Short Cuts for Hardwood
How does using a cut-to-length harvesting method typically reserved for softwood forest operations stack up when used in hardwood forests? The merits of this method were recently put to the test at a Quebec operation by researchers from FPInnovations (FPI), a non-profit forestry research group.
|Liebherr 914/Keto 525 work a low-quality stand.
FPI researchers recently conducted on-site tests to verify the feasibility and profitability of hardwood harvesting using cut-to-length processing, as opposed to a more traditional harvesting method, which harvests the entire tree and then processes it afterwards. An FPI team, headed by Guyta Mercier, conducted the tests on woodlots located just outside of Quebec City late last year.
Due to the high level of interest, the number of participants was capped at 30. “Initially, we thought the tests would attract only about 10 people, because December is not usually the most popular time of year to organize a forestry tour,” Philippe Meek, a researcher from the team, recalls.
“Contractors had already achieved some success by taking advantage of the cut-to-length wood harvesting method and we were hoping to encourage others to follow suit,” Meek explains. “During our feasibility study, it was important to consider that processing a large hardwood tree with a multifunctional head requires lengthy hours of training and practice by the harvester operator, and initially the work requires more supervision,” he says.
|left: In Duchesnay, David Boisvert, from Vexco, talks about plant requirements concerning the bucking of hardwood logs. Holding the megaphone: Guyta Mercier.
But those drawbacks could be outweighed by three significant advantages associated with the cut-to-length wood harvesting method: the cost benefits of integrating processing with harvesting; the decrease in damage to the trees near the machine’s path; and the reduced ground disturbance that results.
First Stop in a Private Forest
Meek tells Canadian Forest Industries that the first stop during the forestry tour was to a large private forest near the town of Stoneham, which consists primarily of hardwood trees, and where a small volume of softwood trees is harvested as well. Nearly 40 years ago, the first processing on the site was done using a “diameter-limit cutting” method. Meek describes the area as a mixed stand, and says that many of these trees are young and need to be preserved for future harvests.
Currently at this site, only about 30 to 35% of the standing volume is harvested annually, a number that is adjusted depending on what they find on the site, such as any problem or dying trees. During the tour, Luc Deslauriers, a Quebec-region forestry consultant who was along for the ride, pointed out the forest management concerns for the area, stating, “It’s great if we manage to produce mostly wood of saw- or peeler quality, but that’s not the silvicultural objective.”
For this block, Yvan Labbé, a local logging contractor, demonstrated the use of a Valmet 415 harvester, equipped with a Valmet 360 harvesting head. “For selective cuts in a private forest, this machine is perfect even if it seems small,” Labbé says. The main advantage to using a smaller machine is the reduced impact to the ground (fewer ruts) and that is something that most woodlot owners try to minimize.
Labbé’s two sons alternate shifts, which means that the Valmet can operate for extended periods. While the younger son demonstrated harvesting methods during the tour, the senior Labbé noted that if the log exceeds 18 feet in length (5.49 metres), the forwarder cannot efficiently load it. “It’s possible to have a 25-foot (7.62-metre) log if it is five inches in diameter at the small end,” he says.
To maximize the log’s value, they use an ‘improved section method’. The length of the log is cut at the level of the first large branches. The top part of the tree is usually destined to the hardwood pulpwood market, and can be cut into eight- or 16-foot lengths, or smaller. This protects the largest part of the log, in which the wood products with the greatest value are found. This part is sawn last so that the operator can maintain maximum value.
Labbé says that saw-quality wood is cut to eight, nine or 10-foot lengths. He adds that as long as there are no gnarls or other defects in the wood, the head accurately achieves the cut lengths.
Rules for Slashing
Meek cautions that if the operator is asked to rough-trim the tree up to four inches at the small end in order to maximize the full value, the costs can escalate quickly. He says that if the machinery must spend more than 90 seconds on the same tree, it’s better to leave it on the ground and let a logger finish the work with a chainsaw. “You add 0.50¢ per cubic metre to the topping costs, for only part of the work cycle, instead of wasting time on the machine, which costs $180 an hour,” he explains.
