If one piece of forestry equipment has single-handedly modernized logging practices, it is the feller buncher. The feller buncher is a dual-function machine that has come to replace the work done by lumberjacks or fallers, namely falling and piling trees into bunches. In terms of production, feller bunchers can fall and bunch as much as 200 trees per hour, a rate that could never be matched manually.^[1] In fact, one feller buncher typically does the work of 10 to 15 men.^[2]

In addition to feller bunchers, there are also other types of felling equipment. Single-function felling machinery is only capable of directionally cutting down a tree whereas multi-functional felling equipment called harvesters are capable of felling, delimbing, bucking and stacking trees.

Contents 1 History 1.1 Drott’s Feller Buncher 1.2 Tracked Feller Buncher 1.3 Hydrostatic Feller Buncher 1.4 Three-wheeled Feller Buncher 1.5 Selective Cutting Feller Buncher 1.6 Changes in Cutting Heads 2 Features/How it Works 3 Common Manufacturers 4 Additional Photos 5 References

[edit] History

[edit] Drott’s Feller Buncher

As a long-time builder of logging equipment, Erv Drott developed the first feller-buncher in 1968 after he sold his business, J.I. Case Co., based in Wausau, Wisconsin. The machine was simple enough in concept with an excavator base and a knuckle boom-mounted felling head with a scissor-like shear attachment. It had the capacity to clear a 16-yard (15-m) wide area that is equal to about 100 trees per hour. For this very reason, the machine was viewed as a threat to logging in North America, especially on the West Coast, where trees were cut down manually with hand-held power saws. The Drott feller buncher would dramatically transform mechanized timber falling practices, eclipsing earlier harvesting machine models. As a result, a number of manufacturers would step up to develop their own versions of Drott’s machine.^[3]

[edit] Tracked Feller Buncher

One of the first companies to follow in Drott’s footsteps in the development of a feller-buncher was Koehring Waterous. Koehring already had some experience in logging equipment manufacturing with the development of a line of earlier harvesters. The company’s chief engineer John Kurelek had also attempted to build an excavator, a feat that heavy construction manufacturers John Deere and Caterpillar were also undertaking at the time. The development of an excavator proved unsuccessful. However, success soon followed in 1981 when the company introduced its first purpose-built feller buncher on a tracked chassis, the Model 620. The Model 620 was an instant hit and set the precedence in the market for tracked falling machines. Two more models were later introduced and sold under the Timberjack name after the company bought out Koehring Waterous.^[4]

[edit] Hydrostatic Feller Buncher

In 1976 a different type of feller buncher was being developed by Hydro-Ax. This version was a rubber-tired drive-to-tree feller buncher designed by Len Vizina who had worked in the woods since he was 12 years old. In 1958, he worked for Pettibone producing logging equipment such as skidders, slashers, and grapples. In 1972, he used his knowledge of the business to assist a tree-clearing company to develop a hydrostatically driven tractor with a mounted brush mower. He then got the idea of attaching logging equipment to the tractor and this lead to a version of a feller buncher that was operator-friendly and easily maneuverable. The key to the machine’s capability was attributed to hydrostatic drive.

Vizina’s machine was widely used by plantation forests in the southern U.S. where the machine could easily drive up to each tree. Hydro-Ax quickly established itself as the market leader for this version of the feller-buncher and eventually replaced the shear cutting apparatus with high-speed disc saws. By the mid-1980s other manufacturers such as John Deere and Franklin had added hydrostatic feller bunchers to their product lines.^[5]

[edit] Three-wheeled Feller Buncher

In the late 1970s, a mechanic from South Africa by the name of Irvin Bell built an early prototype of a three-wheeled feller buncher when he designed a machine to load sugar cane. At the height of South Africa’s pulp and paper industry, this machine was transformed and used for loading pulpwood. The next phase in the machine’s evolution was to hang a directional saw on it when it first showed up on the North American market. The final product was a modified version introduced to market in 1983 and developed by Bell’s son, who had assumed management of his company, and Ev Stephenson, at Union Camp. The feller buncher was affordable and became highly regarded with flat-land loggers. Its success spearheaded other companies to introduce their own tri-wheeled versions such as Franklin, Hydro-Ax, Gafner, and CTR.^[6]

[edit] Selective Cutting Feller Buncher

Pat Crawford was a third generation logger and worked as a faller in Orgeon before returning to Wisconsin to set up his own logging company on national forest land. He had an interest in equipment building and had purchased from Erv Drott, a close friend, one of Drott’s first feller bunchers. Crawford discovered Drott’s machine was not suitable for selective logging and he needed this capability to log on national forest land. The drawback of the machine was that it overhung its tracks and damaged trees still needing to grow. In 1978, he developed his first feller buncher and approached Caterpillar to manufacture the model, but Cat was not interested. Crawford was forced to raise enough capital to establish his own plant, Timbco Hydraulics. He came out with a feller buncher in 1980 that was unique. He moved the pivot point of the main boom and the anchor point of the lift cylinder behind the center of the tracked carrier to eliminate a need for a counterweight. Also, the boom’s tight configuration enabled the machine to rotate within the width of its tracks. These adjustments gave the machine the ability to selectively fall and bunch trees. Crawford eventually came out with another model that was a leveling cab and boom. While his first model operated on a two way parallel axis, his second model was leveled four ways on both a parallel and transverse axis giving the second model the capacity to work up to 50 percent more on steeper inclines. When he revealed the machine’s ability at a machine show in Spokane, Washington, it made quite a stir. Eventually his small plant in Shawano would pump out 300 machines a year for export all over the world.^[7]

