Table of ContentsNext Page


Environmentally Sound Forest Harvesting Operations


Rudolf Heinrich

Forest Harvesting, Trade and Marketing Branch

Forest Products Division

Forestry Department, FAO, Rome, Italy


World forestry is challenged by a number of issues such as the loss of the earth's biodiversity, forest decline because of air pollution and transformation of old growth forests in the temperate region, decrease of forest land due to conversion to other land uses in tropical countries, forest land degradation and tree stand impoverishment as well as generation of forest waste caused by inappropriate and unsustainable forest harvesting practices. Recently issues such as labelling of wood products, suggestions for trade restrictions and even boycotts of tropical timber from non-sustainably managed forests have emerged as further causes of concern in forest and wood products development.

Although great advances have been made during the last two decades in developing and introducing highly mechanised and specialised machinery in forest operations, which permit environmentally sound, economically profitable and socially acceptable forest uses to support sustainable forest development, there still is a great need to ensure the introduction and application of appropriate policies and practical codes of environmentally friendly harvesting practices with the aim to advance sustainability of both timber and non-timber forest products.

Worldwide in 1991, some 3.4 billion m3 of round wood (FAO 1993) have been removed from the world's forests of which a little bit less than half has been used for industrial purposes and the other half as fuelwood. The presently existing forest resources worldwide are estimated to amount to about 4.1 million ha. With an ever increasing rate of deforestation for other land uses (conversion to agricultural land, infrastructure, and urbanisation; presently the rate of forest decrease in the tropics alone amounts to some 15.4 million ha annually), it is evident that a concerted effort is needed to motivate policy makers, managers, technicians and forest operators to encourage forest development programmes that harmonise interests in conserving forests as well as to wisely use the potential of the forest while maintaining its full regeneration capacity.


At the United Nations Conference on Environment and Development (UNCED) held in 1992 in Rio de Janeiro, forestry received major attention under Agenda 21, Chapter 11 entitled "Combating Deforestation". With respect to forest use, particular reference was made to the need to promote efficient utilisation and assessment to recover the full valuation of goods and services provided by forest lands and woodlands (UNCED 1992). In many forest operations, we can recognize that the full potential of forests and forest lands is far from being realised as a major source for development.

A prerequisite for sustainable forest utilisation is comprehensive pre-harvest planning, appropriate monitoring and execu-tion of operations as well post-har-vest evalu-ations, increasing the production of goods and services, particularly in broadening diversity of yield of forest use, covering timber and non-timber forest products. This should help to generate more income and employment; enhancing life of rural populations, without compromising the regenerative capacity of the forests and their continued contribution to human welfare, while satisfying the aspirations of goods and services for future generations.

There are numerous definitions of sustainability. In 1904, G.L. Hartig, Head of the Prussian Forest Administration in Berlin, defined sustainability as follows:

"Every wise forest director has to have evaluated the forest stands to utilise them to the greatest possible extent, but still in a way that future generations will have at least as much benefit as the living generation".

On the subject of sustainable development, in 1988 the FAO Council adopted the following definition:

"The management and conservation of the natural resource base and the orientation of technological and institutional change in such a manner as to ensure the attainment and continued satisfaction of human needs for present and future generations. Such sustainable development conserves land, water, plant and animal genetic resources and is environ-mentally non-degrading, technically appropriate, economical-ly viable and socially acceptable".

Perhaps the most widely quoted definition of sustainable development is that of the Brundtland Commission (WCED 1987): "development that meets the needs of the present without compromising the ability of future generations to meet their own needs".

In view of the dwindling resources due to forest decline in the temperate zone, conversion to other land uses and degradation in the tropical areas, it is essential that forest harvesting practices are carried out in a manner to guarantee the sustainability of the forest resource base.

It is well recognised that the complexity and diversity of the vegetative cover as well as the fauna of the various forests require well planned and controlled forest operations and interventions to make full use of the potential of wood and non-wood forest products, compatible with environmental conservation. In some instances, the optimal use of all forest products may not be feasible due to factors, which include environment, accessibility, availability of harvesting technology, resources, laws and regulations.


FAO's perception of forest harvesting in relation to socio-economic development has gone through a substantial evolution. In forestry, a concept which needs to be more frequently introduced is the use of a wider range of forest products based on sustainable resource management. In addition to timber, a multitude of non-wood products are available from the forests which can be most beneficial in terms of employment and income generation, particularly for the local population. In many instances, harvesting is no longer synonymous with logging as it deals with a wide array of non-wood outputs (de la Cruz 1989). A partial list of such products may include plants for ornamental and medicinal use; honey, resins, tannin, fruits, mushrooms, nuts, wildlife for food and hunting trophies. Harvesting may be defined as the procurement of raw materials from the forests. When recognizing this new approach, harvesting as an independent technical discipline has to be seen as an integrating function forming a strong link between the resources, forest-based enterprises and markets. FAO, besides its traditional work in wood harvesting, has recently developed an action programme on harvesting of non-wood forest products and has undertaken case studies on small-scale harvesting that includes increased involvement by the local population. This was published as FAO Forestry Paper No. 87 (de la Cruz 1989). A study was also made on the collection, processing and marketing of edible mushrooms from forest plantations in Chile (Donoso and Kilkki 1993). By 1990 the value of these mushrooms had reached about US$ 3 million annually.


In responding to the urgent needs to enhance environmentally sound and sustainable forest harvesting practices worldwide and supporting the transfer of appropriate technology, FAO has created a network of communication among scientists and practitioners from industrialised and developing countries. The FAO Forest Harvesting Bulletin is published twice annually and allows for the sharing of information and experiences relating the new development in forest engineering, harvesting and transport.


The aim of the FAO Forest Harvesting Bulletin is to promote environmentally sound forest practices worldwide. The bulletin reports on FAO's programmes and activities in this field of specialisation, highlighting emerging issues and conflicts and reporting on new advances made to reduce the environmental impact of forest harvesting on forest stands, soil and terrain; improving timber utilisation; generating employment and income; preventing forest workers accidents and limiting health risks in forest operations.

