April Weber

April Weber

Monday, 14 March 2011 17:55

Environmental Health Issues

Forestry operations invariably affect the environment in one way or another. Some of these effects can be beneficial to the environment while others can be adverse. Obviously, it is the latter that is regarded with concern by both regulatory authorities and the public.

The Environment

When we speak of the environment, we often think of the physical and biological components of the environment: that is, the soil, the existing vegetation and wildlife and the waterways. Increasingly, the cultural, historic and amenity values associated with these more fundamental components are being considered part of the environment. Considering the impact of forest operations and management at the landscape level, not only on physical and biological objectives but also on the social values, has resulted in the evolution of concepts such as ecosystem management and forest stewardship. Therefore, this discussion of environmental health also draws on some of the social impacts.

Not All Bad News

Understandably, regulation and public concern regarding forestry throughout the world have focused on, and will continue to focus on, the negative impacts on environmental health. Despite this focus, forestry has the potential to benefit the environment. Table 1 highlights some of the potential benefits of both planting commercial tree species, and harvesting both natural and plantation forests. These benefits can be used to help establish the net effect (sum of positive and negative impacts) of forest management on environmental health. Whether such benefits accrue, and to what extent, often depends on the practices adopted (e.g., biodiversity depends on species mix, extent of tree mono-cultures and treatment of remnants of natural vegetation).

Table 1. Potential benefits to environmental health.

 Forest operations            

 Potential benefits

 Planting (afforestation)

 Increased carbon absorption (sequestration)

 Increased slope stability

 Increased recreational opportunity (amenity forests)

 Increased landscape biodiversity

 Flood control management


 Increased public access

 Reduced wildfire and disease risk

 Promotion of secessional development of natural forests


Environmental Health Issues

Despite there being major differences in forest resources, environmental regulations and concerns, as well as in forest practices throughout the world, many of the existing environmental health issues are generic across the forest industry. This overview focuses on the following issues:

  • decline in soil quality
  • soil erosion
  • changes in water quality and quantity (including sedimentation)
  • impacts on biodiversity
  • adverse public perception of forestry
  • discharge of chemicals (oil and pesticides) into the environment.


The degrees to which these general issues are a concern in a particular area will be largely dependent on the sensitivity of the forested area, and the nature of the water resources and water users downstream or offsite from the forest.

Activities within forested areas can affect other areas. These impacts can be direct, such as visual impacts, or they may be indirect, such as the effects of increased suspended sediment on marine farming activities. Therefore, it is important to recognize the pathways linking different parts of the environment. For example: skidder logging --- streamside soils --- stream water quality --- downstream recreational water users.

Decline in soil quality

Forest management can affect soil quality (Powers et al. 1990; FAO/ECE/ILO 1989, 1994). Where forests have been planted to rehabilitate degraded soils, such as eroded soils or mining overburden, this net impact may be an increase in quality by improving soil fertility and structural development. Conversely, forest activities on high-quality soil have the potential to reduce soil quality. Activities causing nutrient depletion, organic matter loss and structural loss through compaction are particularly important.

Soil nutrients are used by vegetation during the growing cycle. Some of these nutrients may be recycled back to the soil through litter fall, death or by residual logging waste. Where all the vegetative material is removed during harvest (i.e., whole tree harvest) these nutrients are removed from the onsite nutrient cycle. With successive growing and harvesting cycles, the store of available nutrients within the soil may decline to levels where growth rates and tree nutrient status cannot be sustained.

Burning of logging wastes has in the past been a preferred means of promoting regeneration or preparing a site for planting. However, research has shown that intensely hot burns can result in the loss of soil nutrients (carbon, nitrogen, sulphur and some phosphorus, potassium and calcium). The consequences of depleting the store of soil nutrients can be reduced tree growth and changes in species composition. The practice of replacing lost nutrients through inorganic fertilizers may address some of the nutrient depletion. However, this will not mitigate the effects of the loss of organic matter which is an important medium for soil fauna.

The use of heavy machinery for harvesting and preparation for planting can result in soil compaction. Compaction can cause reduced air and water movement in a soil and increase the strength of the soil to the extent that tree roots can no longer penetrate. Consequently, compaction of forest soils can reduce tree survival and growth and increase rainfall runoff and soil erosion. Importantly, without cultivation, compaction of subsoils may persist for 20 to 30 years after logging. Increasingly, logging methods that reduce the areas and degree of compaction are being used to reduce decline in soil quality. The codes of forest practices adopted in a growing number of countries and discussed in the article “Rules, legislation, regulations and codes of forest practices” in this chapter provide guidance on such methods.

Soil erosion

Soil erosion is a major concern to all land users, as it can result in irreversible loss of productive soils, adversely impact visual and amenity values, and may impact water quality (Brown 1985). Forests can protect soils from erosion by:

  • intercepting rainfall
  • regulating ground water levels
  • increasing slope stability because of root growth
  • protecting soil from wind and frost action.


However, when an area of forest is harvested, the level of soil protection is significantly reduced, increasing the potential for soil erosion.

It is recognized worldwide that forest operations associated with the following activities are major contributors to increased soil erosion during the forest management cycle:

  • road work
  • earthworks
  • harvesting
  • burning
  • cultivation.


Road work activities, particularly in steep terrain where cut and fill construction is used, produce significant areas of loose unconsolidated soil material that are exposed to rainfall and runoff. If drainage control on roads and tracks is not maintained, they can channel rainfall runoff, increasing the potential for soil erosion on lower slopes and on the road edges.

Harvesting of forest trees can increase soil erosion in four main ways:

  • exposing surface soils to rainfall
  • reducing stand water usage, thereby increasing soil water contents and groundwater levels
  • causing gradual decline in slope stability as the root system decomposes
  • disturbance of soils during wood extraction.


Burning and cultivation are two techniques often used to prepare a site for regeneration or planting. These practices can increase the potential for surface erosion by exposing surface soil to the erosive effects of rainfall.

The degree of increased soil erosion, by either surface erosion or mass wasting, will depend on many factors including the size of the area logged, the slope angles, the strength of slope materials and the time since the harvesting occurred. Large clear cuts (i.e., total removal of almost all trees) can be a cause of severe erosion.

The potential for soil erosion can be very high during the first year after harvest relative to before road construction and harvesting. As the re-established or regenerating crop begins to grow, the risk of increased soil erosion decreases as water interception (protection of surface soils) and transpiration increase. Usually, the potential for increased erosion declines to pre-harvest levels once the forest canopy masks the ground surface (canopy closure).

Forest managers aim to reduce the period of vulnerability or the area of a catchment vulnerable at any one time. Staging the harvesting to spread harvesting over several catchments and reducing the size of individual harvest areas are two alternatives.

Changes in water quality and quantity

The quality of water discharged from undisturbed forest catchments is often very high, relative to agricultural and horticultural catchments. Certain forest activities can reduce the quality of water discharged by increasing nutrient and sediment contents, increasing water temperatures and decreasing dissolved oxygen levels.

Increased nutrient concentrations and exports from forest areas that have been burnt, undergone soil disturbance (scarification) or had fertilizer applied, can adversely effect water weed growth and cause pollution of downstream waters. In particular, nitrogen and phosphorus are important because of their association with toxic algae growth. Similarly, increased sediment input into waterways can adversely affect freshwater and marine life, flooding potential and water utilization for drinking or industrial uses.

The removal of streamside vegetation and the introduction of green and woody material into waterways during thinning or harvesting operations can adversely affect the aquatic ecosystem by increasing water temperatures and levels of dissolved oxygen in the water, respectively.

Forestry can also have an impact on the seasonal volume of water leaving a forest catchment (water yield) and peak discharges during storm events. Planting of trees (afforestation) in catchments previously under a pastoral farming regime can reduce water yields. This issue can be of particular importance where the water resource below an afforested area is utilized for irrigation.

Conversely harvesting within an existing forest can increase water yields because of the loss of water transpiration and interception, increasing the potential for flooding and erosion in the waterways. The size of a catchment and the proportion harvested at any one time will influence the extent of any water yield increase. Where only small proportions of a catchment are harvested, such as patch cuts, the effects on yield may be minimal.

Impacts on biodiversity

Biodiversity of plants and animals within forest areas has become an important issue for the forest industry worldwide. Diversity is a complex concept, not being confined to different plant and animal species alone. Biodiversity also refers to functional diversity (the role of a particular species in the ecosystem), structural diversity (layering within the forest canopy) and genetic diversity (Kimmins 1992). Forest operations have the potential to impact species diversity as well as the structural and functional diversity.

Identifying what is the optimum mix of species, ages, structures and functions is subjective. There is a general belief that a low level of species and structural diversity predisposes a forest to increased risk of disturbance with a pathogen or pest attack. To some extent this may be true; however, individual species in a mixed natural forest may suffer exclusively from a particular pest. A low level of biodiversity does not imply that a low level of diversity is an unnatural and unwanted outcome of forest management. For instance, many mixed species natural forests which are naturally subject to wildfire and pest attack go through stages of low species and structural diversity.

Adverse public perception of forestry

The public perception and acceptance of forest practice are two increasingly important issues for the forest industry. Many forest areas provide considerable recreational and amenity value to the resident and travelling public. The public often associates pleasurable outdoors experiences with mature managed and natural forested landscapes. Through insensitive harvesting, particularly large clearcuts, the forest industry has the potential to dramatically modify the landscape, the effects of which are often evident for many years. This contrasts with other land uses such as agriculture or horticulture, where the cycles of change are less evident.

Part of the negative public response to such activities stems from a poor understanding of forest management regimes, practices and outcomes. This clearly puts the onus on the forest industry to educate the public while at the same time modifying their own practices to increase public acceptance. Large clearcuts and the retention of logging residues (branch materials and standing dead wood) are two issues often causing public reaction because of the association of these practices with a perceived decline in ecosystem sustainability. However, this association may not be based in fact, as what is valued in terms of visual quality does not imply benefit for the environment. Retention of residues, although looking ugly, does provide habitat and food for animal life, and provides for some cycling of nutrients and organic matter.

Oil in the environment

Oil can be discharged in the forest environment through the dumping of machine oil and filters, the use of oil to control dust on unpaved roads and from chain-saws. Because of concerns about contamination of soil and water by mineral oil, oil dumping and its application on roads are becoming unacceptable practices.

However, the use of mineral oil to lubricate chain-saw bars is still common practice in much of the world. About 2 litres of oil are used by a single chain-saw per day, which adds up to considerable volumes of oil over a year. For example, it has been estimated that chain-saw oil usage was approximately 8 to 11.5 million litres/year in Germany, approximately 4 million litres/year in Sweden and approximately 2 million litres/year in New Zealand.

Mineral oil has been linked with skin disorders (Lejhancova 1968) and respiratory problems (Skyberg et al. 1992) in workers in contact with the oil. Furthermore, the discharge of mineral oil into the environment can result in soil and water contamination. Skoupy and Ulrich (1994) quantified the fate of chain-saw bar lubricant and found that between 50 and 85% was incorporated in the sawdust, 3 to 15% remained on trees, less than 33% was discharged onto the forest floor and 0.5% sprayed onto the operator.

