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John GARLAND, Forest Engineering Department, Oregon State University Corvallis, Oregon, UNITED STATES OF AMERICA


While the capital cost of cable logging equipment receives a great deal of attention, it may be that the human resources basis for productivity improvement is far more important than managers realize. Several activities are described for their contributions from human resources. These (described below) include: workload reduction, tools and accessories, failure avoidance, planning, training, selection, motivation and trajectories of development.

Abstract: Describes the human resources basis for productivity improvement in cable harvesting using the eight activities listed above.

Key words: cable harvesting, yarding, human resources, productivity


The cost of capital equipment for a cable yarding operation often makes the hourly pay of logging crews seem small and insignificant by comparison. For a typical Oregon operation, the yarder may cost US$450 000, the stroke delimber around US$300 000, and the loader around US$350 000. Adding the miscellaneous equipment may bring the total cost to US$1.25 million.

However, we have observed that the pace of work for the machines and perhaps the machine loadings may only be 50 percent of the machinery's potential. Furthermore, about 40–50 percent of the production cycle times may be in human-controlled work pace activities, such as hooking and unhooking logs.

Even more importantly, human decisions affect technical, economic, and institutional feasibility during planning, set-up, operations and post-harvest activities. The most important points of technical feasibility are safe work practices. Productivity and safety are not activities for trade-off with one another. I have seen many non-productive operations that were also unsafe, but I have never seen a safe operation that was also not productive in the long run.

In my judgement, as stated above, the foundation for productivity improvement in cable yarding has a major basis in the human resources activities listed below:

There would probably be more emphasis on human resource improvements if the cost/benefit or other economic analyses were more widely documented and available. How much some managers know about productivity improvement is not clear to me. I have seen some managers brag how a new machine (yarder) was making such a difference. However when I ask the crew if the line speeds were so much faster or if it would pull bigger loads, they can't say. What may have made the difference was the training, management emphasis, or crew attention that comes with installing a new yarder.

A major problem is that many of the human resource improvements suffer from the phenomenon of the “negative hypothesis”. It is impossible to show that the accident that never happened was prevented by the training on safe work practices. Let us review the human resource activities affecting productivity.

Workload reduction

Cable yarding on steep slopes is highly demanding of worker's bodies. This is evidenced by heart rate measurements and injuries to workers especially from slips and falls, plus cumulative trauma to cable loggers' knees, backs and joints. Various strategies may be considered to reduce workloads and fatigue. While I have not seen specific studies relating fatigue to serious accidents and fatalities, the injuries and fatalities from workers using the rigging to assist climbing into/out of the harvest unit provide some evidence for concern.

One strategy to reduce workloads from pulling line to reach logs is achieved by improvements to slackpulling carriages. For some small cable systems with light lines, it is possible to pull line through the carriage manually. However, pulling the sag out of a 10 mm mainline may take two people at times, depending on circumstances. Some modern slackpulling carriages actually propel the line through the carriage, and while it is not possible to “push” rope, the added thrust is welcome to a tired chokersetter (Acme Manufacturing, 2001).

When it is not possible to reduce workloads, then managing the duration of heavy work seems appropriate. By having workers rotate between chokersetting jobs and operating the yarder, some firms have been able to reduce the workloads (Kellogg and Olsen, 1984). Rest pauses are also possible to reduce workloads but are rarely utilized. Some believe the pauses between, when the turn heads to the landing and when the rigging returns, provide some rest. However, it is doubtful that the heart rates recover significantly during these short periods. Also, productive workers are using this time to set up the next turn. Some rigging crews create their own rest break by sending in several limby logs or trees to the landing, causing the extra saw work there to give them a bit of a break.

Layout for rigging cable yarding operations is sometimes made easier for long cableways through the use of helicopter to string light lines to pull heavier operating lines.

The latest prospect for workload reduction is the use of synthetic rope to replace wire rope. This rope is essentially as strong as wire rope but weighs only a tenth as much. The rope is a high molecular density polyethylene material with good resistance to chemicals and low stretch characteristics (Amsteel Blue by Samson Rope Solutions). At Oregon State University we are researching the use of this synthetic rope for static lines (guylines, straps, etc.) and possibly as running lines for cable yarding (Garland et al., 2001). Initial results showing reductions in heart rates and shorter heart rate recovery times when using synthetic versus steel-wire rope are promising. We are continuing this research over the next two years to further develop its uses. Great prospects may also lie in replacing the heavy steel rigging with synthetic materials as well.

The above strategies to reduce workloads in cable yarding are aimed at maintaining human efficiency during the portion of the production cycle when human limitations of energy and fatigue limit the operation.