The eight-page four-colour newsletter has now a worldwide distribution of nearly 4,000 copies per issue. The membership list of this network incorporates forest engineering specialists, forest planning and policy personnel, forest operations managers, technicians and forest workers; national and international civil servants interested in forestry matters and representatives of grass roots level movements.

Presently the Forest Harvesting Bulletin is sent to institutions such as government forest administrations, forest universities, technical schools, training centres, research institutes, forestry libraries, forest and forest industries enterprises, forest operation contractors, non-governmental organisations, FAO/UNDP Regional and Country Representations and to the Regional Development Banks and the World Bank.

The suggestion to establish a worldwide network in the field of forest engineering, harvesting and transport emanated from recommendations made at the expert consultation on the FAO Action Programme on Forest Harvesting Training held from 23-27 April 1990 in Kotka, Finland. The FAO Forest Harvesting Bulletin essentially contains an editorial, featuring forest harvesting issues viewed in a general context; reports on the application of new technologies in forest road planning, construction, harvesting and transport, activities undertaken by national or international organisations in particular by ILO, UNIDO, ISO, ITTO, UNEP, etc., as well as meetings related to engineering and harvesting.


The overall purpose of this programme is to contribute to sustainable development by devising, testing, and helping to implement improved technologies for timber harvesting in tropical forests. Timber harvesting is considered here to comprise the aggregation of all operations relating to the felling of trees and the extraction of their stems or other usable parts from the forest for subsequent processing into industrial products. The term harvesting technology refers to the application of scientific and engineering principles, in combination with education and training, to improve the application of labour, equipment, and operating methods in the harvesting of industrial timber.

Activities being developed under this programme stem directly from critically needed tasks as identified in the Rio Declaration and in Chapter 11 of Agenda 21. For instance, Principle 4 of the Rio Declaration notes that "In order to achieve sustainable develop-ment, environmental protection shall constitute an integral part of the development process and cannot be considered in isolation from it." Principle 11 says in part that "States shall enact effective environmental legislation" and Principle 17 reads "Environmental impact assessment, as a national instrument, shall be undertaken for proposed activities that are likely to have a significant adverse impact on the environ-ment and are subject to a decision of a competent national authority." Similarly, Chapter 11 of Agenda 21 states that "unsustainable commercial logging" must be halted, that it is essential to develop "environmentally sound methods and practices of forest harvesting which are ecologically sound and economically viable," and that forestry must contribute to both economic development and environmental protection by endeavouring to develop "efficient conversion technology and improved sustainable utilization of harvesting and process residues".

The major activities for the Programme on Environmentally Sound Harvesting Tech-nol-ogies to Sustain Tropical Forests, as currently being planned by the FAO Forest Har-vesting and Transport Branch under the Forest Products Division, are listed below. To the extent possible, these activities are being initiated under FAO's Regular Programme but external funding will be needed for their full implementation.


In a survey of training needs carried out by FAO with the support of the Forestry Training Programme of Finland in 29 countries, it became evident that due to the temporary nature of forest operations as a seasonal work, there is a high turn over of forestry personnel.

This certainly will have a great impact on the needs of training facilities; types and curricula of training; extension, and educational programmes. In general, it was observed that the subject area forest engineering, harvesting and transport had a time share of 10-15% of the total curriculum at Forestry Universities.

At the technical level, reduced versions of the university curricula were taught. Training at the vocational level was the most needed. A considerable shortage of training facilities and appropriate training material has been noted.

The Forest Harvesting and Transport Branch with the assistance of various bilateral donor agencies, has dedicated a considerable effort to carry out various training courses, workshops, seminars and expert consultations on a broad range of topics covering planning and management of forest operations; health and safety issues in forestry work; the transfer and use of appropriate harvesting technology; mountain logging; forest road planning and construction; forest operations in the tropics; forest harvesting and environment.

A recent initiative under this programme is the Seminar on Economics and Management of Forest Operations for Countries in Transition to Market Economies, which was held in Ort/Gmunden, Austria from 27 June to 2 July 1994.

The objectives of the seminar are to provide participants with some basic information on the principles of economically efficient and environmentally sound forest harvesting and engineering operations in the context of a market oriented economic system.

Special efforts were devoted to highlight legal, institutional, organisational and administrative measures through government services and support programmes of the Boards of Agriculture and Forestry in order to enhance the development of private forest enterprises based on the Austrian experience.

Participants had an opportunity to share experience and information by presenting their country reports, highlighting the success, problems and difficulties encountered in transforming centrally planned enterprises into market oriented enterprises. In this context, information was provided on the countries' forestry situation, legislation, types and sizes of forestry enterprises, level and choice of technology, production systems, employment and income, environmental issues, forest extension, training, education and research.


The FAO Forest Harvesting and Transport Branch has established a computerised data base on forest engineering, harvesting and transport machinery, equipment and tools of main manufacturing companies and suppliers throughout the whole world. Presently the system contains information on more than 240 companies worldwide.

The information available comprises a wide range of equipment; incorporating basic, intermediate and most advanced mechanised harvesting technology and systems. The aim of the data base is to provide more efficiently technical services in assisting governmental, non-governmental and private forest enterprises to select appropriate equipment and machinery in relation to their socio-economic needs and forestry conditions.

Based on the experience in various field projects, data have been also collected on productivity and costs of various types and systems in forest harvesting. As a result of this data base, rapid evaluations on productivity and costs in forest harvesting can be undertaken.

The establishment of these data bases has greatly increased the efficiency and capacity of technical backstopping in FAO member countries in this field of competence.