Concerns primarily for the environment have led to biodegradable oils being compulsory in Swedish and German forests. Based on rapeseed or synthetic-based oils, these oils are more friendly to the environmentally and worker, and can also out-perform mineral-based lubricants by offering better chain life and reduced oil and fuel consumption.

Use of herbicides and insecticides

Herbicides (chemicals that kill plants) are employed by the forest industry to reduce weed competition for water, light and nutrients with young planted or regenerating trees. Often herbicides offer a cost-effective alternative to mechanical or manual weed control.

Despite there being a general mistrust of herbicides, possibly as a result of the use of Agent Orange during the Vietnam war, there have been no real documented adverse impacts on soils, wildlife and humans from herbicide use in forestry (Kimmins 1992). Some studies have found decreases in mammal numbers following herbicide treatment. However, by also studying the effects of manual or mechanical weed control, it has been shown that these decreases are coincidental with the loss of vegetation rather than the herbicide itself. Herbicides sprayed near waterways can potentially enter and be transported in the water, although herbicide concentrations are usually low and short term as dilution takes effect (Brown 1985).

Prior to the 1960s, the use of insecticides (chemicals that kill insects) by the agricultural, horticultural and public health sectors was widespread, with lesser amounts being used in forestry. Perhaps one of the more commonly used insecticides used during this time was DDT. Public reaction to health issues has largely curbed the indiscriminate use of insecticides, leading to the development of alternative practices. Since the 1970s, there have been moves towards the use of insect disease organisms, the introduction of insect pests and predators and modification of silvicultural regimes to reduce the risk of insect attack.



Monday, 14 March 2011 17:53

Living Conditions

Forestry operations, especially in developing countries, tend to be temporary and seasonal. In general, this work takes place far from urban centres, and workers must travel long distances every day or remain for several days or weeks in camps near the worksites. When workers commute from their homes every day, working conditions depend in large measure on their wages, the size of their family, their level of education and the access they have to health services. These variables, which are related to the level of development a nation has achieved and to the organization of the family group, are key to guaranteeing that basic necessities will be covered. These basic necessities include adequate nourishment, which is especially important given the intensity of the effort required of forestry workers. In many regions even commuting workers will still need protection against adverse weather conditions during breaks, particularly against rain and cold. Mobile shelters are available that are specially designed and equipped for forestry. If such forestry shelters are not provided, those used on construction sites can serve the purpose too. The situation in the camps is different, since their quality depends on the facilities provided by the company in terms of infrastructure and maintenance. The discussion which follows therefore refers to living conditions in forestry camps in so far as housing, leisure and nourishment are concerned.

Camp Infrastructure

Camps can be defined as temporary homes for forestry workers when they operate in remote or hard-to-reach locations. To fulfil their purpose, the camps should provide at least minimal levels of sanitation and comfort. It is therefore important to ask: How do different people interpret what these minimal levels should be? The concept is subjective, but it is possible to assert that, in the case of a camp, the minimal conditions required are that the infrastructure provide facilities and basic services that are consistent with human dignity, where each worker can partake with others on the crew without having to significantly alter his or her personal habits or beliefs.

One question that needs to be addressed when planning a forestry camp is the time that the camp will remain in a particular location. Since normally tasks must be shifted from one place to the other, fixed camps, while easier to set up and maintain, are not the solution that is usually required. In general, mobile structures are the most practical, and they should be easy to take down and move from one location to the next. This presents a complex problem, because even well-built modules deteriorate easily as they are moved. Conditions at mobile camps, therefore, tend to be very primitive.

In terms of facilities, a camp should offer an adequate supply of water, enough dormitories, a kitchen, bathrooms and recreation facilities. The size of each site will depend on the number of people who will be using it. In addition there should be separate stores for food, fuel, tools and materials.

Dormitories should allow workers to maintain their privacy. Since this is generally not possible in a camp, the number of people should not exceed six in each dormitory. This number has been arrived at through experience, since it has been found that a collapsible structure can accommodate six workers comfortably, allowing enough room for lockers where they can keep their personal belongings. In sharp contrast to this example, a dormitory that is crowded and dirty is absolutely inadequate for human use. An adequate dormitory is sanitary, with a clean floor, good ventilation and a minimal effort to create a comfortable atmosphere (e.g., with curtains and bedspreads of the same colour).

The kitchen, for its part, constitutes one of the most critical facilities in a camp. The first requirement is that the individuals in charge of the kitchen be skilled in sanitation and food handling. They should be licensed by an authorized authority and be supervised regularly. The kitchen should be easy to clean and should have adequate space for food storage. If food is stocked weekly or biweekly the kitchen should have a refrigerator to keep perishable food. It may be inconvenient and time-consuming for workers to return to camp for lunch: sanitary arrangements should be provided for packing lunches for workers to carry with them or to be delivered to them.

With regards to recreation facilities, mess halls are commonly used for this purpose. If workers are at their tasks all day and the only place to unwind is the eating quarters, these rooms should have enough of an infrastructure to allow workers to feel comfortable and recuperate physically and mentally from their workday. There should be adequate ventilation and, if the season requires, heating. Eating tables should not be for more than six people and should be lined with an easy to clean surface. If the dining-room is also used for recreation it should have, when possible, a television or a radio that can let workers stay in touch with the rest of the world. It is also advisable to provide some table games like checkers, cards and dominoes. Since among forestry workers there is an important contingent of young workers, it is not a bad idea to set up an area where they can play sports.

One aspect that is extremely important is the quality of sanitary facilities, showers and facilities for workers to wash and dry their belongings. It is important to keep in mind that faeces and waste in general are one of the most common avenues for the transmission of disease. It is therefore better to obtain water from a deep well than from a shallow one. If electric pumps can be installed, well-water may be raised into tanks that can then supply the camp. If for any reason it is not possible to erect sanitary services of this kind, chemical latrines should be installed. In any case, the elimination of human and other waste should be done carefully, making especially sure that they are not discharged in areas close to where food is kept or where drinking water is obtained.


Nutrition is a basic necessity for the maintenance of life and for the health of all human beings. Food provides not only nutrients but the energy required to carry out all activities in daily life. In the case of forestry workers, the caloric content of foods consumed is especially important because most of the harvesting, handling and forest protection activities demand great physical exertion (see the article “Physical load” in this chapter for data on energy consumption in forest work). Forestry workers need, therefore, more nourishment than people who do less demanding work. When a worker does not consume enough energy to offset daily energy expenditures, at first he or she will burn the reserves accumulated in body fat, losing weight. However, this can be done for only a limited time. It has been observed that, in the medium term, those workers who do not obtain in their diet the energy equivalent to their daily expenditures will limit their activity and lower their output. As a consequence, if they are paid by piece rate, their income also decreases.

Before analysing just how much energy a worker must consume as part of his or her diet, it bears mentioning that modern forestry work relies on increasingly sophisticated technology, where human energy is replaced by that of machinery. In those situations, operators run the risk of consuming more energy than they require, accumulating the excess as fat and risking obesity. In modern society, obesity is a malady that affects many people, but it is unusual in forestry workers where traditional methods are employed. According to studies carried out in Chile, it is becoming more common among machine operators. Obesity diminishes the quality of life because it is associated with a lower physical aptitude, predisposing those who suffer from it to accidents and to illnesses such as cardiovascular disease and more joint and muscle lesions.

For this reason all forestry workers, whether their daily activity is heavy or sedentary, should have access to a well-balanced diet that provides them with adequate amounts of energy. The key is to educate them so that they can regulate their food needs themselves. Unfortunately, this is a fairly difficult problem to solve; the tendency observed in studies carried out in Chile is for workers to consume all the food provided by the company and, in general, to still find their diet insufficient even though their weight variations indicate the opposite. The solution therefore is to educate the workers so that they learn to eat according to their energy requirements.

If workers are well informed about the problems created by eating too much, camps should offer diets keeping in mind the workers with the highest energy expenditures. The intake and expenditure of human energy is commonly expressed in kilojoules. However, the more widely known unit is the kilocalorie. The amount of energy required by a forestry worker when the job demands intense physical exertion, as in the case of a chain-saw operator or a worker using an axe, can reach 5,000 calories a day or even more. However, to expend those high amounts of energy, a worker must have a very good physical aptitude and reach the end of the workday without undue fatigue. Studies carried out in Chile have resulted in recommendations of an average of 4,000 calories provided daily, in the form of three basic meals at breakfast, lunch and dinnertime. This allows for the possibility of snacking at mid-morning and mid-afternoon so that additional amounts of energy can be provided. Studies over periods of more than a year have shown that, with a system like the one described, workers tend to maintain their body weight and increase their output and their incomes when pay is tied to their output.

A good diet must be balanced and provide, in addition to energy, essential nutrients for the maintenance of life and good health. Among other elements a diet should provide adequate amounts of carbohydrates, proteins, fats, minerals and vitamins. The tendency in developing countries is for groups that have low incomes to consume fewer proteins and fats and higher amounts of carbohydrates. The lack of the first two elements is due to a low consumption of foods of animal origin. In addition, a lack of certain vitamins and minerals has been observed due to a low consumption of foods of animal origin, fruits and vegetables. To summarize, the diet should be varied to balance the intake of essential nutrients. The most convenient option is to seek the help of specialized dieticians who know about the demands of heavy work. These professionals can develop diets that are reasonably cost efficient and that take into account the tastes, the traditions and the beliefs of the consumers and provide the amounts of energy required by forestry workers for their daily labour.

A very important element is a supply of liquid of good quality—not contaminated and in sufficient quantity. In manual and chain-saw work with high temperatures, a worker needs approximately 1 litre of liquid per hour. Dehydration drastically reduces working capacity and ability to concentrate, thereby increasing the risk of accidents. Therefore water, tea or other suitable drinks need to be available at the worksite as well as in the camp.

Consumption of alcohol and drugs should be strictly forbidden. Cigarette smoking, which is a fire hazard as well as a health hazard, should only be allowed in restricted areas and never in dormitories, recreation areas, dining halls and worksites.


This article has dealt with some of the general measures that can improve the living conditions and the diet of forestry camps. But while these two aspects are fundamental, they are not the only ones. It is also important to design the work in an ergonomically appropriate way because accidents, occupational injuries and the general fatigue that result from these activities have an impact on output and consequently on incomes. This last aspect of forestry work is of vital importance if workers and their families are to enjoy a better quality of life.



Monday, 14 March 2011 17:51

Skills and Training

Skills, Training and Exposure

In many industries, attention to safety in the design of equipment, workplaces and work methods can go a long way toward reducing occupational safety and health hazards. In the forestry industry, exposure to risks is largely determined by the technical knowledge, skill and experience of the individual worker and the supervisor, and their commitment to a joint effort in planning and performing the work. Training, therefore, is a crucial determinant of health and safety in forestry.

Studies in different countries and for different jobs in forestry all concur that three groups of workers have a disproportionately high accident frequency: the unskilled, often seasonal, workers; the young; and new entrants. In Switzerland, fully 73% of the accidents affect workers with less than one year in forestry; likewise, three-quarters of the accident victims had no or only rudimentary training (Wettman 1992).

