 100% on felling, de-barking and cross-cutting the logs with smooth precision.

Anne explained that the machine must be able to work on the slope under its own braking system. At the same time, the winch merely provides 'assistance' – an added safety feature.

The Cobra was fitted with an H7 Euca harvesting head that completed the de-barking process in one clean pass that complies with Mondi's requirements. It achieved this without damaging the timber, thus minimising fibre loss in-field.

Cintasign's site manager, Jason Mennell, explained that they use excavator-based harvesters on flat terrain and will use the Ponsse on the steeper slopes. Because of its versatility, it can also work productively in flatter areas when required, giving the harvesting team more flexibility within their harvesting fleet.

One of the most significant advantages of deploying a mechanical harvester such as the Ponsse Cobra on steep slopes is safety, as the alternative is manual felling and processing with chainsaws, which comes with significant risks.

This first operation on a steep and slippery slope was successfully completed, and everyone involved went home happy with the day's work. Anne and Antti's next stop was Melmoth, where they spent a week training the Mooiplaas Forestry team.