In countries as diverse as Sweden and Japan it has been estimated that the economic value of non-wood forest products amounts to between 20 and 25% of the value of wood products. Non-wood forest products are even more important to the economies of many developing countries. A few well-known examples include Brazil nuts, rubber, palm hearts, mushrooms, honey and beeswax, rattan, and bamboo. These products, and many others which are not so well known but are often more important to local people, have the potential to enhance the value of standing forest and therefore reduce the likelihood of deforestation. Harvesting, transportation and storage techniques for non-wood forest products are often complicated because of short harvesting seasons in which timing and rapid delivery to markets can be critical. FAO is working with specialists in non-wood forest products to develop improved harvesting, processing and storage techniques in order to help maximize the contribution of these products to income and employment in rural communities.


The Forest Harvesting and Transport Branch has created a new series of special reports on Forest Harvesting Case Studies which deals with innovative systems and techniques to improve harvesting standards, productivity, costs, and reduce the environmental impacts of forest operations. The aim of these studies is to thoroughly document environmentally sound and sustainable forest utilisation technology which could be of interest to many forest enterprises in a number of countries.

Two recently published studies under this series dealt with reduction of wood waste and non-wood forest products. They are:

Further studies expected to be published will deal with:

For training purposes, a few practical oriented manuals have been prepared. Two were published under the FAO Training Series: the Chainsaw Manual and the Design Manual on Basic Wood Harvesting Technology.

The aim of the design manual is to provide ideas for techniques and equipment that will improve productivity at little or no investment; encourage the use of local skills and materials, and promote and encourage the involvement of the local population in forest utilisation. The equipment suggested in this manual is simple and inexpensive to make; reduces work loads and thus energy demands of human labour, and can easily be made from locally available materials in modest blacksmith shops, maintenance facilities of local communities or at the site of the task at hand.

Two further training materials were prepared on Cable logging and forest road planning and construction, subjects which require a very special training effort due to the complicated nature of the activities.

Many publications of the FAO Forestry Department's series, the FAO Forestry Papers, have had a major focus on forest harvesting and transport in the 110 papers published in this series. Since its inception in 1977, 15 papers have been devoted largely to issues relating to forest harvesting and transport.

The series is aimed at scientists and educators; professional people working in forestry or related fields, and high level decision makers, whose judgements may influence the future course of forest conservation and development.


De la Cruz, Virgilio. 1989. Small-Scale Harvesting Operations of Wood and Non-Wood Forest Products Involving Rural People. FAO Forestry Paper 87. Rome.

FAO. 1993. Yearbook of Forest Products 1991. Rome.

Donoso J., and Kilkki, R. 1993. Cosecha de Hongos en la VII Región de Chile. FAO, Rome.

UNCED. 1992. United Nations Conference on Environment and Development, final advanced version of Agenda 21, Chapter 11, Combating Deforestation.

WCED. 1987. Our Common Future. World Commission on Environment and Develop-ment, convened by the United Nations General Assembly, New York. Oxford University Press, Oxford, UK.

Environmentally Sound Forest Harvesting in the Finnish Context


Rihko Haarlaa

Department of Forest Resource Management

University of Helsinki, Finland


In Finland, sustainable forestry has been practised for centuries and environmental protection aspects have always been considered in forest management and wood harvesting practices. The mechanization of forest work has been fast during the past decades. More than 80% of manual wood cutting has been replaced by harvester operations. Wood transportation by horse was given up about 20 years ago; subsequently agricultural tractors and later the specially designed forest tractors, the forwarders, have been used for off-road wood transportation. The main reasons behind this development are the higher productivity and the lower costs resulting from the use of these new methods. However, eventual damages caused to nature as well as other environmental aspects are gaining increasing importance in the decision-making process when deciding on actions to be taken and machinery to be used in forest operations.


Finland is a country where the forests have always played a central role in the life of the people. Sustainable forestry has been practised during the centuries to the point that the growing stock has increased so much, that today there is more wood in Finland than ever before. During the last 50 years, sound forest management practices have been systematically followed, unproductive sites have been made productive and the results from forest research have been applied, even in private forestry, thanks to the efficiency of Finnish extension organizations. At the same time, issues like saving nature's biodiversity, protecting unique nature biotopes, reserving large areas for nature parks, etc., have also been given special thought.

Forest management is a dynamic and long-term process along which the views of citizens change. Today, the ecological treatment of forests is of paramount importance. The maximum wood production, the use of the most efficient wood harvesting methods as well as securing employment to the people living in the country-side, are no longer the most essential and single goals of forest management.

Furthermore, the environmental issues of forest management are also key topics of an active forest research. Scientists need, for example, to find quantitative values for the various forms of forest utilization, identify the ecological consequences of alternative silvicultural actions, develop the thinning and regeneration regimes to be more ecological, improve the tending of seedling stands and monitor the negative effect of acid rain on forests. One interesting topic for research and development activities has been the development of environmentally sound technology for forestry. In this context, Finns are proud to present an approach that could be successfully adopted and used in any part of the world.


In the management of Finland's forests, the environmental protection aspects have always been duly considered by forestry staff. A sustained yield from the forests has never been possible without considering the requirements set by nature. Sixty-two percent of Finland's land area is classified as forests, and 87% of the total area is the so-called "forestry land" serving as drainage areas for lakes and rivers. Thus, the benefit from natural resources, especially from forests, swamps and waters, essentially depends on the activities led by forestry professionals. The meaningful utilization and protection of these renewable natural resources concern, one way or the other, forest owners, professional foresters and forest industry.

The following three topics have been mentioned (e.g., IUCN, WWF, UNEP) as the leading principles for the utilization of natural resources.

From the forest ecological point of view, all actions which support the natural development of forests should be favoured. A joint use of forests for wood production and recreational purposes that simultaneously maintain the prevailing landscape is the goal to be pursued.

Since one third of Finland's land area is covered with peat, the drainage of peatlands, as well as the fertilization of both mineral and peat soils for promoting tree growth, have been common topics in public discussion among the many environmental issues.

Obviously, environmental protection and silvicultural measures are always going to be somewhat in conflict insofar as many environmentalists consider that only reserved parks are natural forests. However, a type of forest management that relies on native tree species and follows the common and quite well-known laws of nature, can successfully fulfil the target of environmentally sound forest management. The speed at which stands and single trees develop can be favourably influenced by human interventions. And today, changes in the landscape take place mostly due to silvicultural measures rather than natural phenomena, e.g., fires, like in passed centuries.