With cut-to-length processing during harvest, the machinery moves around less on site. Jean-Philippe Gaudreault, from FPI, points out that travel time is noticeably reduced: 25% as opposed to 50% for the full-tree system. “It reduces fuel consumption and it is also good for the life span of the vehicle’s tracks,” he says.
The machinery moves less because the operator takes care of the slashing, between 39% and 53% of the time depending on the site. “It’s a significant element if we want to work at night,” notes Meek. He tells us that it’s always been difficult to work at night in hardwood forests and it seems easier to consider with the CTL system.
The correct evaluation of wood quality and consideration of the residual value are the two requirements that Yvon Labbé insists on from his operators. He stresses that he never lets a new operator use the harvester until he has demonstrated a minimum of knowledge in sorting out the various species of hardwood trees. New operators on his team will first be entrusted with driving the forwarder, where they can demonstrate how well they manipulate the logs and protect the standing trees.
Meek recommends talking with the operator before sending them into the block, as he says it saves time and money in the long run. “With a tough market, the standards for sawn lumber are less sophisticated than before,” he says. “It’s easier to meet those standards with cut-to-length processing. If the guidelines for slashing are kept simple, it is possible to produce sawlogs with this system.”
Second Stop in Duchesnay
After a lunch break, the group moved to Duchesnay, to visit a block located about 30 minutes outside of Quebec City, where an irregular “shelter-wood” cut system is in place. This method is preferred in cases where there might be an insufficient number of mature trees. “This forest consists of two levels, both with heavy timber and a lot of small stems, and nothing in between,” Meek explains. “Because of this, the emphasis is placed on regeneration, and protecting seed trees along with the residual cover.” This means that you can harvest the first volume of wood, come back to harvest again 15 years later, and still leave the forest to grow for another 40 years. This type of selective harvest is aimed at ensuring constant wood production every 15 or 25 years.
|Contractor Camil Vigneault (on the left) and his son Yannick, harvester operator.
In Duchesnay, the harvest of this mixed forest is the responsibility of contractor, Camil Vigneault. Normally, every operator is accompanied by a logger who tops the trees, but during this tour, the operator tackled the job alone. Vigneault’s son, Yannick, operates a Keto 525 head mounted on a modified Liebherr excavator and readily admits that it took about a year before he felt comfortable with the partial-cut method of cut-to-length processing.
One concern of the cut-to-length method is that the roller pins might leave marks on the logs, which could reduce the wood’s value. “Usually when that happens, it’s because the tree is curved,” the senior Vigneault points out. “When the trunk is straight, there are no marks. We’ve used this technique for several years now and it doesn’t cause any problems.” During the summer, he uses a traction system with “less aggressive” rollers.
He also prefers the “improved section” method to protect the residual cover. This method improves operations when the trees with the largest diameter are enmeshed with other nearby trees. The Keto head can cut the trees at up to 25 feet (7.62 metres) in height. “It’s often a defect, the bend or a large gnarl that determines where we begin to cut,” Vigneault says.
In a 2009 study from FPI, the cost of cut-to-length harvesting ranged from $5.38 to $9.80 per cubic metre, and two other sites were evaluated at $6.53 and $6.94. The cost of forwarding, with a 12-ton forwarder travelling an average of 300 metres, came in at $6.81 per cubic metre, which is less than using a cable skidder to pull the entire trunk. “It’s a cursory analysis which must be validated depending on your context,” Meek says. “Costs for supervision, transportation and logistics may be higher.”
To bring the wood to the road, the cost of partial cutting with the standard full-tree process, including topping with a manual harvester, was estimated at $18.71 per cubic metre. Even taking the least productive site in the FPI study, the cut-to-length system was evaluated at $18.38 per cubic metre. The FPI team estimates that this cost can easily be reduced.
July 3, 2012 By Alain Castonguay
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