Untrained workers also tend to have a much higher workload and higher risk of back injuries because of poor technique (see “Tree planting” in this chapter for an example). If training is critically important both from a safety and a productivity point of view in normal operations, it is absolutely indispensable in high-risk tasks like salvaging windblown timber or firefighting. No personnel should be allowed to participate in such activities unless they have been especially trained.

Training Forest Workers

On-the-job training is still very common in forestry. It is usually very ineffective, because it is a euphemism for imitation or simply trial and error. Any training needs to be based on clearly established objectives and on well-prepared instructors. For new chain-saw operators, for example, a two-week course followed by systematic coaching at the workplace is the bare minimum.

Fortunately, there has been a trend towards longer and well-structured training in industrialized countries, at least for directly employed workers and most new entrants. Various European countries have 2-to-3-year apprenticeships for forest workers. The structure of training systems is described and contacts to schools are listed in FAO/ECE/ILO 1996b. Even in these countries there is, however, a widening gap between the above and problem groups such as self-employed, contractors and their workers, and farmers working in their own forest. Pilot schemes to provide training for these groups have demonstrated that they can be profitable investments, as their cost is more than offset by savings resulting from reductions in accident frequency and severity. In spite of its demonstrated benefits and of some encouraging examples, like the Fiji Logging School, forest worker training is still virtually non-existent in most tropical and subtropical countries.

Forest worker training has to be based on the practical needs of the industry and the trainee. It has to be hands-on, imparting practical skill rather than merely theoretical knowledge. It can be provided through a variety of mechanisms. Schools or training centres have been used widely in Europe with excellent results. They do, however, carry a high fixed cost, need a fairly high annual enrolment to be cost-effective, and are often far from the workplace. In many countries mobile training has, therefore, been preferred. In its simplest form, specially prepared instructors travel to workplaces and offer courses according to programmes that may be standard or modular and adaptable to local needs. Skilled workers with some further training have been used very effectively as part-time instructors. Where demand for training is higher, specially equipped trucks or trailers are used as mobile classrooms and workshops. Designs and sample equipment lists for such units are available (Moos and Kvitzau 1988). For some target groups, such as contractors or farmers, mobile training may be the only way to reach them.

Minimum Competence Standards and Certification

In all countries, minimum standards of skill should be defined for all major jobs, at least in forest harvesting, the most hazardous operation. A very suitable approach to make sure minimum standards are defined and actually met in the industry is skill certification based on testing workers in short theoretical and practical exams. Most schemes place emphasis on standardized tests of workers’ skill and knowledge, rather than on whether these have been acquired through training or long experience. Various certification schemes have been introduced since the mid-1980s. In many cases certification has been promoted by workers’ compensation funds or safety and health directorates, but there have also been initiatives by large forest owners and industry. Standard tests are available for chain-saw and skidder operators (NPTC and SSTS 1992, 1993; Ministry of Skills Development 1989). Experience shows that the tests are transferable without or with only minor amendment. In 1995 for example the ILO and the Zimbabwe Forestry Commission successfully introduced the chain-saw test developed in an ILO logging training project in Fiji.



Safety in the forestry sector depends on matching individuals’ work capacities to the conditions under which they perform their tasks. The closer the mental and physical requirements of the work approach the workers’ capacities (which, in turn, vary with age, experience and health status), the less likely safety is to be sacrificed in an attempt to satisfy production goals. When individual capacities and working conditions are in a precarious balance, decreased individual and collective safety is inevitable.

As figure 1 illustrates, there are three sources of safety hazards related to working conditions: the physical environment (climate, lighting, terrain, types of trees), deficient safety laws and standards (inadequate content or application) and inappropriate work organization (technical and human).

Figure 1.  Determinants of safety hazards in forestry work.


The technical and human organization of work encompasses potentially hazardous factors that are both distinct and tightly linked: distinct, because they refer to two intrinsically different resources (i.e., humans and machines); linked, because they interact and complement each other during the execution of work activities, and because their interaction allows production goals to be reached safely.

This article details how flaws in the components of work organization listed in figure 1 can compromise safety. It should be noted that measures to protect safety and health cannot be retro-fitted onto an existing work method, machine or organization. They need to be part of the design and planning.

Technical Work Organization

The term technical work organization refers to operational considerations of forestry work, including the type of cut, the choice of machinery and production equipment, equipment design, maintenance practices, size and composition of the work crew(s) and the time allotted in the production schedule.

Type of cut

There are two main types of cut used in forestry operations, distinguished by the technology used to fell and debranch trees: conventional cutting, which relies on mechanical saws, and mechanical cutting, which relies on machines operated from control cabins and equipped with articulated booms. In both cases, skidders, especially chain- or claw-propelled ones, are the usual means of transporting felled trees along the side of the road or waterways. Conventional cutting is the more widespread and the more dangerous of the two.

Mechanization of cutting is known to considerably reduce the frequency of accidents. This is most apparent for accidents occurring during production operations, and is due to the replacement of mechanical saws by machines operated from remote control cabins which isolate operators from hazards. At the same time, however, mechanization appears to increase the risk of accidents during machine maintenance and repair. This effect is due to both technological and human factors. Technological factors include machine deficiencies (see below) and the often improvised, if not frankly ludicrous, conditions under which maintenance and repair operations are performed. Human factors include the existence of production bonuses, which often result in low priority being given to maintenance and repair operations and the tendency to perform them hastily.

Machine design

There are no design codes for forestry machinery, and comprehensive maintenance manuals are rare. Machines such as fellers, debranchers and skidders are often a mixture of disparate components (e.g., booms, cabins, base machines), some of which are designed for use in other sectors. For these reasons, machinery used in forestry operations may be poorly suited to some environmental conditions, especially those related to the state of the forest and the terrain, and to continuous operation. Finally, machine repair is frequently necessary but very difficult to perform.

Machine and equipment maintenance

Maintenance practices in the forest are usually corrective rather than preventive. Various working conditions—such as production pressures, the absence of strict maintenance guidelines and schedules, the lack of appropriate maintenance and repair sites (garages, shelters), the harsh conditions under which these operations are performed, and the lack of adequate tools—may explain this situation. In addition, financial constraints may operate on one-person operations or sites operated by subcontractors.

Human Work Organization

The term human work organization refers to the way in which collective or individual human efforts are administered and organized, and to training policies designed to satisfy production requirements.


Supervision of forestry work is not easy, due to the constant relocation of worksites and the geographic dispersion of workers over multiple worksites. Production is controlled through indirect strategies, of which production bonuses and the maintenance of precarious employment status are probably the most insidious. This type of work organization does not favour good safety management, since it is easier to transmit information concerning safety guidelines and regulations than it is to ensure their application and evaluate their practical value and the extent to which they are understood. Managers and supervisors need to be clear that they have primary responsibility for safety. As can be seen in figure 2 the worker controls very few of the elements that determine safety performance.

Figure 2.  Human factors have an impact on safety in forest work.


Type of contract

Regardless of the type of cut, work contracts are almost always negotiated individually, and are often of fixed or seasonal duration. This precarious work situation is likely to lead to a low priority being accorded to personal safety, since it is difficult to promote occupational safety in the absence of minimal guarantees of employment. In concrete terms, fellers or operators may find it difficult to work safely if this compromises the production goals upon which their employment depends. Longer-term contracts of guaranteed minimum volumes per year stabilize the workforce and increase safety.


Subcontracting the responsibility (and costs) for selected production activities to owner-operators is becoming more widespread in the forestry sector, as a result of mechanization and its corollary, work specialization (i.e., using a specific machine for tasks such as felling, pruning, felling-pruning and skidding).

Subcontracting may affect safety in several ways. In the first place, it should be recognized that subcontracting does not reduce safety hazards as such, but merely transfers them from the entrepreneur to the subcontractor. Secondly, subcontracting may also exacerbate certain hazards, since it stimulates production rather than safety-oriented behaviour. Subcontractors have in fact been observed to neglect some safety precautions, especially those related to preventive maintenance, training of new hires, the provision of personal protective equipment (PPE) and the promotion of its use, and the observance of safety rules. Finally, the responsibility for safety maintenance and management at worksites where subcontracting is practised is a judicial grey zone. It may even be difficult to determine the responsibility for declaring accidents to be work related. Work contracts should make compliance with safety regulations binding, include sanctions against offences, and assign responsibility for supervision.

Division of labour

The division of labour on forestry sites is often rigid and encourages specialization rather than flexibility. Task rotation is possible with conventional cutting, but is fundamentally dependent on team dynamics. Mechanized cutting, on the other hand, encourages specialization, although the technology itself (i.e., machine specialization) is not the sole cause of this phenomenon. Specialization is also encouraged by organizational factors (one operator per machine, shift work), geographic dispersion (remoteness of machines and cutting zones) and the fact that operators commonly own their machines.

Isolation and communication problems resulting from this division of labour may have serious consequences for safety, especially when they hamper the efficient circulation of information concerning imminent dangers or the occurrence of an incident or accident.

Work capacities of machines and workers need to be carefully matched and crews composed accordingly, to avoid overloading elements in the production chain. Shift schedules can be designed that maximize the use of expensive machines but give enough rest and variety of tasks to the operators.

Production-based pay scales

Forestry workers are frequently paid on a piece-work basis, which is to say that their salary is determined by their output (number of felled, pruned or transported trees, or some other index of productivity), not by its duration. For example, the rate which machine owners are paid for the use of their machines is proportional to their productivity. This type of pay scale, while not directly controlling workers, is notorious for stimulating production.

Production-based pay scales may encourage high work rates and the recourse to unsafe work practices during production and short-cuts in maintenance and repair operations. Practices like these persist because they save time, even though they ignore established safety guidelines and the risks involved. The greater the production incentive, the more safety is compromised. Workers paid on the basis of production have been observed to suffer more accidents, as well as different types of accidents, than hourly-paid workers performing the same type of work. Piece rates and prices for contracts need to be adequate for safe execution and acceptable working hours. (For a recent empirical study in Germany, see Kastenholz 1996.)

Work schedules

In the forest, long daily and weekly work schedules are the norm, since worksites and cutting zones are remote, work is seasonal, and the often difficult climatic and environmental factors encourage workers to work as long as possible. Other factors encouraging longer work schedules include production incentives (pay scales, subcontracting) and the possibility of using certain machines on a continuous basis (i.e., without stopping at night).

Long work schedules often result in decreased vigilance and a loss of sensory acuity, both of which may have effects on individual and collective safety. These problems are aggravated by the rarity and brevity of rest periods. Planned breaks and maximum working hours should be observed. Ergonomic research demonstrates that output can actually be increased that way.


There can be no doubt that forestry work is physically and mentally demanding. The skill level required is continually increasing, as a result of technological advances and the growing complexity of machines. Prior and onsite training of forestry workers are therefore very important. Training programmes should be based on clearly defined objectives and reflect the actual work to be performed. The more the training programmes’ content corresponds to actual working conditions and the greater the integration of safety and production concerns, the more useful the programmes will be, both individually and collectively. Effective training programmes not only reduce material losses and production delays but also avoid additional safety hazards. For guidance on training, see “Skills and training” in this chapter.