The meaning of clear-cutting operations is not only to harvest the wood crop grown in an area, but also to make the necessary reforestation possible. Trees are unable to live forever and thus young generations are needed to preserve the forest. There are several important planning aspects to be considered, e.g., when drawing the border lines for a cutting area, or when deciding on the size of each uniform reforestation area.

The stand establishment may be carried out either in a natural way, by help of seed trees, or artificially, by sowing or planting. Here, the well-chosen soil preparation method, leaving less-useful trees standing for birds in a clear-cut area, etc., may soften the shock caused by the emergence of a reforestation area in the landscape. Later, the treatment of the seedling stand, if at the right time, can favour the closing of the canopy of trees.

Thinning operations have always been carried out according to efficient forest management. For example, in a mixed stand, selective cutting regulates tree species composition and favours preferred species. On the other hand, if some minor spots are left untouched, good areas for game life are provided, thus breaking _ at least partly _ a standardized treatment of the stand. For the thinning operations, work methods need to be chosen carefully so as to avoid the construction of broad strip roads, damages to the remaining trees, etc.

There always are some points in the landscape which, from a scenic point of view need to be kept untouched or handled with special care. In Finland, the islands with thousands of lakes and the coastal forests of the Baltic Sea are good examples of this. Some rocky areas or other uncommon types of terrain are sometimes also worth receiving attention when deciding on the stand treatment in forest management (Hänninen et al. 1992).

In an efficient forest management, some basic improvement work will also be done. In Finland, operations such as drainage of waterlogged sites, fertilization and construction of forest roads form part of such work. Avoiding erosion and leakage of nutrients to water courses as well as locating roads in the forest area according to the features of terrain, are aspects that need attention (HÄNNINEN et al. 1995).

It is worth stressing that environmental protection and forest management are not separate issues. When planning forest management, the planner must consider the important environmental protection aspects and work out the plan in such a way that there are no conflicts. In most cases, this is fully possible, e.g., in state forests (Korhonen et al. 1994).


The mechanization of forest work has been rapid during the past decades. More than 80% of the manual wood cutting has been replaced by harvester operations. The transport of wood by horses was discontinued some 20 years ago. The agricultural tractors and later the specially designed forest tractors, the forwarders, have been in use for the off-road transport of wood. The main reasons behind this development have been the higher productivity and the lower costs resulting from the use of these new methods. However, eventual damages caused to nature and other environmental aspects are now gaining increasing importance in the decision-making process when determining what actions to take and what machinery to use in forest operations.

When the manual wood cutting with chain saws was practised, no serious complaints regarding environmental protection were expressed by public opinion. Ergonomics of the forest workers have improved with the use of better tools and better working methods. Today, the introduction of vegetative instead of mineral oils for chain saws is under discussion and in wide use. There are technically acceptable vegetative oils on the market, but their price is still somewhat a problem.

As soon as mechanized wood cutting methods were introduced, damages caused to the remaining trees and to the soil of the cutting site were recognized. In the case of thinning operations, for example, the machinery used in old times was clumsy and the operators, used to clear-cutting operations, were not accustomed to silviculturally selective cutting and they often damaged the remaining trees. With the introduction of cranes and forwarders, machines' movement could be restricted to strip roads thus reducing damages on standing trees considerably, as well as limiting soil compaction. Recently, with improved mobility, larger and broader tires, wheeled tractors are able to manoeuvre, even on a quite soft unfrozen soil, without causing excessive rutting and soil compaction.


Under this section, attention will only be paid to the effects wood cutting has on the environment and to aspects related to the remaining stand; the strip road network, and the eventual damages being caused to the trees and the ground.

The trees left in a selective cutting must be able to fully utilize the wood production capacity of the site. The density of the stand should not be too low after the cutting. The quality of the trees should genetically represent the best part of the unthinned stand. There are recommendations for stand density based on the height of the trees and the basal area.

The strip road network should be designed in such a way that all timber being cut can be transported away from the forest in due course. The spacing of the strip roads should be as wide as the reach of the crane and the forwarder allows. In Finland, the spacing is 20 to 30 m depending on the harvesting method. The width of the strip road should also correspond to the harvester and transport vehicle being used. In young thinning stands, the width of strip roads is 4 meters at the most.

A system and a code have been developed for measuring the damages on the remaining trees (Lilleberg et al. 1991). These are classified as stem, root collar and root wounds. Only a wound located closer than 70 cm from the stem and the wounds in roots thicker than 2 cm are recorded. Wounds of about 100 cm2 of area and bigger ones are recorded separately. The depth and length of the ruts caused by the vehicles are measured systematically.

For the use by the authorities, the code includes two steps:

The evaluation includes a visit to the field with a logging map for orienteering. The ocular observations are completed with relascope measurements and tape. The report from this survey is delivered to the forest owner, the logging body (e.g., the contractor) and the association of the forest owners.

The detailed measuring includes a systematic survey of the whole cutting area with accurate recording of the basal area and other stand data as well as strip road characteristics, and eventual damages. The results of the survey are then compared with guiding limit values that indicate whether the operation has been carried out successfully and in an acceptable manner. Further actions naturally depend on this comparison. In general, it is sufficient to evaluate a small proportion of the cutting site following this method.


In mechanized wood harvesting operations, waste liquids, scrap metal and other materials such as rubber are produced from time to time. Some of them are classified as problems and need special attention.

Many logging machines include a great amount of hydraulics; thus there is always the risk to have oil leakages when a pipe breaks or when other damages in the system arise. Even during service operations, careless handling of fuel or oil may lead to spilling these liquids into nature. A system whereby used mineral oils are disposed of in a safe and acceptable manner should be found, particularly as developments in the quality of lubrication are quite interesting. Vegetative oils for example, produced from turnip, rape, or pine oil, are not poisonous and dissolve biologically.