Tools and accessories

Tools and accessories on the yarding operation may be used to make the human component more effective, less demanding, and safer. For the rigging crew, the use of pre-set chokers provides the opportunity to minimize the time pressure of getting logs hooked while the carriage is waiting to return to the landing. The rigging, such as sliders, ring and toggle, and “pear and toggle”, allows individual chokers to be strung into the sliding line. When safety conditions permit, two chokersetting crews may be used at different locations along the cableway. At the landing, “radio controlled chokers” that release on a radio signal provide faster, safer unhooking of logs for the landing person (Acme Manufacturing Inc., 2001).

Failure avoidance

Because of the high-line tensions that produce heavy loads on equipment, trees and anchors, cable yarding failures may be violent and catastrophic. Yarders may tip over. Trees may break or fall over. Lines and rigging may be sent flying with devastating force behind them. Accident investigations bear testimony to the forces involved. Even the small failures that are remedied before serious problems occur have a devastating effect on productivity.

Human judgement, usually gained from bad experiences, is critical to recognizing conditions that lead to failure, such as weak stump anchors, or unusual line stresses.

Technical guidance to avoid cable system failures is often available for rigging specifications, operating conditions, guying angles and so forth. While this guidance may be available in safety codes or written materials, the use of these guidelines depends on the knowledge and skill of the crew to recognize, remember and use the information during actual operations. Guidebooks are seldom seen on the operation.

Yet another approach to failure avoidance by using tension monitoring equipment depends on appropriate use and interpretation by knowledgeable crew members (Tuor Tension Monitoring Systems, 2001).


At present, it is safe to proclaim: “Humans plan while machines do not.” The ability to foresee future conditions and change current behaviour is still a trait confined to human thinking. This does not minimize the assistance provided in the planning process by computer programmes and electronically provided information and guidance.

Areal planning at various scales of harvest units over time and space provides the operations that are technically feasible, economically viable and institutionally acceptable. Planning of this nature avoids such problems as the lack of anchors from previously harvested units affecting current harvest, harvest difficulties when implementing visual management, or avoiding yarding through regenerated areas.

Unit planning is also conducted during layout using such techniques as payload analysis from “LOGGERPC” or other similar programmes (Forest Engineering Department, 2000). These planning aids, coupled with knowledgeable users, help assure yarding feasibility and system selection, e.g. use of intermediate supports or not, as determined by analysis.

Finally, the operational planning by the crew relative to yarding road changes and landing changes can dramatically affect the system productivity by reducing delays. Successful cable yarding operators use the power of planning to maintain and enhance cable yarding productivity. They recognize the human elements of planning and emphasize planned operations.


From my observation, not much about cable yarding is self-evident or obvious. Training is essential for feasible, let alone productive, cable operations. I have written on various types of training but only select two for greater review (Garland, 1987). The full list is here for reference:

For cable yarding operations, where skills accumulate with experience, it makes sense to design training to enhance the process.

Integrated job-sequence training is where an individual occupying one job learns how to do the next higher job in a sequence of job progressions. In the Northwest North America, “Hooktenders” are the working supervisors and are mostly developed from people who are termed “Rigging Slingers” (person in charge of the chokersetters). A progression is shown in Figure 1. Rigging Slingers may learn the jobs on the landing while working there and may fill in for the Hooktender under controlled circumstances to learn the necessary procedures. There are no Hooktender schools, and companies need to develop future Hooktenders from their employees.

Figure 1

Figure 1. Integrated job-sequence training (learning for the next higher job occurs while employee occupies current job)

The other training type directly related to humans is “crew productivity training.” This training emphasizes how the individual's actions combine into crew results. Earlier work on crew productivity training focused on the five “Bs” as concepts. These are:

For example, a bottleneck will occur if the loader cannot keep the landing chute clear of logs prior to when the next turn arrives. The yarder may need to wait until the loader can clear the logs and the chokersetters may also be waiting for the rigging. Various strategies can help reduce bottlenecks once they are identified. Of course, the greatest effect of crew productivity training results after individuals are well trained on their specific job performance. Improvements from training in the order of 30 percent or so are not uncommon.


When it has been possible to isolate human differences on chokersetting tasks, the performance differences may be on the order of 17 percent (Garland, 1990). These performance differences for young males are on chokersetting tasks where training is comparable and task variation itself has been reduced. Many intangible values of employees are caught up in selection preference for certain human abilities and their development of physical and mental capabilities.

Not all working populations are sufficiently large as to make selection a viable option in cable operations. In many years, logging selection is a matter of selecting from among the best of what is left from more preferable jobs.

One aspect of selection presents challenges to cable operations. Human physical abilities deteriorate over time and heavy use. By the time many cable loggers reach 40 years of age, their knees, backs, joints and other physical attributes do not allow the same levels of performance as those much younger. However, their mental growth from experience makes these older loggers valuable employees.

What some firms do is to pair the experienced worker with a younger worker who compensates for the loss of physical abilities when performing lifting, carrying, climbing and other physically demanding tasks. The firm still benefits from the older worker's experience and decision-making. This approach also relates to workload reduction with job assignments to compensate for heavy work involved during rigging anchors and trees. Some firms compensate for ageing expertise in Hooktenders (working supervisors) by assigning a younger worker to aid the experienced Hooktender with heavy manual tasks of carrying lines, blocks and rigging.