The safety of forestry work is determined by factors related to work organization, and technical and human aspects of work organization may disrupt the equilibrium between production goals and safety. The influence of each individual factor on occupational safety will of course vary from setting to setting, but their combined effect will always be significant. Furthermore, their interaction will be the prime determinant of the degree to which prevention is possible.

It should also be noted that technological developments do not, in and of themselves, eliminate all hazards. Design criteria for machines should take into account their safe operation, maintenance and repair. Finally, it appears that some increasingly widespread management practices, especially subcontracting, may exacerbate rather than reduce safety hazards.



Monday, 14 March 2011 17:34

Personal Protective Equipment

Forestry work is one of those occupations where personal protective equipment (PPE) is always needed. Mechanization has decreased the number of workers using hand-held chain-saws, but the remaining tasks are often in difficult places where the big machines cannot reach.

The efficiency and chain speed of the hand-held chain-saws have increased, while the protection given by protective clothing and footwear has decreased. The higher requirement for the protection has made the equipment heavy. Especially in summertime in Nordic countries, and all around the year in other countries, the protective devices add an extra load to the heavy work of forest workers. This article focuses on chain-saw operators, but protection is needed in most forestry work. Table 1 provides an overview of what should normally be required.

Table 1.  Personal protective equipment appropriate for forestry operations.


Operations PPE1
Planting Manual Mechanized
Safety boots or shoes Safety boots or shoes, close-fit clothing, ear muffs2
Weeding/cleaning Smooth-edged tools Hand-saw Chain-saw
Safety boots or shoes, gloves, goggles Safety boots or shoes, gloves Safety boots or shoes,safety trousers, close-fit clothing, gloves,4 safety helmet, goggles, visor (mesh), ear muffs
Brush saw: with metal blade with nylon filament
Safety boots or shoes,3 safety trousers, close-fit clothing, gloves,4 safety helmet, goggles, visor (mesh), ear muffs Safety boots or shoes, safety trousers, gloves, goggles, ear muffs
Rotating knife/flail Safety boots or shoes, close-fit clothing, gloves, ear muffs2
Pesticide application To comply with the specifications for the particular substance and application technique
Pruning5 Hand tools
Safety boots or shoes, gloves, safety helmet, 6 goggles, ear muffs
Felling7 Hand tools Chain-saw
Safety boots or shoes, close-fit clothing, gloves,8 safety helmet Safety boots or shoes, safety trousers, close-fit clothing, gloves,4 safety helment, visor (mesh), ear muffs
Mechanized Safety boots or shoes, close-fit clothing, safety helmet, ear muffs
Debarking Manual Mechanized
Safety boots or shoes, gloves Safety boots or shoes, close-fit clothing, gloves, goggles, ear muffs2
Splitting Manual Mechanized
Safety boots or shoes, gloves, goggles Safety boots or shoes, close-fit clothing, gloves, goggles, ear muffs
Extraction Manual, chute and animal Mechanized -skidder -forewarder -cable crane -heliocopter
Safety boots or shoes, gloves, safety helmet9
Safety boots or shoes, close-fit clothing, gloves,10 safety helmet, ear muffs2 Safety boots or shoes, close-fit clothing, safety helmet, ear muffs2 Safety boots or shoes, close-fit clothing, gloves,10 safety helmet, ear muffs2 Safety boots or shoes, close-fit clothing,11 gloves,10 safety helmet, goggles, ear muffs
Stacking/loading Safety boots or shoes, close-fit clothing, gloves, safety helmet, ear muffs2
Chipping Safety boots or shoes, close-fit clothing, gloves, safety helmet, visor (mesh), ear muffs2
Tree climbing: using a chain-saw not using a chain-saw
Safety boots or shoes,3 safety trousers, close-fit clothing, gloves,4 safety helmet,13 goggles, ear muffs Safety boots or shoes, safety helmet

1 Safety boots or shoes should include integrated steel toes for medium or heavy loads.   Safety trousers should incorporate clogging material; in hot climates/weather   chain-saw leggings or chaps may be used. Safety trousers and chaps contain fibres   that are inflammable and can melt; they should not be worn during firefighting.   Ear plugs and ear valves are generally not suitable for forestry because of risk of infection.

2 When noise level at work position exceeds 85 dBA.

3 Chain-saw boots must have protective guarding at front vamp and instep.

4 Cut-resistant material must be incorporated.

5 If pruning involves tree climbing above 3 m, a fall-restricting device should be used.   PPE must be used when falling branches are likely to cause injury.

6 When pruning to a height exceeding 2.5 m.

7 Felling includes debranching and crosscutting.

8 When using a hand-saw.

9 When extracting near unstable trees or branchwood.

10 Only if manipulating logs; gloves with heavy-duty palm if handling wire choker rope or tether line.

11 Highly visible colours should be used.

12 Helmet must have a chin strap.

13 Climbing helmets are preferable; if they are not available, safety helmets with chin straps   may be used.

Source: ILO 1997.



Protection Mechanism and Efficiency of Personal Protective Devices

Protective clothing

Protective clothing against cuts protects by three different main mechanisms. In most cases the trousers and gloves contain a safety padding made of multilayer cloth having fibres with high tensile strength. When the moving chain touches the fibres, they are pulled out and will resist the movement of the chain. Second, these padding materials can go around the drive sprocket and the groove of the blade and increase the friction of the chain against the blade so much that the chain will stop. Third, the material can also be made such that the chain glides on the surface and cannot easily penetrate it.

Different work tasks require different protective coverage. For normal forest work the protective padding covers only the front part of the trousers and the back of safety gloves. Special tasks (e.g., gardening or tree surgery) often require a larger area of protective coverage. The protective paddings cover the legs totally, including the back side. If the saw is held above the head, protection of the upper body may be needed.

It must always be remembered that all PPE gives only limited protection, and correct and careful working methods must be used. The new hand-held chain-saws are so effective that the chain can easily go through the best protective material when the chain speed is high or the force of the chain against the protective material is great. Cut-proof protective paddings made of the best materials known at present would be so thick that they could not be used in heavy forest work. The compromise between protection efficiency and comfort is based on field experiments. It has been unavoidable that the protection level has been reduced to be able to increase the comfort of the clothing.

Protective footwear

Protective footwear made of rubber resists against cuts by the chain-saw quite well. The most frequent type of cut comes from contact of the chain with the toe area of the footwear. The safety footwear must have a cut-resistant lining on the front and metallic toe cups; this protects against these cuts very well. In higher temperatures the use of rubber boots is uncomfortable, and leather boots or ankle-high shoes should be used. These shoes too must be equipped with metallic toe cups. The protection is normally considerably lower than that of the rubber boots, and extra care should be taken when using leather boots or shoes. The working methods must be so planned that the possibility of chain contact with the feet is minimized.

Good fit and construction of the outer sole is essential to avoid slipping and falling accidents, which are very common. In areas where the ground may be covered by ice and snow or where workers walk on slippery logs, boots which can be equipped with spikes are preferred.

Protective helmet

Protective helmets provide protection against falling branches and trees. They also give protection against the chain-saw if a kick-back occurs. The helmet should be as light as possible to minimize neck strain. The headband must be correctly adjusted to make the helmet sit firmly on the head. The headbands of most helmets are so designed that vertical adjustment is possible as well. It is important to have the helmet sitting low on the brow so its weight does not cause too much discomfort when working in face-down posture. In cold weather it is necessary to use a textile or fur cap under the helmet. Special caps designed to be used with the helmet should be used. The cap can lower the protection efficiency of the helmet by wrong positioning of the helmet. The protection efficiency of hearing protectors can go to near zero when the cups of the hearing protectors are placed outside the cap. Forestry helmets have built-in devices to attach a visor and earmuffs for hearing protection. The cups of the hearing protectors should be placed directly against the head by insertion of the cups through slits in the cap.

In hot weather, helmets should have ventilation holes. The holes have to be part of the design of the helmet. Under no circumstances should holes be drilled into the helmet, as this may greatly reduce its strength.

Face and eye protection

The face protector or shield is normally attached to the helmet and is most commonly made of a mesh material. The plastic sheets easily get dirty after a relatively short working time. Cleaning is also difficult because the plastics resist solvents poorly. The mesh reduces the light coming to the eyes of the worker, and reflections on the surface of the threads can make seeing difficult. Sealed goggles worn under face protectors mist easily, and distortion of vision is often too high. Metal masks with a black coating and rectangular rather than round openings are preferable.

Hearing protectors

Hearing protectors are efficient only if the cups are placed firmly and tightly against the head. Therefore hearing protectors must be used carefully. Any space between the head and the sealing rings of the cups will decrease the efficiency markedly. For example, the side-arms of spectacles can cause this. The sealing ring shall be inspected often and must be changed when damaged.

Selection of Personal Protective Equipment

Before starting work in a new area, the possible risks should be evaluated. The working tools, methods, environment, the skills of the workers and so on should be evaluated, and all technical and organizational measures should be planned. If the risks cannot be eliminated by those methods, PPE can be used to improve the protection. PPE can never be used as the only preventive method. It must be seen as a complementary means only. The saw must have a chain brake, the worker must be trained and so on.

On the basis of this risk analysis, the requirements for personal protective devices must be defined. Environmental factors should be taken into account in order to minimize the load cased by the equipment. The hazard caused by the saw must be evaluated and the protection area and efficiency of clothing defined. If the workers are not professionals, the protection area and level should be higher, but this extra loading must be taken into account when the work periods are planned. After the requirements for PPE are defined according to the risks and tasks, the proper equipment is selected from among devices that have been approved. The workers should have the privilege of trying different models and sizes to select the one that best suits them. Improperly selected clothing can cause abnormal postures and movements, and thus can increase accident and health hazard risks. Figure 1 illustrates the selection of equipment.

Figure 1.  Bodily location of injuries and personal protective equipment recommended for forest work, the Netherlands, 1989.


Determination of the Conditions of Use

All workers should be efficiently instructed and trained in the use of PPE. The protection mechanism must be described so that the workers themselves can inspect and evaluate the condition of the equipment daily. The consequences of non-use must be made clear. Proper cleaning and repair instructions must be given.

The protective equipment used in forestry work may constitute a relatively great extra burden to the worker. This must be taken into account when planning the working times and rest periods.

Often the use of PPE gives a false sense of safety. The supervisors must make sure that risk taking is not increasing and that the workers know well the limits of the protection efficiency.

Care and Maintenance

Improper methods used for maintenance and repair can destroy the protection efficiency of the equipment.

The shell of the helmet must be cleaned by weak detergent solutions. Resins cannot be removed efficiently without the use of solvents, but the use of solvents should be avoided because the shell can be damaged. The instructions of the manufacturer must be followed and the helmet discarded if it cannot be cleaned. Some materials are more resistant against the effects of solvents, and those should be selected for forest work use.

Also other environmental factors affect the materials used in a helmet. Plastic materials are sensitive to ultraviolet (UV) radiation of the sun, which makes the shell more rigid, especially at low temperatures; this ageing weakens the helmet, and it will not protect against impacts as planned. The ageing is difficult to see, but small hairline cracks and the loss of gloss can be signs of ageing. Also, when gently twisted, the shell may make cracking noises. The helmets should be carefully visually inspected at least every six months.