Moreover, when broken machine components are replaced, the scrap material should not be left in the forest nor at sides of forest roads. Too often empty barrels, broken tires, left-overs from an abandoned vehicle, etc., are found when travelling in the countryside. In Finland, a public system exists to clean roadsides, charging the costs to those who littered the streets and highways. Recycling is extensively winning ground today.


As indicated above, there are numerous and complicated problems when looking at the environmental aspects of forest work. It is obvious that mistakes have been made in the past. However, foresters are in the advantageous position to be able to learn from mistakes and, accordingly, improve future operations. The author of this paper is convinced of the progressive developments being achieved in these areas. Moreover, by utilizing results in the right way, a balanced integration of well-managed forestry and nature protection can be guaranteed. A sign of such development is the recent introduction of a quality control system, according to the ISO 9002 standards, to wood harvesting operations in Finland.


Hänninen, E. et al. 1992. Metsäammattilainen. Ympäristönhoito (Forestry staff. Environment protection). Metsäteho. Helsinki. ISBN 951-673-128-7.

Hänninen, E. et al. 1995. Metsätalous ja vesiensuojelu (Forestry and protection of waters). Metsäteho. Helsinki. ISBN 951-673-142-2.

Korhonen, K.-M. et al. 1994. Forestry environment guide. Finnish Forest and Park Service. Helsinki. ISBN 951-45-6809-5.

Lilleberg, R. et al. 1991. Harvennushakkuiden korjuujäljelle asetettavat vaatimukset sekä korjuujäljen arviointi ja mittaaminen (Requirements set to the result in thinning and the evaluation and measuring of the result). Metsäteho. Helsinki. ISBN 951-673-119-8.

CATIE's Experiences in the Development of Low Impact Forest Harvesting Systems in Central America


David Quirós, José Joaquín Campos A., Fernando Carrera,

Froylán Castañeda, Robin aus der Beek

CATIE/COSUDE, Turrialba, Costa Rica


This paper discusses CATIE's experiences in the development of forest harvesting operations that aim at reducing the impact on the forest. The main factors affecting harvesting operations in the region (e.g., structure and composition of the forest site, and cultural, economic, institutional and political factors) are discussed. It shows how traditional forest harvesting operations in the region are in general highly destructive, mainly due to lack of proper planning and supervision in the implementation of the different operations, and lack of a competent and properly motivated workforce.

It discusses the different harvesting practices that are being implemented by CATIE throughout the region. These practices are grouped into three phases: pre-harvesting, harvesting, and post-harvesting. The pre-harvesting phase includes the following activities: preliminary inventory of the management unit; preparation of the general forest management plan (including the segregation of protection and production areas); planning inventory for the harvesting unit; preparation of the harvesting plan and workforce training. The harvesting plan includes, among other activities: selection and location of all commercial trees, seed trees, trees of endangered species, trees that are recognized as important for wildlife, as well as reserve trees for future harvests; forest roads design and elimination of vines before felling. The harvesting phase includes: construction of forest roads; directional felling; skidding; bucking, loading and transport; and the proper supervision of the implementation of these activities. Finally, the paper discusses the post-harvesting phase, which includes the recovery of timber residues; road repair and closure; and general site cleaning activities (removal of oil cans, fuel containers and other man-made debris).

KEYWORDS: forest harvesting, forest management, tropical forests, Central America.


Since the 1992 United Nations Conference on Environment and Development (UNCED 1992), there have been several initiatives aimed at improving the management, conservation and sustainable development of all types of forests (CIFOR 1995). In Central America, where almost two thirds of all forests have been lost (Pedroni and Flores 1992), particularly the humid tropical forests, there is a growing recognition that managing this kind of forest has become a more complex and more demanding discipline. As a consequence, the design and implementation of environmentally sound forest operations must consider the multiresource character of these forests.

Four elements are essential in relation to low impact forest harvesting systems: comprehensive harvest planning; effective implementation and control of harvesting operations; thorough post-harvest assessment; and development of a competent workforce (Dykstra and Heinrich, 1995).

Since 1990, the Tropical Agricultural Research and Higher Education Center (CATIE)/, has been designing and implementing applied research on different aspects related to the sustainable management of the tropical forests of Central America. The research conducted by CATIE has been carried out with the objective of contributing to the development and adoption of forest management systems that are ecologically sustainable, technically feasible, and economically attractive. Besides these criteria, forest management recommendations should be socially acceptable. The objective of this paper is to describe CATIE's experiences in the development of environmentally sound and cost-effective forest harvesting practices for the broadleaf humid forests of the region.


In order to better understand the problematic characteristics involved in logging operations in the region, the main factors that influence timber harvesting will be briefly analyzed.

Factors Influencing Timber Harvesting

Forest biomass

The humid broadleaf primary forests of the region are characterized by a negative exponential distribution (inverse "J" curve) with respect to the number of trees by diameter class. Basically, this distribution describes a forest with few large trees per hectare and an abundance of understorey vegetation and natural regeneration.

On average, these forests contain about 400 trees/ha over 10 cm dbh, and between 30 and 40 individuals greater than 50 cm dbh, which is generally the minimum diameter cut in the region. From those trees greater than the minimum diameter cut, 2 to 10 commercial trees are normally extracted in timber harvests.

These Central American forests are rich in tree species, and generally contain between 100 and 150 different tree species per hectare, although the number of species actually harvested is far fewer. Nevertheless, with recent wood scarcities in many countries, non-traditional species are being increasingly logged.

Geophysical factors

The annual precipitation averages at least 3,000 mm in the majority of Central American humid forests, with the heaviest rains falling between May and December. This long rainy season limits logging operations to only the driest months of the year.

The soils in areas still forested are, in general, infertile with high clay content, thus making them very susceptible to compaction, especially when wet. This factor restricts the machinery that can be used.