[edit] Changes in Cutting Heads

One of the major developments made in feller buncher technology was the introduction of new types of power cutting heads in the mid 1980s. Many of the first models featured hydraulic shears or a chain saw head. The shears however, while a suitable apparatus in the southern U.S. were not appropriate for the Northern forestry sector, often creating shatter when cutting into frozen wood. Though manufacturers such as Hydro-Ax and Drott had attempted to address this hurdle early on, they were unable to come up with a viable solution. Research conducted by Koehring Waterous under the direction of John Kurelek and in collaboration with the Forestry Engineering Research Institute of Canada (FERIC) focused on developing a new cutting head. The result was a large circular blade saw made of carbide teeth and driven by hydraulic motors that could cut through a large tree in a matter of seconds. Though the principle idea was to use the saw for cutting into frozen northern wood, the saw eventually became the most popular cutting mechanism used on feller bunches, even in the southern U.S.^[8]

Also during the 1980s, small time manufacturers based on Vancouver Island addressed the need for heavy-duty feller bunchers as their use was rapidly spreading due to the demand of logging smaller, second growth timber. For example, Madill, a long time manufacturer of steel spars and grapple yarders developed a large feller buncher adapted for handling West Coast timber.^[9]

[edit] Features/How it Works

A feller buncher is comprised of a tracked or wheeled chassis or undercarriage, power plant, operator cab, and grabbing apparatus attached to an extended moveable arm. This apparatus clamps onto the trunk of the tree while a cutting mechanism severs the tree at the stump. The machine then lifts the tree, lowers the tree into a horizontal position, and drops the tree on a bunch of logs piled on the ground. Trees are then placed onto a special sled pulled by a tractor called a skidder for further processing. Feller bunchers are widely used in clear-cutting but have been adapted for selective logging as well. Equally, they are useful in the wholesale removal of trees from construction sites.^[10]

The machines utilize three basic mechanisms for felling and removing trees: shears, disc saws, and chain saws. The shears are like a big pair of scissors that use hydraulic power to clip the trees, mostly smaller ones. Disc saws are large, thick, circular rotary type blades that operate at a high speed. A third option is a large adaptation of a manual chain saw. These two cutting mechanisms are useful for felling larger trees. All three mechanical felling applications are similar in that the machine grabs the tree, powers the cutting mechanism through the stem, and applies force to the tree to control the direction of the tree’s fall.

These cutting mechanisms can also be attached to one of two types of carriers. A drive-to-tree machine has to maneuver to approach and cut down each tree and then drives away to drop the stem of the tree into a bunch or to cut down another tree. In a swing-to-tree machine, the cutting apparatus is attached to the end of a boom. The machine usually stays in a stationary position while cutting, swinging, and piling the tree stems into a bunch.^[11]

The use of these machines, though highly productive in logging, has not come without some serious criticism. The machines have invoked some major ecological concerns by conservationists on the impact their use has on soil compaction and soil erosion.^[12] Feller bunchers also have a reputation as being incredibly dangerous to operate. Sometimes it is hard to judge how a tree, particularly a large, heavy, tree, will react after being cut down. The weight of the tree can easily pull the entire machine over with it to the ground or branches can easily penetrate into the operator’s cab. The blade of the machine can also become lodged in a tree. Keeping the surrounding vicinity clear of workers when a feller buncher is in operation is a practice logging companies like to enforce to minimize the risk of danger; however, an operator’s safety can never be totally guaranteed.^[13]

[edit] Common Manufacturers

• Bell
• Brandt
• Caterpillar
• Franklin
• Hydro-Ax
• John Deere
• Madill
• Prentice
• Tigercat
• Timbco
• Timberjack
• Timberking

[edit] Additional Photos

[edit] References

1. ↑ Mechanical Felling. Forest Encyclopedia Network. 2008-09-25.
2. ↑ Box, Dan. “Harvesting the Forests,” The Ecologist, June 2003. pg.18
3. ↑ Druskha, Ken and Konttinen.Tracks in the Forest. Harbour Publishing: 1997. 121.
4. ↑ Druskha, Ken and Konttinen. Tracks in the Forest. Harbour Publishing: 1997. 193.
5. ↑ Druskha, Ken and Konttinen. Tracks in the Forest. Harbour Publishing: 1997. 193 - 194
6. ↑ Druskha, Ken and Konttinen. Tracks in the Forest. Harbour Publishing: 1997. 194.
7. ↑ Druskha, Ken and Konttinen. Tracks in the Forest. Harbour Publishing: 1997. 194-195.
8. ↑ Druskha, Ken and Konttinen. Tracks in the Forest. Harbour Publishing: 1997. 196
9. ↑ Druskha, Ken and Konttinen. Tracks in the Forest. Harbour Publishing: 1997. 196.
10. ↑ http://www.wisegeek.com/what-are-feller-bunchers.htm
11. ↑ Mechanical Felling. Forest Encyclopedia Network. 2008-09-25.
12. ↑ Box, Dan. “Harvesting the Forests”. The Ecologist, June 2003. pg.18
13. ↑ What Are Feller Bunchers. Wisegeek.com. 2008-09-25.