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Optimizing At Roadside

Summary: New automated delimber measuring systems like Denharco's ControlPlus II take optimizing in the bush a step farther. The system can be retrofitted to older machines.

By Jim Stirling
Copyright 1996. Contact publisher for permission to use.

The phenomenon of individual stem optimization began in the sawmill. Now the computerized technology that sustains this trend has spread to the bush and to log harvesting equipment. It makes sense. Obtaining the maximum quality, value and utilization from each tree harvested represents the optimum integra-tion between available resource, sawmill design and marketed products.

The goals of logging contractor Rosko Bros. Ltd., based in Kirkl and Lake, Ontario, reflect that integration. The company aims to recover the maximum value in wood and chips from each tree’s volume with minimal waste.

An advanced measur-ing system on the company’s stroke delimbers is helping Rosko Bros. achieve its tar-gets and provide its licencees with the quality of raw material required.

The Denharco ControlPlus II measuring system offers a range of automated functions based on tree length and diameter. Denharco introduced its ControlPlus system in 1989. This latest generation is able to determine the exact length and diameter of each stem and ascertain its profile in 1” increments before a cut is made. It accomplishes this as the delimber arms travel the stem. The Denharco system effectively optimizes the tree to pre-determined lengths dependent upon what the mill wants. It incorporates resolver devices to calculate and re-assess the stem after each cut. And it has the flexibility to choose multiples of length and value, as required.

A log doesn’t have to be put down during its controlled processing until it’s ready for piling. Company principal Joe Rosko has installed the ControlPlus II system on a Denharco DT 3000 boom delimber, matched to a John Deere 790E carrier. More recently a second system has been added to a Denharco DM 3500 one-piece boom delimber on a Cat 325.

The measuring system can be retrofitted to other stroke delimbers. Rosko is equipped to harvest more than 300,000 m3 annually with the species harvested split between 50 per cent poplar and the balance in spruce, pine and balsam. Principal licencees are Grant Forest Products in South Porcupine for the poplar, Malette Inc., in Timmins, and veneer logs are directed to Norboard in Cochrane.

Rosko operates a tree-length harvesting system, producing stud logs from stems averaging 22 cm down to an 8-cm top and a 15.2-m average length, dependant on growing sites. “We focus on using every part of the tree to get the more valuable eight-foot length studs from 99-inch logs,” says Rosko.

“We have to reduce the amounts of waste going to the mill. We don’t want Crown dues paid on waste.” Going to an 8-cm top from 10 cm can mean extracting a full-length 2x3 stud instead of a shorter length, thereby maximizing value throughout the tree’s length. The ControlPlus II’s ability to optimize and cutting accuracy of +/-3/4'' helps make the gains achievable. The DT 3000/JD 790 combo has logged more than 6,000 hours.

This has given the measuring system its most prolonged use in eastern Canadian working conditions. Rosko says the Cat 325, with the DM 3500 delimber and ControlPlus II, was added primarily to work in poplar stands. The unit is well equipped to process the larger, heavier limbed wood.

Both machines are equipped with butt-and-top saws. Rosko is a fan of the saws. “We have to trim any irregularities including flare or uneven butt cut made by feller bunchers .” He says saws do a good job especially on larger-diameter tops and in poplar where there are often forks.

He adds, using knives for slashing can cause splits down the tree . “The saws have worked out excellent. There’s absolutely no splitting. You get a perfect cut for a perfect stud,” he endorses. Some of the company’s harvesting areas are in mixed stands where multiple sorts a rerequired.

“We do lose production through the machine movements needed.” Rosko concedes the delimbing system has contributed to an overall 30 per-cent reduc-tion in production. But he’s quick to add that has to be tempered with producing superior-quality wood, maximizing the resource and creating less environmental damage.

Another contributing factor to production decline: Rosko Bros. had been used to multiple-stem delimbing, compared to the present single-stem system. Rosko says his company worked closely with Denharco to modify the ControlPlus II system to cycle more of the shorter stems the company harvests.

The system was first applied to the longer, larger-diameter trees in forests of the Pacific Northwest. He says one of the successful results of the co-operation was delivering information from the system to the operator in a manageable, user-friendly fashion.

It reduces the stress for the delimber operator and simplifies decision making.New equipment and systems require a learning curve to achieve full potential. “During our second six months we solved 80 per cent of our problems as we became more experienced with the system,” con-tinues Rosko.

The familiarity contributed to a smooth start-up for the DM 3500 delimber with ControlPlus II and Cat 325 combination. The term “automatic” describes many of the control functions and features of ControlPlus II. The system automatically decks in either top or butt alignment. It allows the operator to pre-set a sequence of up to six lengths in one combination. It has an automatic stop capability on pre-set diameters; and it has an automatic stop on up to 24 different pre-set lengths.

The ControlPlus II’s automated computerized controls have helped Rosko Bros. reduce delimber maintenance costs. The machines have boom limits on them so the trees won’t hit the bumpers, he explains. Even with experienced operators, that used to happen several times a day.

“We’ve noticed our cable life has really increased. Probably by about four times, which is very significant.” That has the accompanying benefits of less machine jarring and theassociated wear and tear. Plus it reduces stem breakage and fibre loss.

Many logging contractors in Rosko’s operating areas have switched to a cut-to-length harvesting system. Rosko is in no rush to join them. “We’re trying to avoid that,” he reports. Cut-to-length machines are smaller and have to work harder than rugged-stroke delimbers working tree length, which has an impact on the respective costs of the two systems, explains Rosko.

He adds slashers in sawmills are faster than those offered in cut-to-length systems, and stroke delimbers can work at the stump if necessary. He’s satisfied with the flexibility and performance of tree-length, single-stroke delimbing for his fibre and operating conditions, and with the help he’s received to continue improving his bottom line from Denharco’s ControlPlus II measuring system.

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