The combination of the aforementioned factors makes logging in tropical forests much more difficult than in temperate areas, before taking into account topographical differences. The remaining forests available for harvesting outside national parks are usually located in steep inaccessible areas, with no or poorly maintained road networks. A lack of adequate technology throughout the region further complicates logging activities. The sum of these factors along with the ever increasing agricultural frontier has left only small patches of unlogged forests.

Forest roads are generally constructed by loggers to gain access to valuable trees and as a consequence, rural people take advantage of these access points in their search for new agricultural land.

Socio-economic factors

An agricultural and cattle culture predominates throughout a large part of the population, with almost no forestry tradition. As a consequence, forests have been viewed not as a renewable resource, but rather, as an impediment to development.

The availability of skilled labour is also a limiting factor to low impact logging. Many tree fellers and heavy equipment operators do not receive training, and the skills they do have are acquired on the job.

With a sharply increasing population driving up wood demand, total forest area has significantly decreased. While this situation has lead to the logging of areas with difficult access, consequently complicating timber harvesting, it has also resulted in an increase in both sawn wood prices and the utilization of new species, along with the promotion of management in secondary forests.

Legal and institutional factors

In the majority of harvests, the logger is not the property owner and, as such, has no financial incentive to protect the remaining trees in the stand. Many forest landowners view logging as a means to cheaply obtain access roads on their property. They sell their harvestable trees at very low prices, with the idea of eventually changing the land use to more intensive agricultural or cattle applications.

Land tenure is one of the principal problems involved in sustainably managing Central American forests. The national forest services in these countries will not authorize logging permits unless the property owner can show legal right to the land. Many rural people cannot afford the fees required to obtain government land titles, thus encouraging illegal logging on their lands.

Government policies in general have deterred forest management. Less than a decade ago, property owners requesting bank loans were required to show that they had "improved" their lands, usually by deforesting and planting pasture grasses. In some Central American countries, all standing timber trees were considered state property, and government officials decided when and how many trees to sell on private land. However, now some Central American countries are promoting financial incentives to land holders provided that they put their forest under sustained management. While this new attitude is encouraging, many governments lack the funding to successfully implement these programmes.

Another major impediment to sound forest management practices is the lengthy, confusing, and costly bureaucratic paperwork required by most forest services in order to grant logging permits. Because of this problem, a great deal of the wood sold is illegal, consequently, exacerbating government corruption.

Characteristics of Traditional Timber Harvesting in the Region

Destructive character

The lack of planning and control in timber harvests, in the majority of Central American countries, leads to an activity that is destructive in character, working against principles of sustainability. Generally, the logger assumes all of the administrative responsibilities involved in timber extraction, under the condition that the standing trees are sold at a very low price, greatly under the real market value.

In some countries, this situation is slowly changing with the creation of new laws that require foresters to plan and better supervise logging operations. At first, many loggers resisted these changes; however, some are realizing that a better planned operation actually favours them financially.

Species selectiveness

In the region, timber extraction is characterized by its highly selective nature (high grading), and the number of species harvested is inversely proportional to the area still left forested. For example, in Costa Rica where only 4.3% of the total surface area is still forested (excluding protected areas), many species are harvested, as is the case in La Tirimbina, in Northern Costa Rica, where 36 different species are considered commercial species (Manta 1988). By contrast, in Nicaragua, with 18.2% forest cover, many species are not yet considered commercial, as is the case with "gavilan" (Pentaclethra macroloba) and "almendro" (Dipteryx panamensis). An extreme example is the vast forests of the Petén, Guatemala, where until recently, only two species were extracted in logging operations: Cedrela odorata and Swietenia macrophylla.

Lack of an integrated forest industry

Another characteristic of harvesting is the lack of proper integration between the logging operations and the timber industry. The forest industry in the majority of cases is not directly linked to logging operations, but rather hires out these services through third parties (informal loggers). For this reason, the industry has had little incentive to concern itself in how timber harvests are carried out, despite the fact that in the long-term, their interests will be adversely affected by a reduction of the forest cover.

Obsolete and under-utilized equipment

Mechanized logging with tractors and skidders is used throughout Central America. However, the majority of the machinery is obsolete and under-utilized, thus elevating operational costs and causing greater environmental damage. Oxen, on the other hand, are now seldom utilized for skidding, only by rural communities involved in forest management and by small independent loggers. While this method may appear antiquated, it is in fact a good example of appropriate technology, reducing cost and decreasing environmental impacts.

Excessive wood volume wastage

The large number of logs left unextracted is another characteristic of traditional timber harvests. Because loggers usually pay taxes on the wood volume extracted and not on standing volume, they only take the largest logs without defects. Large limbs of commercial volume are not utilized nor are logs with small cavities. Loggers are financially motivated to extract only the best logs in the shortest time, and normally leave over 20% of the cut wood volume unextracted.


In the process of forest management, operations relating to timber harvesting require great care and call for prudent planning and execution. In order for success, annual operating plans must be written to specifically cover each activity to be undertaken.

This chapter describes management operations undertaken by CATIE in its experimental forests that relate exclusively to low impact timber harvesting. Given the complexity of this subject, no reference will be made to multiple-use management, even though this is also a management objective in many of the experimental sites.

Technical and Operational Framework

Low impact harvesting techniques have been implemented by CATIE in various sites, from secondary to highly degraded primary forests. These forests do not serve just for developing and validating silvicultural techniques, but also for extension and demonstration purposes. This network of research and demonstration areas is located in the following Central American countries: Costa Rica, Guatemala, Nicaragua and Panama. Demonstration areas located in Honduras will be added in 1996.

The technical framework that constitutes a series of aspects involved in low-impact harvesting can be broken down in the following three phases: pre-harvesting; harvesting; and post-harvesting. The following activities are included in each of these phases:




Pre-harvesting activities

Preliminary forest inventory of the management unit. This type of inventory is normally carried out to provide information for developing or revising a general management plan. The overall goal is to quantify and qualify the tree population, specifically the distribution of abundance, basal area, and volume by diameter class and commercial groups on a per hectare basis.