If the chain has been in contact with the trousers, the protection efficiency can be much reduced or disappear totally. If the safety padding fibres are drawn out, the trousers should be discarded and new ones should be used. If only the outer material is damaged it can be repaired carefully without making any stitches through the safety padding. The protection efficiency of safety trousers is commonly based on the strong fibres, and if those are fixed tightly during repair they will not provide protection as planned.

Washing must be done according to the instructions given by the manufacturer. It has been shown that wrong washing methods can destroy protection efficiency. The clothing of the forest worker is difficult to clean, and products should be selected which withstand the hard washing methods needed.

How the Approved Protective Equipment is Marked

The design and quality of manufacture of PPE must meet high standards. In the European Economic area, personal protective devices must be tested before they are placed on the market. The basic health and safety requirements for PPE are described in a directive. To clarify those requirements European harmonized standards have been drafted. The standards are voluntary, but devices designed to meet the requirements in the appropriate standards are deemed to meet the requirements of the directive. The International Standards Organization (ISO) and the European Committee for Standardization (CEN) are working on these standards together according to the Vienna Agreement. So there will be technically identical EN and ISO standards.

Accredited test stations are testing the devices and issuing a certificate if they meet the requirements. After that the manufacturer can mark the product with CE-marking, which shows that the conformity assessment has been carried out. In other countries the procedure is similar and the products are marked with the national approval mark.

An essential part of the product is the leaflet giving the user information about its proper use, the degree of protection it can provide and instructions for its cleaning, washing and repair.



In a high-risk occupation like forestry, relevant and job-specific safety regulations are a critical element of any strategy to reduce the high frequencies of accidents and health problems. To develop such regulation and to obtain compliance is unfortunately much more difficult in forestry than in many other occupations. Occupational safety legislation and existing general regulations are often not specific for forestry. Moreover, they are often difficult to apply in the highly variable outdoor context of forestry, because they were typically conceived with factory-type workplaces in mind.

This article outlines the route from general legislation to forestry-specific regulations and makes some suggestions for contributions that the various actors in the forestry sector may make to the improvement of compliance with regulations. It concludes with a brief presentation of the concept of codes of forest practices, which holds considerable promise as a form of regulation or self-regulation.

The Law Outlines the Principles

Safety legislation usually merely lays out some basic principles, such as:

  • The employer is primarily responsible for the safety of employees and must take the necessary protective measures.
  • Employees must be involved in this.
  • Employees, in turn, are obliged to support the employer’s efforts.
  • Laws are enforced through the labour inspectorate, the health service or an analogous body.


What the General Regulations Specify

Regulations on prevention of accidents and occupational diseases often specify a number of points, such as:

  • the duties of employers and employees
  • the consultation of doctors and other occupational safety specialists
  • the safety regulations for buildings and other construction, for technical equipment and devices, and on the working environment and the work organization.


The regulations also contain instructions on:

  • organization of workplace safety
  • implementing the provisions on workplace safety
  • occupational medical care
  • financing workplace safety.


As the legislation has evolved over time, there are often laws for other areas and sectors that also contain regulations applicable to workplace safety in forestry. In Switzerland, for example, these include the labour code, the law on explosives, the law on poisons and traffic legislation. It would be advantageous to users if all these provisions and related regulations were collected into a single law.

Safety Regulations for Forestry: As Concrete as Possible and Nevertheless Flexible

In most cases, these laws and regulations are too abstract for daily, on-the-job use. They do not correspond to the hazards and risks involved in using machines, vehicles and work materials in the various industries and plants. This is particularly true for a sector with such varied and atypical working conditions as forestry. For this reason, specific safety regulations are worked out by sectoral commissions for the individual industries, their specific jobs, or equipment and devices. In general, this proceeds consciously or unconsciously as follows:

First, the dangers that can arise in an activity or a system are analysed. For example, cuts into the leg are a frequent injury among chain-saw operators.

Second, protection goals that are based on the dangers identified and which describe “what should not happen” are enunciated. For example: “Appropriate measures should be taken to prevent the chain-saw operator from injuring his or her leg”.

Only in the third step are solutions or measures sought that, in accordance with the state of technology, reduce or eliminate the dangers. In the above-mentioned example, cut-protected trousers are one of the appropriate measures. The state of technology for this item can be defined by requiring that trousers correspond to European Norms (EN) 381-5, Protective clothing for users of hand-operated chain-saws, Part 5: Regulations for leg protection.

This procedure offers the following advantages:

  • Protective goals are based on concrete hazards. The safety requirements are therefore practice-oriented.
  • Safety regulations in the form of protective goals allow for greater flexibility in the choice and development of solutions than the prescription of concrete measures. Specific measures can also be adapted continuously to advances in the state of technology.
  • When new hazards appear, safety regulations can be supplemented in a targeted manner.


Establishing bi- or tripartite sectoral commissions that involve the interested employer and employee organizations has proven an effective way of improving the acceptance and application of safety regulations in practice.

Content of Safety Rules

When certain jobs or types of equipment have been analysed for their hazards and protective goals derived, measures in the areas of technology, organization and personnel (TOP) can be formulated.

Technical questions

The state of technology for part of the forestry equipment and devices, such as power saws, brush cutters, leg protection for power saw operators and so on, is set in international norms, as discussed elsewhere in this chapter. Over the long term, the EN and the norms of the International Organization for Standardization (ISO) should be unified. Adoption of these norms by the individual countries will contribute to the uniform protection of the employee in the industry. Proof from the seller or manufacturer that a piece of equipment complies with these standards guarantees to the buyer that the equipment corresponds to the state of technology. In the numerous cases where no international standards exist, national minimum requirements need to be defined by groups of experts.

In addition to the state of technology, the following issues, among other things, are important:

  • availability of the necessary equipment and materials on the job
  • reliable condition of the equipment and materials
  • maintenance and repair.


Forestry operations often leave much to be desired in these respects.

Organizational questions

Conditions must be established in the enterprise and at the workplace so that the individual jobs can be carried out safely. In order for this to happen, the following issues must be addressed:

  • tasks, authority and responsibilities of all participants clearly defined
  • a wage system that promotes safety
  • working hours and breaks adapted to the difficulty of the work
  • work procedures
  • work planning and organization
  • first aid and alarms
  • where workers have to live in camps, minimum requirements defined for dormitories, sanitation, nutrition, transport and recreation.


Personnel questions

Personnel questions can be divided into:

Training and continuing education. In some countries this includes employees of forestry companies, for example, those who work with power saws are obliged to attend appropriate training and continuing education courses.

Guidance, welfare and support of the employee. Examples include showing new employees how the job is done and supervising the employees. Practice shows that the state of workplace safety in an enterprise depends in large measure on whether and how the management maintains discipline and carries out its supervisory responsibilities.

Doing the job

Most safety regulations contain rules of behaviour that the employee is supposed to abide by in doing the job. In forestry work these rules relate primarily to critical operations such as:

  • felling and working with trees
  • extraction, storing and transporting wood
  • working with wind-felled trees
  • climbing trees and working in treetops.


In addition to international standards and national regulations that have proved effective in several countries, the International Labour Organization (ILO) Code of Practice Safety and Health in Forestry Work provides examples and guidance for the design and formulation of national or company-level regulations (ILO 1969, 1997, 1998).

Safety regulations have to be reviewed and constantly adapted to changing circumstances or supplemented to cover new technology or work methods. A suitable accident reporting and investigation system can be of great help toward this end. Unfortunately, few countries are making use of this possibility. The ILO (1991) provides some successful examples. Even rather simple systems can provide good pointers. (For further information see Strehlke 1989.) The causes of accidents in forestry are often complex. Without a correct and full understanding, preventive measures and safety regulations often miss the point. A good example is the frequent but often erroneous identification of “unsafe behaviour” as the apparent cause. In accident investigation, the emphasis should as much as possible be on understanding the causes of accidents, rather than on establishing the responsibility of individuals. The “tree of causes” method is too onerous to be used routinely, but has given good results in complicated cases and as a means of raising safety awareness and of improving communication in enterprises. (For a report on the Swiss experience see Pellet 1995.)

Promoting Compliance

Safety regulations remain a dead letter unless all stakeholders in the forestry sector play their part in implementation. Jokulioma and Tapola (1993) give a description of such cooperation in Finland, which has produced excellent results. For information, education and training on safety, including for groups that are difficult to reach like contractors and forest farmers, the contractor and forest owner associations play a critical role.

Safety regulations need to be made available to users in accessible form. A good practice is the publishing in a pocket-size format of illustrated concise extracts relevant to particular jobs such as chain-saw operation or cable cranes. In many countries migrant workers account for a significant percentage of the forestry workforce. Regulations and guides need to be available in their respective languages. Forestry equipment manufacturers should also be required to include in the owner’s manual comprehensive information and directions on all aspects of the maintenance and safe use of the equipment.

The cooperation of workers and employers is of course particularly important. This is true at the sectoral level, but even more so at the enterprise level. Examples for successful and very cost effective cooperation are given by the ILO (1991). The generally unsatisfactory safety situation in forestry is often aggravated further where the work is carried out by contractors. In such cases, the contracts offered by the commissioning party, forest owner or industry should always include a clause requiring compliance with safety requirements as well as sanctions in cases of breach of regulations. The regulations themselves should be an annex to the contract.

In some countries, general legislation provides for a joint or subsidiary responsibility and liability of the commissioning party—in this case a forest owner or company—with the contractor. Such a provision can be very helpful in keeping irresponsible contractors out and favouring the development of a qualified service sector.

A more specific measure in the same direction is the accreditation of contractors through government authorities or workers’ compensation administrators. In some countries contractors have to demonstrate that they are sufficiently equipped, economically independent and technically competent to carry out forestry work. Contractor associations could conceivably play a similar role, but voluntary schemes have not been very successful.

Labour inspection in forestry is a very difficult task, because of the dispersed, temporary worksites, often in faraway, inaccessible places. A strategy motivating the actors to adopt safe practices is more promising than isolated policing. In countries where large forestry companies or forest owners predominate, self-inspection of contractors by such companies, monitored by the labour inspectorate or workers’ compensation administration, is one way of increasing coverage. Direct labour inspection should be focused both in terms of issues and geography, to make optimum use of staff and transport. As labour inspectors are often non-foresters, inspection should best be based on thematic checklists (“chain-saws”, “camps” and so on), which inspectors can use after a 1- or 2-day training. A video on labour inspection in forestry is available from the ILO.

One of the biggest challenges is to integrate safety regulations into routine procedures. Where forestry-specific regulations exist as a separate body of rules, they are often perceived by supervisors and operators as an additional constraint on top of technical, logistic and other factors. As a result, safety considerations tend to be ignored. The remainder of this article describes one possibility of overcoming this obstacle.

Codes of Forest Practice

In contrast to general occupational safety and health regulations, codes of practice are sets of rules, prescriptions or recommendations that are forestry-specific and practice-oriented and ideally cover all aspects of an operation. They include safety and health considerations. Codes vary greatly in scope and coverage. Some are very concise while others are elaborate and go into considerable detail. They may cover all types of forest operations or be limited to the ones considered most critical, such as forest harvesting.

