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68. Forestry

Chapter Editor: Peter Poschen


Table of Contents

Tables and Figures

General Profile
Peter Poschen

Wood Harvesting
Dennis Dykstra and Peter Poschen

Timber Transport
Olli Eeronheimo

Harvesting of Non-wood Forest Products
Rudolf Heinrich

Tree Planting
Denis Giguère

Forest Fire Management and Control
Mike Jurvélius

Physical Safety Hazards
Bengt Pontén

Physical Load
Bengt Pontén

Psychosocial Factors
Peter Poschen and Marja-Liisa Juntunen

Chemical Hazards
Juhani Kangas

Biological Hazards among Forestry Workers
Jörg Augusta

Rules, Legislation, Regulations and Codes of Forest Practices
Othmar Wettmann

Personal Protective Equipment
Eero Korhonen

Working Conditions and Safety in Forestry Work
Lucie Laflamme and Esther Cloutier

Skills and Training
Peter Poschen

Living Conditions
Elías Apud

Environmental Health Issues
Shane McMahon

Tables

Click a link below to view table in article context.

1. Forest area by region (1990)
2. Non-wood forest product categories & examples
3. Non-wood harvesting hazards & examples
4. Typical load carried while planting
5. Grouping of tree-planting accidents by body parts affected
6. Energy expenditure in forestry work
7. Chemicals used in forestry in Europe & North America in the 1980s
8. Selection of infections common in forestry
9. Personal protective equipment appropriate for forestry operations
10. Potential benefits to environmental health

Figures

Point to a thumbnail to see figure caption, click to see figure in article context.

FOR010F1FOR010F2FOR010F3FOR010F4FOR010F5FOR020F4FOR020F5FOR020F6FOR030F6FOR030F7FOR030F8FOR050F1FOR070F2FOR070F1FOR130F1FOR130F2FOR180F1FOR190F1FOR190F2


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Monday, 14 March 2011 17:51

Skills and Training

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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.

 

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Monday, 14 March 2011 17:53

Living Conditions

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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

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.

Comments

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.

 

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Monday, 14 March 2011 17:55

Environmental Health Issues

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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

 Harvesting

 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.

 

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Contents

Preface
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