The inventory plots are laid out randomly or systematically (with or without stratification). Sampling intensity is usually calculated so that the sampling error is no greater than 20% of the true mean wood volume. In Costa Rica, with forest patches averaging between 50 to 100 ha, sampling intensity is usually greater than or equal to 5% of the inventory area and the normal plot size is 0.3 ha (100 x 30 m). Normally, trees greater than 30 cm dbh are sampled using this percentage, with subsampling down to 10 cm dbh at a 2% intensity.

In summary, this type of inventory gives an overall idea of the potential for timber management in a given area, and provides information on how and when to carry out management activities in different areas of the sampled forest.

General management plan. The general management plan, which comprises the whole management unit, is not only written from a technical viewpoint, but also with an administrative, political, and social perspective in mind.

The technical aspects will obviously take up the majority of the plan, and focus on the presentation of detailed maps showing the annual cutting compartments, and protection areas where timber harvesting will not be permitted. Also illustrated in the general management plan are wood volumes to be harvested, species and minimum cut diameters, growth estimations, cut cycles, and a calendar of activities.

Management plans in Central America have traditionally been documents that are extremely long, costly, and written not as a guide for the property owner, but rather as a bureaucratic necessity to obtain logging permits (Sabogal et al. 1995).

CATIE, with financial support from the Central American Forest Action Plan (PAF-CA) and the World Wildlife Fund (WWF), organized an initiative to simplify management plans throughout Central America for broadleaf forests. Through a regional workshop and in consultation with different projects and institutions, a guide was developed for management plans (CATIE 1994). This has since been amended and approved by the Costa Rican Forest Service (Mirenem 1994), and is pending approval in the other Central American countries. The guide consists of the following components:

Planning inventory of the harvesting unit. This component, also called commercial census, is essential in order to write the annual operational plan and is a 100% inventory of all harvestable trees in the logging compartment. It was first applied by CATIE in 1990 (Quirós and Finegan 1994) and adopted in Costa Rica in 1992 (Mirenem 1991).

The commercial census is conducted walking throughout the proposed harvesting unit, marking commercial species over the determined minimum cut diameter. In order to find and mark the harvestable trees more efficiently, the logging compartment is divided into strips or small blocks, usually with a width between 50 and 100 m depending on topography.

The execution of this type of inventory is divided into two main steps: indication of commercial volume, and site mapping.

In the first step, for every harvestable tree in the logging compartment, the dbh, commercial height, natural lean direction, and location is indicated on standardized forms. Also noted is the grade of difficulty in extracting each tree, and the presence of precommercial-sized trees and vines around each harvestable tree.

In the second step, detailed maps of the harvesting unit that illustrate topographic and hydrologic features are essential in low-impact harvesting. The information needed to generate these types of maps is recorded at the same time as the planning inventory (commercial census). The base map should show contour lines, harvestable trees, and rivers and creeks. With this map, a well-planned low-impact harvest is possible that would exclude both steep areas and water courses (protection areas), and establish skid trails and logging decks so that erosion is minimized.

The cost of carrying out this sort of inventory in La Tirimbina, Costa Rica, was US$ 27.00/ha (Quirós and Reiche in press). This inventory has become a very useful tool for the success of forest harvesting operations.

The map below displays the distribution of all commercial trees greater than 60 cm  dbh, rivers and creeks, and proposed forest roads. Such a map significantly increases the efficiency in locating the trees to be harvested as well as those to be left as reserve.

Harvesting plan. The harvesting plan or annual operational plan proposed by CATIE has been put into a guide that specifically states the harvesting operations that need to be carried out in a given year, including maps and charts. In order that these operational plans truly serve as a guide to activities for the person who is going to implement the harvesting operations, they must be as simple as possible, avoiding technical jargon.

Detailed maps of the areas to be harvested and protected are key elements, clearly showing where logging, road building, and/or other activities are to take place on the property. At this time, decisions are made regarding the selection and location of all commercial trees to be harvested (including recommended direction of fall), seed trees, trees of endangered species, trees that are recognized as being important for wildlife, as well as reserve trees for future harvests. This plan should also state how the logs will be skidded, loaded, and transported.

Another objective of the operational plan is to assure that the recommendations made in the management plan relating to productive sustainability are carried out. Essentially, this means that the annual plan should include directions that are easily understood in the field on how many trees (or volume) can be cut in each compartment and guidelines for reducing operational costs and the impact on the vegetation and wildlife, soil, and rivers and creeks.

Workforce training. Before beginning the logging operations, a simple training plan is drawn up for personnel without adequate experience. The objective is to present rational reasons under field conditions for applying low-impact harvesting techniques, as well as the different directional felling and soil erosion prevention techniques, equipment maintenance and first aid.

Harvesting Activities

Construction of forest roads

Wherever possible, previously built roads should be renovated along with the construction of any new roads. The road system should consider the topography and concentrations of trees to be extracted. Maximum skidding distances with the equipment to be used should also be taken into account in road layout. The road layout should also consider minimum slopes, in order to reduce costs and damage to the forest. It should avoid crossing fragile areas, such as rivers and creeks, and unstable soils. The size and power of the equipment should be compatible with the needs for each particular operation, so that costs and damage to the forest are reduced.

The road system can be built on a temporary or more permanent basis, depending mainly on the potential for future timber harvests, and the long term management objectives. Temporary roads are built where the present harvestable volume will not pay the added costs associated with a permanent road system.

The logging road system that has been proposed comprises the following elements.

Primary forest roads. Permit heavy trucks all-weather access to logging decks. In some cases a gravel layer 30-40 cm thick is laid on these roads. In all cases roadside ditches are built and a full-bench design is used. Cross-drains are distributed according to the slope. A 3% minimum and 20 to 25% maximum slope are recommended to avoid excessive erosion. A 3 m width has been used in these types of road. Because of the extra costs associated with these roads, they are maintained and of a permanent nature. The total cost of these types of permanent roads with 30-40 cm thick gravel layer in Villa Mills, Costa Rica was US$ 10.00/m.