Codes of practice can be a very interesting complement to general or forestry-specific safety regulations. Over the last decade, codes have been adopted or are being developed in a growing number of countries. Examples include Australia, Fiji, New Zealand, South Africa and numerous states in the United States. At the time of writing, work was in progress or planned in various other countries, including Chile, Indonesia, Malaysia and Zimbabwe.

There are also two international codes of practice that are designed as guidelines. The FAO Model Code of Forest Harvesting Practice (1996) covers all aspects of general forest harvesting practices. The ILO Code of Practice Safety and Health in Forestry Work, first published in 1969 and to be published in a completely revised form in 1998 (available in 1997 as a working paper (ILO 1997)), deals exclusively with occupational safety and health.

The driving force behind new codes has been environmental rather than safety concerns. There is, however, a growing recognition that in forestry, operational efficiency, environmental protection and safety are inseparable. They result from the same planning, work methods and practices. Directional felling to reduce impact on the remaining stand or regeneration, and rules for extraction in steep terrain, are good examples. Some codes, like the FAO and the Fiji Codes, make this link explicit and simultaneously address productivity, environmental protection and work safety. Ideally, codes should not have separate chapters on safety, but should have occupational safety and health built into their provisions.

Codes should be based on the safest work methods and technology available, require safety to be considered in planning, establish required safety features for equipment, list required personal protective equipment and contain rules on safe work practices. Where applicable, regulations about camps, nutrition and worker transport should also be included. Safety considerations should also be reflected in rules about supervision and training.

Codes can be voluntary and be adopted as mandatory by groups of companies or the forestry sector of a country as a whole. They can also be legally binding. In all cases they may be enforceable through legal or other complaints procedures.

Many codes are drawn up by the forestry sector itself, which ensures practicability and relevance, and enhances commitment to comply. In the case of Chile, a tripartite committee has been established to develop the code. In Fiji the code was originally designed with strong industry involvement and then made binding by the Ministry of Forests.

The characteristics described above and the experience with existing codes make them a most interesting tool to promote safety in forestry, and offer the possibility of very effective cooperation between safety officers, worker’s compensation administrators, labour inspectors and forestry practitioners.



People active outdoors, especially in agriculture and forestry, are exposed to health hazards from animals, plants, bacteria, viruses and so on to a greater degree than is the rest of the population.

Plants and Wood

Most common are allergic reactions to plants and wood products (wood, bark components, sawdust), especially pollen. Injuries can result from processing (e.g., from thorns, spines, bark) and from secondary infections, which cannot always be excluded and can lead to further complications. Appropriate protective clothing is therefore especially important.

A comprehensive description of the toxicity of plants and wood products and their components is not possible. Knowledge of a particular area can be acquired only through practical experience—not only from books. Possible safety measures must derive from knowledge of the specific area.

Large Mammals

Using horses, oxen, buffalo, elephants and so on as work animals can result in unforeseen dangerous situations, which may lead to injuries with serious consequences. Diseases transmittable from these animals to humans also pose an important danger.

Infections and Diseases Transmitted by Animals

These constitute the most significant biological hazard. Their nature and incidence varies strongly from region to region. A complete overview is therefore not possible. Table 1 contains a selection of infections common in forestry.

Table 1.  Selection of infections common in forestry.








Entamoeba histolytica

Person-to-person, ingestion with food (water, fruits, vegetables); often asymptomatic carriers

Tropics and temperate zone

Frequent complications of the digestive tract

Personal hygiene; chemoprophylaxis and immunization not possible.

Therapy: chemotherapy

Dengue fever


Aedes mosquito bite

Tropics, subtropics, Caribbean

Sickness results in immunity for one year or longer, not lethal

Control and elimination of carrier mosquitoes, mosquito nets.

Therapy: symptomatic

Early summer meningo-encephalitis


Linked to the presence of the ixodes ricinus tick, vector-free transmission known in individual cases (e.g., milk)

Natural reservoirs confined to certain regions, endemic areas mostly known

Complications with later damages possible

Active and passive immunization possible.

Therapy: symptomatic


Erysipelotrix rhusiopathiae

Deep wounds among persons who handle fish or animal tissue

Ubiquitous, especially infects swine

Generally spontaneous cure after 2-3 weeks, bacteremia possible (septic arthritis, affected cardiac valve)

Protective clothing

Therapy: antibiotics


Wuchereria bancrofti, Brugia malayi

From animal to humans, but also from some types of mosquitoes

Tropics and subtropics

Highly varied

Personal hygiene, mosquito control.

Therapy: medication possible

Fox tapeworm

Echinococcus multilocularis

Wild animals, esp. foxes, less commonly also house pets (cats, dogs)

Knowledge of endemic areas necessary

Mostly affects liver

No consumption of raw wild fruits; dampen fur when handling dead foxes; gloves, mouth protection

Therapy: clinical treatment

Gaseous gangrene

Various clostridia

At the onset of infection, anaerobic milieu with low redox potential and necrotic tissue required (e.g., open crushed soft parts)

Ubiquitous, in soil, in intestines of humans and animals

Highly lethal, fatal without treatment (1-3 days)

No known specific antitoxin to date, gaseous gangrene serum controversial

Therapy: clinical treatment

Japanese B encephalitis


From mosquitoes (Culex spp.); person-to-person; mammal-to-person

Endemic in China, India, Japan, Korea and neighbouring countries

Mortality to 30%; partial cure to 80%

Mosquito prevention, active immunization possible;

Therapy: symptomatic


Various leptospira

Urine of infected wild and house animals (mice, rats, field rabbits, foxes, dogs), skin injuries, mucous membrane

Endemic worldwide areas

From asymptomatic to multi-organ infestation

Appropriate protective clothing when around infected animals, immunization not possible

Therapy: penicillin, tetracycline

Lyme disease

Borrelia burgdorferi

Ixodes ricinus tick, other insects also suspected

Europe, North America, Australia, Japan, China

Numerous forms of sickness, complicating organ infection possible

Personal protective measures before tick infectation, immunization not possible

Therapy: antibiotics

Meningitis, meningo-encephalitis

Bacteria (meningo-, pneumo-staphylococci and others)

Mostly airborne infection

Meningococci, meningitis epidemic, otherwise ubiquitous

Less than 10% mortality with early diagnosis and specific treatment

Personal hygiene, isolate infected persons

Therapy: antibiotics


Viruses (Poliomyelitis, Coxsackie, Echo, Arbo, Herpes and Varicella viruses)

Mucous and airborne infection (airways, connective tissue, injured skin), mice are source of infection in high percentage of cases

Ubiquitous incidence

High mortality (70%) with herpes infection

Personal hygiene; mouse prevention

Therapy: symptomatic, among varicella effective specific treatment possible



Mostly systemic infections

Ubiquitous incidence

Uncertain prognosis

Therapy: antibiotics (protracted treatment)


Mycobacteria (see tuberculosis)






Leptospira (see leptospirosis)






Various plasmodia (tropica, vivax, ovale, falciparum, malariae)

mosquitoes (Anopheles species)

Subtropical and tropical regions

30% mortality with M. tropica

Chemoprophylaxis possible, not absolutely certain, mosquito nets, repellents, clothing

Therapy: medication





Various filaria

Flies, water

West and Central Africa, India, Pakistan, Guinea, Middle East

Highly varied

Fly control, personal hygiene

Therapy: surgery, medication, or combined


Clamydia psittaci

Birds, especially parrot varieties and doves


Fatal cases have been described

Eliminate pathogen reservoir, immunization not possible

Therapy: tetracycline

Papatasii fever


Mosquitoes (Phlebotomus papatasii)

Endemic and epidemic in Mediterranean countries, South and East Asia, East Africa, Central and South America

Mostly favourable, often long convalescence, sickness leaves far-reaching immunity

Insect control

Therapy: symptomatic



Bite from infected wild or house animals (saliva highly infectious), airborne infection described

Many countries of the world, widely varying frequency

Highly lethal

Active (including after exposure) and passive immunization possible

Therapy: clinical treatment

Recurrent fever


Ticks, head and body lice, rodents

America, Africa, Asia, Europe

Extensive fever; up to 5% mortality if untreated

Personal hygiene

Therapy: medication (e.g., tetracycline)


Clostridium tetani

Parenteral, deep unclean wounds, introduction of foreign bodies

Ubiquitous, especially common in tropical zones

Highly lethal

Active and passive immunization possible

Therapy: clinical treatment


Trichuris trichiura

Ingested from eggs that were incubated 2-3 weeks in the ground

Tropics, subtropics, seldom in the United States

Only serious infections display symptoms

Personal hygiene

Therapy: medication possible

Tsutsugamushi fever


(R. orientalis)

Associated with mites (animal reservoir: rats, mice, marsupials); infection from working on plantations and in the bush; sleeping outdoors especially dangerous

Far East,

Pacific region, Australia

Serious course; mortality close to zero with timely treatment

Rodent and mite control, chemoprophylaxis controversial

Therapy: timely antibiotics


Various myco-bacteria (e.g., M. bovis, avium balnei)

Inhaling infected droplets, contaminated milk, contact with infected wild animals (e.g., mountain goats, deer, badgers, rabbits, fish), wounds, mucous membranes


Still high mortality, depending on organ infected

Active immunization possible, chemoprophylaxis disputed

Therapy: clinical treatment, isolation, medication


Francisella tularensis

Digestive tract wounds, contaminated water, rodents, contact with wild rabbits, ticks, arthropods, birds; germs can also enter through uninjured skin


Varied forms of sickness; first sickness leads to immunity; mortality with treatment 0%, without treatment appr. 6%

Caution around wild animals in endemic areas, disinfect water

Therapy: antibiotics

Yellow fever


Bite from forest mosquitoes, which are infected from wild primates

Central Africa, South and Central America

Up to 10% mortality

Active immunization


Poisonous Snakes

Poisonous snakebites are always medical emergencies. They require correct diagnosis and immediate treatment. Identifying the snake is of decisive importance. Due to the wide range of varieties and territorial particularities, the knowledge necessary for this can be acquired only locally, and for this reason cannot be described in general. Blocking veins and local incisions (only by experienced people) are not undisputed as a first-aid measure. A prompt dose of a specific antidote is necessary. Attention must also be paid to the possibility of a life-threatening allergic general reaction to the antidote. Injured persons should be transported lying down. Do not administer alcohol or morphine.


Few poisons have been researched to date. An attempt should absolutely be made to identify the spider (of which knowledge can be acquired only locally). Actually, there are no valid general first-aid measures (possibly administer available antiserums). In addition, what was said about poisonous snakes applies analogously.

Bees, Wasps, Hornets, Ants

Insect poisons have very different effects, depending on the locale. Removing the stinger from the skin (and being careful not to introduce more poison during handling) and local cooling are recommended first-aid measures. The most-feared complication is a life-threatening general allergic reaction, which can be provoked by an insect sting. People allergic to insect poisons should, therefore, carry adrenalin and an injectable antihistamine with them.


After injury, a dose of antidote should absolutely be given. Local knowledge of first aid is necessary.



