KING OF THE STUMP

Keeping weevils at bay has always been a constant battle for forest managers. For years, chemicals have been the go-to method for reducing populations. But with many pesticides set to be banned over the next few years, people have started looking for an alternative. Enter Kingwell Holdings’ Bogmaster LGP Stump Auger.

Living in the stumps of old trees and eating young plants, Large Pine Weevils (Hylobius abietis) were proving a problem for Phil Di-Duca, experienced Forest Manager and owner of Kelpie Woodlands. At the Rosal Forest site in the Scottish Highlands, the insects were a major barrier to restoration. Badly damaged in Storm Arwen, plans to bring the 2,400-hectare forest back into use for commercial timber through harvesting and replanting were being put at risk by high populations.

With tighter controls on weevil pesticides being rolled out by the Scottish Environment Protection Agency (SEPA) over the next few years, Phil started searching for a new solution. “He saw a post about our Bogmaster Stump Auger on LinkedIn,” says Justin Kingwell, company owner of forestry operations specialist business Kingwell Holdings. “He got in touch and arranged for us to go out and start several weeks of trials.”

COMMERCIAL CLEARING

Justin is no stranger to innovation. Having started his business, Kingwell Trees, in 1987, his 35 years of experience working on forest management projects across the UK have led him to push the boundaries of industry machinery. To improve the quality and efficiency of his timber, stump grinding, shredding, and site clearance services, he’s adapted or built shredders, mulchers, stump grinders, and other specialist machines to meet his needs.

The same goes for the Bogmaster Stump Auger. Working alongside Robert Little at their group company RGL Forestry, Justin wanted to create a machine that could clear sites efficiently. "There was nothing commercially available that could get rid of stumps in sufficient volume or speed," he explains. "Existing machines were either too slow or didn't have enough power. We knew a lot of chemicals used to control weevils were in the process of being withdrawn, so we wanted to do something about it and built this machine before the rest of the market."

MASTERFUL MACHINERY

Having worked as a forestry clearance and site preparation contractor in Scotland and northern England for decades, Justin knew Bob would be the right man to build a new auger machine. He says, "I've known Bob, his engineer Wul, and his son Graeme for a long time, and they originally created the Bogmaster. It was built to carry a mulching head and was mainly used on large-scale wind farm and habitat restoration clearances.

“With standing trees and vegetation now mainly harvested for biomass fuel and mulching largely restricted to soft or remote sites, this type of work is not as common as it used to be. That’s when we saw an ideal opportunity to convert the machine to a stump auger."

Custom-built by the RGL team, the Bogmaster LGP Stump Auger is based on a 27-tonne tracked excavator carrier. With a Mercedes engine offering more than 400 hp, very powerful hydraulics, and larger tracks, the machine exerts just 3 PSI of ground pressure. This means it can work well on soft, rough, or rocky ground efficiently without damaging the surrounding environment.

Resembling the original digger, the machine is raised up on a high walker carriage so it can operate without the risk of partial submersion in water or soft ground.

MIKE QUIRIE OPERATOR Kingwell Holdings Ltd.

The power of the attachment makes dealing with abrasive ground easy too. Driven by high-performance hydraulic pumps and a super-efficient cooling system, the stump auger can clear up to 1.5 hectares of stumps per shift without any downtime. Breaking them up into fragments of around 30 mm thick, any embedded rocks can also be pushed aside with little or no wear on the machine. This means blade life is measured in weeks, not days.

THE FUTURE OF FORESTRY

By breaking stumps down into the ground, the machine removes weevil habitats and prepares the ground for replanting. No brash raking or mounding is required, and wood shavings are turned into the soil, creating more fertile ground and reducing the need for chemicals. Drainage is also improved with old ploughing furrows broken up, runoff minimised, and planting positions for new trees clearly marked.

Using the Bogmaster has brought massive benefits to the Rosal Forest project, as Phil explains, “The forest is certificated under the UK Woodland Assurance Scheme (UKWAS). This means there’s a requirement to minimise chemical use across the forest. Currently, the only other alternative to a non-chemical approach is to leave the harvested areas 'fallow' for up to five years to reduce the weevil numbers.

“Financially, this loses four to five years of growth, and the sites degrade with the loss of the nutrients and mycorrhizal fungi needed for new trees within the soils. Sites can then weed up, which has to be chemically controlled, with additional fertilisers needed. The operation does not remove all the potential weevil breeding or feeding sites but keeps them at a manageable level without chemical control. It is great to see Justin and his team investing in this innovative approach to protect the future of our forests.”

For Phil and Justin's other customers, this gives the joint benefits of efficient forest clearance with low establishment and maintenance costs. As Justin explains, "Phil was very pleased with the work and the fact that he could get it done at an affordable, commercial rate. As a result, we've been awarded ongoing contracts to clear each year’s harvested areas as they start commercial timber production."

Justin isn't stopping there, though. He has ambitions to bring the Bogmaster to projects across the UK so other forest managers can control their weevil populations in an environmentally compliant way. "We're looking to build more machines with the aim of getting more forest owners removing stumps mechanically rather than controlling weevils with chemicals. As more regulators look to remove pesticides from water systems and other habitats, our machine will become a more effective and commercially viable option."

As more regulators look to remove pesticides from water systems and other habitats, our machine will become a more effective and commercially viable option...