The productivity differences between motivated and unmotivated cable yarding crews can be astounding as measured by logs per day produced. It is also apparent that improperly motivated crews can make mistakes even faster than ever. The range of improvement may be in the order of a doubling of productivity for highly motivated crews. Clearly, human motivation is complex but motivating factors are identifiable. Rewards for positive performance are motivating. Punishments for negative performance are motivating.

What many managers fail to recognize are demotivating factors. These are the circumstances where positive performance is punished, e.g. concerned workers raise a safety issue and are told to mind their own business. The reverse circumstances are also demotivating when negative behaviour is rewarded (or ignored), e.g. risk-taking behaviour that seems to be productive. For demotivating behaviour, the effect on the specific worker may not be as important as the signals sent to all the workers who see management emphasis and direction. Demotivating factors may be more powerful than appropriate rewards and punishments.

While some firms may use incentives in cable yarding, the examples are not well studied or documented. A piece-rate system for yarding crews has been observed where one rate is paid per log up to a set production level and the rate per log increases after that level. Wage level guarantees may or may not be a part of the incentive system. Another approach uses a cost level target set as a parity price for a contractor, when company crews are more productive then cost savings are split between workers and the company (Olsen. 1988). Much work is needed to devise effective incentive systems for cable yarding operations.

Trajectories of development

The final basis for productivity lies in the individual's awareness of his/her trajectory of development. Everyone is on some kind of trajectory whether or not we are aware of it. The dimensions tracked for individuals over time may be net worth or some measure of significance to the firm or even an individual's assessment of their potential. What is important to individual workers is that they and management recognize a responsibility to help guide one's trajectory of development (Garland, 1999). In concrete terms, if a young cable logging crew member were to express his goals for personal advancement within the company, a wise manager would work to see the worker receive the training and experience to make the individual successful.

Likewise, each firm has a trajectory of development as measured by key dimensions, such as gross income, employees, profit, harvest levels and accidents. Cable logging firms which make their goals and directions clear may benefit from the employees adopting the goals and working to make them happen. For example, the firm may have a target of reaching 85 percent utilization for equipment (the ratio of productive machine hours over scheduled machine hours expressed as a percent). Making the trajectory and target for this dimension visible may help achieve the firm's desired outcome.

Often the trajectory of development for the firm is buried in the mind of a single company owner. Goals for the firm are non-specific or unclear. Survival of the firm may be an outcome but it is not a goal that commands the attention and adoption by employees.

In contrast, a goal to be successful along dimensions of productivity, safety, employee benefits and profit are specific and worthy of an employee's efforts. The success of the worker is the success of the firm, and the success of the firm is the success of the cable logging sector.


The foregoing discussion suggests there are a range of opportunities to consider how human resource contributions can improve productivity. By focusing on human resources the importance of productive equipment is not diminished. However, at present cable yarding equipment is not autonomous but depends on human operators. More emphasis on making the human component more effective would likely occur if detailed studies could measure the benefits and costs involved more precisely. More studies are warranted along these lines.


Acme Manufacturing, Inc. 2001. Acme carriages, pear and toggles, and Johnson radio-controlled chokers. Information from website:, dated 11 June 2001.

Forest Engineering Department. 2000. LOGGERPC. Skyline analysis program available from Forest Engineering Department, Oregon State University, Corvallis, Oregon. Windows© based program.

Garland, J. 1987. Selection, training and motivation of the logging labour force. In Proceedings of the 9th Annual Council on Forest Engineering (COFE) meeting. Mobile, Alabama, 29 September-October 2, 1986.

Garland, J.J. 1990. Assessing gains from woodsworker training: a methodology. Int. Jour. Industrial Ergonomics, (5) 1990, p. 227–242.

Garland, J.J. 1999. Trajectories of development for individuals, firms, and the forestry sector in a country. In Forest Operations of the Future Joint, FAO/ECE/ILO Committee Seminar held in Bordeaux, France, 20–24 September 1999. Afocel, Soud-Ouest, p. 329–338.

Garland, J., Sessions, J., Pilkerton, S. & Stringham, B. 2001 Synthetic rope used in logging: some potentials, Council on Forest Engineering Annual Meeting. Held 16–20 July 2001. Snowshoe, West Virginia. (In press).

Kellogg, L.D. & Olsen, E.D. 1984. Increasing the productivity of a small yarder: crew size, skidder swinging, and hot thinning. OSU Forest Research Lab Bulletin, 46. College of Forestry, Oregon State University, Corvallis, Oregon.

Olsen E.D. 1988. Logging incentive systems. OSU Forest Research Lab. Bulletin 62. College of Forestry, Oregon State University, Corvallis, Oregon.

Tuor Tension Monitoring Systems. 2001. Skyline tension monitoring system. Information from website:, June 11, 2001.

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