Monday, 14 March 2011 17:21

Chemical Hazards

Fuel and Oils for Portable Machines

Portable forestry machines such as chain-saws, brush saws and mobile machines are sources of exhaust emissions of gasoline in logging operations. Gasoline contains mainly aromatic (including up to 5% benzene in some countries) and aliphatic hydrocarbons, additives and some impurities. During the cold season gasoline contains more lightweight and easily evaporating hydrocarbons than during warm season. Additives are organic lead compounds, alcohols and ethers which are used to increase the octane number of gasoline. In many cases, lead has been totally replaced by ethers and alcohols.

The portable machines used in forestry are powered by two-stroke engines, where lubricating oil is mixed with gasoline. Lubrication oils as well as chain oils are mineral oils, synthetic oils or vegetable oils. The exposure to gasoline and lubrication and chain oil may occur during mixing fuel and filling as well as during logging. Fuels are also a fire hazard, of course, and require careful storage and handling.

Oil aerosols may create health hazards such as irritation of the upper respiratory tract and eyes, as well as skin problems. The exposure of lumberjacks to oil aerosols was studied during manual logging. Both mineral and vegetable oils were investigated. The exposure of forestry workers to oil aerosols was on the average 0.3 mg/m3 for mineral oil and even less for vegetable oil.

The mechanization of forestry work is increasing rapidly. The machines in logging operations use large amounts of fuel oil, lubricants and hydraulic oils in their engines and hydraulic systems. During maintenance and repair operations, the hands of machine operators are exposed to lubricants, hydraulic oils and fuel oils, which may cause irritant dermatitis. Mineral oils with short-chain hydrocarbons (C14–C21) are the most irritant. To avoid irritation, the skin must be protected from oil contact by protective gloves and good personal hygiene.


Exhaust Gases

The main component of chain-saw exhaust gases is unburned gasoline. Usually about 30% of the gasoline consumed by a chain-saw engine is emitted unburned. The main components of exhaust emission are hydrocarbons which are typical constituents of gasoline. Aromatic hydrocarbons, particularly toluene, are usually identified among them, but even benzene is found. Some of the exhaust gases are formed during combustion, and the main toxic product among them is carbon monoxide. As a result of combustion there are also aldehydes, mainly formaldehyde, and nitrogen oxides.

The exposure of workers to exhaust gases from chain-saws has been studied in Sweden. Operator exposure to chain-saw exhaust was evaluated under various logging situations. Measurements revealed no difference in average levels of exposure when logging in the presence or in the absence of snow. The felling operation, however, results in short-term high exposure levels, especially when the operation is performed while there is deep snow on the ground. This is judged to be the main cause of the discomfort experienced by loggers. Average exposure levels for loggers engaged only in felling were twice as high as those for cutters who also perform delimbing, bucking and manual skidding of timber. The latter operations involved considerably lower exposure. Typical average levels of exposure are as follows: hydrocarbons, 20 mg/m3; benzene, 0.6 mg/m3; formaldehyde, 0.1 mg/m3; carbon monoxide, 20 mg/m3.

These values are clearly below the 8-hour occupational exposure limit values in industrialized countries. However, loggers often complain about irritation of the upper respiratory tract and eyes, headache, nausea and fatigue, which can be at least partly explained by these exposure levels.

Pesticides and Herbicides

Pesticides are used in forests and forest nurseries to control fungi, insects and rodents. The overall quantities used are typically small when compared with agricultural use. In forests herbicides are used to control hardwood brush, weeds and grass in young softwood sapling stands. Phenoxy herbicides, glyphosate or triazines are used for this purpose. For occasional needs, insecticides, mainly organophosphorus compounds, organochlorine compounds or synthetic pyredroids may also be used. In forest nurseries dithiocarbamates are used regularly to protect softwood seedlings against fungus of pines. An overview of chemicals used in Europe and North America in the 1980s is provided in table 1. Many countries have taken measures to find alternatives to pesticides or to restrict their use. For more detail on the chemistry, chemical symptoms of intoxication and treatment see the chemicals section of this Encyclopaedia.

Table 1.  Examples of chemicals used in forestry in Europe and North America in the 1980s.




Benomyl, Borax, Carbendazim, Chlorothalonil, Dicropropene, Endosulphaani, Gamma-HCH, Mancozeb, Maneb, Methyl bromide, Metiram, Thiuram, Zineb

Game control

Polyvinyl acetate

Game damage control


Game repellents

Fish oil, tall oil


Allyl alcohol, Cyanazin, Dachtal, Dalapon, Dicamba, Dichlobenil, Diuron, Fosamine, Glyphosate, Hexazinone, MCPA, MCPB, Mecoprop (MCPP), MSMA, Oxyfluorten, Paraquat, Phenoxy herbicides (e.g., 2,4,5-T*, 2,4-D), Picloram, Pronoamide, Simazine, Sulphur, TCA, Terbuthiuron, Terbuthylazine, Trichlopyr, Trifluralin


Azinphos, Bacillus thuringiens, Bendiocarpanate, Carbaryl, Cypermethrin, Deltamethrin, Diflubenzuron, Ethylene dibromide, Fenitrothion, Fenvalerate, Lindane, Lindane+promecarb, Malathion, Parathion, Parathionmethyl, Pyrethrin, Permethrin, Propoxur, Propyzamide, Tetrachlorphinos, Trichlorfon


Captan, Chlorpyrifos, Diazinon, Metalyxyl, Napropamide, Sethoxydim, Traiadimefon, Sodium cyanide (rabbits)


Aluminium phosphide, Strychnine, Warfarin, Zinc phosphide, Ziram

Soil sterilant


Stump protection


Fuels and oils

Mineral oils, synthetic oils, vegetable oils, gasoline, diesel oil

Other chemicals

Fertilizers (e.g., urea), solvents (e.g., glycol ethers, long-chain alcohols), Desmetryn

* Restricted in some countries.

Source: Adapted from Patosaari 1987.

A wide variety of techniques are used for the application of pesticides to their intended target in forests and forestry nurseries. Common methods are aerial spraying, application from tractor-driven equipment, knapsack spraying, ULV spraying and the use of sprayers connected to brush saws.

The risk of exposure is similar to that in other pesticide applications. To avoid exposure to pesticides, forestry workers should use personal protective equipment (PPE) (e.g., cap, coveralls, boots and gloves). If toxic pesticides are applied, a respiratory device should also be worn during applications. Effective PPE often leads to heat build-up and excessive sweating. Applications should be planned for the coolest hours of the day and when it is not too windy. It is also important to wash all spills immediately with water and to avoid smoking and eating during spray operations.

The symptoms caused by excessive exposure to pesticides vary greatly depending on the compound used for application, but most often occupational exposure to pesticides will cause skin disorders. (For a more detailed discussion of pesticides used in forestry in Europe and northern America see FAO/ECE/ILO 1991.)


Other chemicals commonly used in forestry work are fertilizers and colourants used for timber marking. Timber marking is done either with a marking hammer or a spray bottle. The colourants contain glycol ethers, alcohols and other organic solvents, but the exposure level during the work is probably low. The fertilizers used in forestry have low toxicity, and the use of them is seldom a problem in respect of occupational hygiene.



Monday, 14 March 2011 17:10

Psychosocial Factors

As is apparent from articles in this chapter, physical risks in forestry work are rather well documented. By contrast, comparatively little research has focused on psychological and social factors (Slappendel et al. 1993). In a forestry context such factors include: job satisfaction and security; the mental workload; susceptibility and response to stress; coping with perceived risks; work pressure, overtime and fatigue; need to endure adverse environmental conditions; social isolation in work camps with separation from families; work organization; and teamwork.

The health and safety situation in forest work depends on the wide range of factors described in this chapter: stand and terrain conditions; infrastructure; climate; technology; work methods; work organization; economic situation; contracting arrangements; worker accommodation; and education and training. These factors are known to interact and may actually compound to create higher risk or safer working environments (see “Working conditions and safety in forestry work” in this chapter).

These factors also interact with social and psychological ones, in that they influence the status of forest work, the recruitment base and the pool of skills and abilities that becomes available to the sector. In an unfavourable situation the circle of problems depicted in figure 1 can be the result. This situation is unfortunately rather common in developing countries and in segments of the forestry workforce in industrialized countries, in particular among migrant workers.

Figure 1. The circle of problems that may be encountered in forest work.


The social and psychological profile of the forestry workforce and the selection process that leads to it are likely to play a major role in determining the impact of stress and risk situations. They have probably not received enough attention in forestry. Traditionally, forest workers have come from rural areas and have considered work in the forest as much a way of life as an occupation. It has often been the independent, outdoors nature of the work that attracted them. Modern forest operations often no longer fit such expectations. Even for those whose personal profiles matched the demands of the job rather well when they started, the rapid technological and structural change in forestry work since the early 1980s has created major difficulties. Workers unable to adapt to mechanization and an existence as an independent contractor are often marginalized. To reduce the incidence of such mismatches, the Laboratory of Ergonomics at the University of Concepción in Chile has developed a strategy                                                                                                                         for forest worker selection, taking into account the needs of the                                                                                                                         industry, social aspects and psychological criteria.

Moreover, many new entrants still come ill-prepared to the job. On-the-job training, which is often no more than trial and error, is still common. Even where training systems are well developed, the majority of workers may have no formal training. In Finland, for example, forest machine operators have been trained for almost 30 years and a total of over 2,500 graduated. Nonetheless, in the late 1980s, 90% of the contractors and 75% of the operators had received no formal training.

Social and psychological factors are likely to play a major role in determining the impact of risk and stress. Psychological factors featured prominently among the causes given by forest workers in Germany for accidents they suffered. About 11% of the accidents were attributed to stress and another third to fatigue, routine, risk taking and lack of experience. Internal cognitive models may play a significant role in the creation of risk situations leading to logging accidents, and that their study can make an important contribution to prevention.


Promising work on risk perception, assessment and risk taking in forestry has been done in Finland. The findings suggest that workers develop internal models about their jobs which lead to the development of automatic or semi-automatic routines. The theory of internal models describes the normal activity of a forest worker, like chain-saw or forest machine operation, the changes introduced through experience, the reasons for these and the creation of risk situations (Kanninen 1986). It has helped to provide a coherent explanation for many accidents and to make proposals for their prevention.

According to the theory, internal models evolve at successive levels through experience. Kanninen (1986) has suggested that in chain-saw operations the motion-control model is the lowest in the hierarchy of such models, followed by a tree handling model and a work-environment model. According to the theory, risks develop when the forest worker’s internal model deviates from the objective requirements of the situation. The model may not be sufficiently developed, it may contain inherent risk factors, it may not be used at a particular time (e.g., because of fatigue) or there may be no model that fits an unfamiliar situation—say, a windfall. When one of these situations occurs, it is likely to result in an accident.

