Zell's long reach: this Northern Alberta contractor is developing the skills and tools for such mixed wood prescriptions as understory protection to add to his full-service bag of tricks

Canadian Forest Industries, Apr 2003 by Tice, Bill

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Alberta logging contractor Les Zeller has become somewhat of an expert on understory protection. Zeller has been perfecting the practice since 1996 and has fine-tuned the procedure by considering such variables as wind direction and road placement, and by implementing new types of harvesting equipment.

"Back in the winter of 1996/1997, Vanderwell Contractors from Slave Lake asked us if we were interested in doing a trial that involved protecting some understory in the Calling Lake area, which is about 70 kilometres north of Athabasca," explains Zeller, owner of Zell Oilfield Services. "We completed that project and everyone involved was pleased, so we started to plan some other understory protection projects for down the road and we have never really looked back."

Mixed Wood Tactic

Understory protection is used in mixed conifer and deciduous forests as a way to promote rapid growth of the more valuable conifer trees, while still harvesting marketable deciduous species like aspen. Harvesting is carefully planned and completed mechanically in strip patterns.

In most cases, the trails, or machine corridors, are 6 metres wide. On either side of the corridor, loggers harvest a 9-metre-wide strip, leaving most of the coniferous trees and removing most of the deciduous ones. A 24-metre buffer of deciduous trees is then left before the pattern is repeated again. This is called a two-pass system. In five to seven years, the buffer is also harvested. In a one-pass system, a wind buffer of only 5 metres is left and it is not harvested until the conifer is mature.

"The whole idea behind understory protection is that you take as much deciduous as you can while leaving behind enough that the young conifers that make up the understory are protected from wind," Zeller explains. "The deciduous trees that you are leaving behind are higher than the canopy of the coniferous, so the conifers are protected from the wind, but light can get in to promote growth. In most blocks where we use understory protection, we are removing 83% of the deciduous trees, while leaving 17% for protection of the young coniferous trees."

Zeller says that in addition to protecting the standing timber from wind and subsequent blow down, the advantages to understory protection are numerous.

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"When you have a mature deciduous canopy and a coniferous understory, the natural mix of the stand is moving toward conifer. If you simply go in and clearcut everything, the stand will come back as deciduous. By removing much of the mature deciduous, we are helping the stand move toward coniferous while still having a small percentage of deciduous, as would happen naturally, and you have the added benefit of not having to invest a lot of time and money in silviculture. As an added bonus, you can commercially thin the stand in 15 years and you will have new deciduous trees ready to harvest at the same time as your coniferous trees, creating a good mixed stand."

Learning Process

Zeller says he has learned something every time he has taken on an understory protection project, and through trial and error, has improved the process every year.

"After we finished the first project up in Calling Lake, we analyzed it and said, 'what can we do better?' and we have been learning ever since."

Zeller concedes they had some problems with blow down the first year they tried the project because they did not take wind direction into account when they planned their roads. The winds in the area are generally northwesterly gusts, so the following year Zeller created the roads north to south with access trails for skidding. In addition, they created offsetting angle exit and entry points at the end of the trails so that the trees are not exposed to direct winds, and they made narrower roads with landings rather than wide roads, which helps to eliminate the funnel effect. The trails were also narrowed to 6 metres.

Zeller realized that his crews had to be very careful when working with a feller buncher.

"Because the trails were narrower, we realized that we needed a machine with a longer boom and minimal tail swing," he explains. "This combination was hard to find, because as the machine manufacturers will tell you, if you have more reach, you require more counterweight on the back end, which means the two are working against each other."

While looking for the right machine for the job, Zeller started talking to Gilbert-Tech, a Quebec-based company with an office in Prince George, BC.

"I met the Gilbert-Tech representative at a trade show in Grande Prairie, AB, back in 2001," Zeller says. "I was looking at their head and told him that what I really needed was a telescopic boom. It turned out they had been working on a prototype and had some photos. We worked with them for about a year before actually putting their boom and high rotation head on our Timberjack 850. Gilbert-Tech now has a longer stick than anyone else, and it is compatible with our 850, so last spring we finally gave it a try. We used it for an entire project back in Calling Lake, which ran through August, and our operators were really happy with it. We had an additional 5 feet of reach, and our operators thought it was much easier on the undercarriage of the 850."