The development and use of models is influenced by experience and training, which may explain the contradictory findings of studies on risk perception and assessment in the review by Slappendel et al. (1993). Forest workers generally consider risk-taking to be part of their job. Where this is a pronounced tendency, risk compensation can undermine efforts to improve work safety. In such situations workers will adjust their behaviour and return to what they accept as a level of risk. This may, for example, be part of the explanation for the limited effectiveness of personal protective equipment (PPE). Knowing that they are protected by cut-proof trousers and boots, workers go faster, work with the machine closer to their body and take short cuts in violation of safety regulations that they think “take too long to follow”. Typically, risk compensation seems to be partial. There are probably differences among individuals and groups in the workforce. Reward factors are probably important to trigger risk compensation. Rewards could be reduced discomfort (such as when not wearing warm protective clothing in a hot climate) or financial benefits (such as in piece-rate systems), but social recognition in a “macho” culture is also a conceivable motive. Worker selection, training and work organization should attempt to minimize incentives for risk compensation.

Mental Workload and Stress

Stress may be defined as the psychological pressure on an individual created by a perceived mismatch between that individual’s capacity and perceived demands of the job. Common stressors in forestry include high work speed; repetitive and boring work; heat; work over- or underloads in unbalanced work crews; young or old workers trying to achieve sufficient earnings on low piece-rates; isolation from workmates, family and friends; and a lack of privacy in camps. They can also include a low general social status of forest workers, and conflicts between loggers and the local population or environmental groups. On balance, the transformation of forest work that sharply increased productivity also pushed up stress levels and reduced overall welfare in forest work (see figure 2).

Figure 2.  Simplified scheme of cause-and-effect relations in contracting operations.


Two types of workers are particularly prone to stress: harvester operators and contractors. The operator of a sophisticated harvester is in a multiple-stress situation, because of the short work cycles, the quantity of information that needs to be absorbed and the large number of fast decisions that need to be made. Harvesters are significantly more demanding than more traditional machines like skidders, loaders and forwarders. In addition to machine handling, the operator is usually also responsible for machine maintenance, planning and skid track design as well as bucking, scaling and other quality aspects that are closely monitored by the company and that have a direct impact on pay. This is particularly true in thinnings, as the operator typically works alone and makes decisions that are irreversible. In a study of thinning with harvesters, Gellerstedt (1993) analysed the mental load and concluded that the operator’s mental capacity is the limiting factor for productivity. Operators who were not able to cope with the load were unable to take enough micropauses during the work cycles and developed neck and shoulder problems as a result. Which of these complex decisions and tasks is perceived as most demanding varies considerably among individuals, depending on factors like background, previous work experience and training (Juntunen 1993, 1995).

Added strain may result from the rather common situation in which the operator is also the machine owner, working as a small contractor. This implies a high financial risk, often in the form of a loan involving up to US$1 million, in what often is a very volatile and competitive market. Working weeks often exceed 60 hours for this group. Studies of such contractors show that the ability to withstand stress is a significant factor (Lidén 1995). In one of Lidén’s studies in Sweden, as many as 54% of machine contractors were considering leaving the job—first, because it interfered too much with their family life; second, for health reasons; third, because it involved too much work; and, fourth, because it was not profitable. Researchers and contractors themselves consider resilience to stress as a precondition for a contractor to be able to stay in business without developing serious health complaints.

Where the selection process works, the group may show few mental health complaints (Kanninen 1986). In many situations, however, and not only in Scandinavia, the lack of alternatives locks contractors into this sector, where they are exposed to higher health and safety risks than individuals whose personal profile is more in line with that of the job. Good cabins and further improvement in their design, particularly of controls, and measures taken by the individual, such as regular short breaks and physical exercise, can go some way towards reducing such problems. The theory of internal models could be used to improve training to increase the operator-contractors’ readiness and ability to cope with ever more demanding machine operation. That would help lower the level of “background stress”. New forms of work organization in teams involving task variety and job rotation are probably the most difficult to put into practice, but are also the potentially most effective strategy.



Saturday, 12 March 2011 17:38

Physical Load

Manual Forest Work

Workload. Manual forest work generally carries a high physical workload. This in turn means a high energy expenditure for the worker. The energy output depends on the task and the pace at which it is performed. The forest worker needs a much larger food intake than the “ordinary” office worker to cope with the demands of the job.

Table 1 presents a selection of jobs typically performed in forestry, classified into categories of workload by the energy expenditure required. The figures can give only an approximation, as they depend on body size, sex, age, fitness and work pace, as well as on tools and working techniques. It does, however, give a broad indication that nursery work is generally light to moderate; planting work and harvesting with a chain-saw moderate to heavy; and manual harvesting heavy to very heavy. (For case-studies and a detailed discussion of the workload concept applied to forestry see Apud et al. 1989; Apud and Valdés 1995; and FAO 1992.)

Table 1. Energy expenditure in forestry work.


Kj/min/65 kg man    

Workload capacity





Work in forestry nursery

Cultivating tree plants




















Clearing draining ditches with spade





Tractor driving/harrowing while sitting





Planting by hand





Planting by machine





Work with axe-Horizontal and perpendicular blows

Weight of axe head

Rate (blows/min)




1.25 kg





0.65-1.25 kg





Felling, trimming, etc. with hand tools






Carrying logs





Dragging logs





Work with saw in forest

Carrying power saw





Cross-cutting by hand





Horizontal-sawing power saw





Mechanized logging





Operating harvester/forwarder





Fuelwood preparation

Sawing small logs by hand





Cleaving wood





Dragging firewood





Stacking firewood





L = Light; M = Moderate; H = Heavy; VH = Very heavy; EH = Extremely heavy

Source: Adapted from Durnin and Passmore 1967.

Musculoskeletal strain. Manual piling involves repeated heavy lifting. If the working technique is not perfect and the pace too high, the risk of musculoskeletal injuries (MSIs) is very high. Carrying heavy loads over extended periods of time, such as in pulpwood harvesting or fuelwood harvesting and transport, has a similar impact.

A specific problem is the use of maximum body force, which could lead to sudden musculoskeletal injuries in certain situations. An example is bringing down a badly hung-up tree by using a felling lever. Another is “saving” a falling log from a pile.

The work is done using only muscle force, and most often it involves dynamic and not simply repetitive use of the same muscle groups. It is not static. The risk for repetitive strain injuries (RSIs) is usually small. However, working in awkward body positions can create problems such as low-back pain. An example is using an axe to delimb trees which are lying on the ground, which requires working bent over for long periods of time. This puts great strain on the lower back and also means that the muscles in the back do static work. The problem can be reduced by felling trees across a stem that is already on the ground, thus using it as a natural workbench.

Motor-Manual Forest Work

The operation of portable machines such as chain-saws may require even greater energy expenditure than manual work, because of their considerable weight. In fact, the chain-saws used are often too big for the task at hand. Instead, the lightest model and the smallest guide bar possible should be used.

Whenever a forest worker who uses machines also does the piling manually, he or she is exposed to the problems described above. Workers have to be instructed to keep the back straight and to rely on the big muscles in the legs to lift loads.

The work is done using machine power and is more static than manual work. The operator’s work consists of choosing, moving and holding the machine in the right position.

Many of the problems created originate from working at a low height. Delimbing a tree that is lying flat on the ground means working bent over. This is a similar problem to that described in manual forest work. The problem is compounded when carrying a heavy chain-saw. Work should be planned and organized so the working height is close to the hip of the forest worker (e.g., using other trees as “workbenches” for delimbing, as described above). The saw should be supported by the stem as much as possible.

Highly specialized motor-manual work tasks create very high risk for musculoskeletal injuries since the work cycles are short and the specific movements are repeated many times. An example is the fellers working with chain-saws ahead of a processor (delimbing and cutting). Most of these forest workers that were studied in Sweden had neck and shoulder problems. Doing the whole logging operation (felling, delimbing, crosscutting and certain not-too-heavy piling) means the job is more varied and the exposure to specific unfavourable static, repetitive work is reduced. Even with the appropriate saw and a good working technique, chain-saw operators should not work more than 5 hours a day with the saw running.

Machine Work

The physical workloads in most forest machines are very low compared to manual or motor-manual work. The machine operator or the mechanic is still sometimes exposed to heavy lifting during maintenance and repairs. The operator’s work consists of guiding the movements of the machine. He or she controls the force to be exerted by handles, levers, buttons and so on. The work cycles are very short. The work for the most part is repetitive and static, which can lead to a high risk for RSIs in the neck, shoulder, arm, hand or finger regions.

In machinery from the Nordic countries the operator works only with very small tensions in the muscles, using mini–joy sticks, sitting in an ergonomic seat with armrests. But still RSIs are a major problem. Studies show that between 50 and 80% of machine operators have neck or shoulder complaints. These figures are often difficult to compare since the injuries develop gradually over a long period of time. The results depend on the definition of injury or complaints.

Repetitive strain injuries depend on many things in the work situation:

Degree of tension in the muscle. A high static or repeated, monotonous muscle tension can be caused, for example, by using heavy controls, by awkward working positions or whole-body vibrations and shocks, but also by high mental stress. Stress can be generated by high concentration, complicated decisions or by the psychosocial situation, such as lack of control over the work situation and relations with supervisors and workmates.

Time of exposure to static work. Continuous static muscle tensions can be broken only by taking frequent pauses and micropauses, by changing work tasks, by job rotation and so on. A long total exposure to monotonous, repetitive work movements over the years increases the risk of RSIs. The injuries appear gradually and may be irreversible when manifested.

Individual status (“resistance”). The “resistance” of the individual changes over time and depends on his or her inherited predisposition and physical, psychological and social status.

Research in Sweden has shown that the only way to reduce these problems is by working with all these factors, especially through job rotation and job enlargement. These measures decrease the time of exposure and improve the well-being and psychosocial situation of the worker.

The same principles can be applied to all forest work—manual, motor-manual or machine work.

Combinations of Manual, Motor-Manual and Machine Work

Combinations of manual and machine work without job rotation always mean that the work tasks become more specialized. An example is the motor-manual fellers working ahead of a processor which is delimbing and cutting. The work cycles for the fellers are short and monotonous. The risk of MSIs and RSIs is very high.

A comparison between chain-saw and machine operators was made in Sweden. It showed that the chain-saw operators had higher risks of MSIs in the low back, knees and hip as well as high risks of hearing impairment. The machine operators on the other hand had higher risks of RSIs in the neck and shoulders. The two types of work were subject to very different hazards. A comparison with manual work would probably show still another risk pattern. Combinations of different types of work tasks using job rotation and job enlargement give possibilities to reduce the time of exposure for many specific hazards.



Page 12 of 16

" DISCLAIMER: The ILO does not take responsibility for content presented on this web portal that is presented in any language other than English, which is the language used for the initial production and peer-review of original content. Certain statistics have not been updated since the production of the 4th edition of the Encyclopaedia (1998)."


Part I. The Body
Part II. Health Care
Part III. Management & Policy
Part IV. Tools and Approaches
Part V. Psychosocial and Organizational Factors
Part VI. General Hazards
Part VII. The Environment
Part VIII. Accidents and Safety Management
Part IX. Chemicals
Part X. Industries Based on Biological Resources
Part XI. Industries Based on Natural Resources
Part XII. Chemical Industries
Part XIII. Manufacturing Industries
Part XIV. Textile and Apparel Industries
Part XV. Transport Industries
Part XVI. Construction
Part XVII. Services and Trade
Part XVIII. Guides