Secondary forest roads. Provide skidders and tractors access to the forest, and are not usually of an all-weather design (limited to the dry season). A full-bench design is also used and cross-drains are built into the steeper sections of these roads to control excessive erosion. The maximum slope recommended has depended on the equipment capability (skidder or tractor) and the characteristics of the terrain. The width of these roads has been 2.5 m. The total cost of construction of these types of road in La Tirimbina, Costa Rica was US$ 0.50/m (Quirós and Reiche in press).

Skid trails. Are designed in such a way as to minimize the skidding distance to the secondary roads or logging decks and usually run parallel with contour lines. The distribution of the skid trails should take into account the length of the cable used with the winch and also avoid the tractor or skidder leaving the skid trail. A 2.5 m width has been used. Simple roadside channels are built in order to reduce run-off. The use of these trails is restricted to the dry season and road cuts and fills are avoided.

Given the fact that road construction is the primary cause of erosion, and the main culprit in damaging the residual stand, the overall goal should be to try and maximize the area covered with the least amount of road distance.

In Central America, forest road construction has received little attention, partly due to the propensity for maximizing profits in the short-term.

Directional tree felling

Utilizing the base map with the trees to be harvested clearly marked, the tree fellers do not have to spend valuable time searching for these trees. This is especially important where the harvestable trees are isolated from each other (eg. Petén, Guatemala). Directional tree felling encompasses a series of preliminary steps:

The objectives of directional tree felling are based on the following criteria.

Protection of the residual stand. The main emphasis is to minimize damage to the surrounding vegetation, particularly the remaining commercially valuable trees. Also, large tree felling gaps and trees falling in water sources should be avoided.

Ease of log extraction. Where possible, trees should be felled to facilitate skidding, positioning the logs at 30º to 60º angles to the skids trails. This process will also minimize damage to the remaining trees and vegetation in general.

Product protection. This entails the use of special cuts in order to avoid trees falling in difficult terrain conditions or on any kind of impediments that could result in wood splitting and cracking, or the improbability of extraction.

Operator security. Care is taken to minimize risks and tree fellers should be informed of the whereabouts of all personnel and designated escape routes.

In some cases, wedges are needed to correct the direction of the tree fall. In an experimental forest dominated by high volume oaks (Quercus copeyensis and Quercus costaricensis), CATIE is testing five different directional tree felling methods. One of these methods uses cables and manual winches to control the direction of tree felling. However, this method has been necessary in only 1% of the cases.

Before the felling operation takes place, and preferably at least six months in advance, the vines attached to the harvestable tree are cut, usually with a machete.

Measurements of total damage (recoverable and irrecoverable) to the residual forest expressed in terms of percentage of the basal area, in the experimental oak forest of Villa Mills and the experimental lowland forest of La Tirimbina, were 5.9% and 4.9%, respectively (Beek et al. 1992). This damage is much lower than the damage resulting from traditional harvesting operations in the region (usually 30-40%).


Mechanized skidding comprises two phases: 1) from the stump to the skid trail, and 2) from the skid trail to the log deck. This first step has been performed with bulldozers using a 30 to 50 m cable with winch. The length of the cable has been increased up to 70 m using a cable extension.

This gives the following advantages:

In the second phase of the skidding operation, agricultural tractors or ideally skidders should be used and not bulldozers, as are often used in the region. Bulldozers are not recommended because of their slowness, thus increasing turn-around time. Also, because of their weight and lack of manoeuvrability, these machines tend to have a more negative impact on the site than lighter, more manoeuvrable skidders or tractors.

In small-scale operations and where there is low volume per hectare, the lower cost option of skidding with animals (oxen, horses, or water buffalo) should be considered.

Bucking, loading, and transport operations

On the log deck, the skidded logs are cut into lengths acceptable by the industry and also according to their transportability. To facilitate loading, a ramp is usually constructed so that logs can easily be pushed onto the truck bed. Mechanical log loaders are rare in the region.

In order to maximize wood yield in terms of acceptance in the market, the logs have been sometimes bucked starting at the small diameter end, measuring and bucking toward the larger diameter.


To assure that the recommendations and established guidelines made in the management and operational plans are followed, a registered forester ("regent forester") should be on site during the majority of the tree harvesting operation. Decisions about modifications needed to the operational plan are made by this person.

Post-Harvesting Activities

Harvest of residual logs

After timber harvest, many logs are left unextracted due to difficult access or because they are split, twisted or are small-size logs. This residual wood can present additional yields for a small-scale operation. In many areas, these unextracted logs are sawn on-site with chainsaws and saw guides, with the products being used for home-consumption or sold on the local market. Quirós and Finegan (1994) estimated for a harvesting operation in La Tirimbina, Costa Rica, that a volume equivalent to 20% of the extracted wood volume came from these kinds of residual logs that were sawn on-site. Other measurements in Corinto, Costa Rica, showed that this figure could be as high as 25% of the extracted wood volume.

Maintenance operations

In the final phase of low-impact timber harvesting, the forest roads that will not be used again in the near future are closed off to avoid erosion, whilst those that will be used in the near future for management or protection of the forest are kept in good condition, paying special attention to drainage. Fences are repaired, tree crowns are removed from any streams or rivers, and any inorganic materials, such as oil cans, fuel containers and other man-made debris left at the harvest site are also removed. These activities are carried out either during or after the harvesting operations.


Managing sustainably natural forests in Central America has become a more complex and more demanding discipline, making it essential to design and implement environmentally sound and cost-effective forest harvesting operations. These operations are the first and most important step towards sustainable natural forest management in the region.

In Central America, particularly on private lands, cost-effective and environmentally sound harvesting operations are crucial for reducing the conversion of forest lands to other land uses. By reducing the rate of land use change, the forestry sector is making a great contribution towards the conservation of biodiversity in the region.

The elements that are essential for low-impact forest harvesting systems are: comprehensive harvest planning; effective implementation and supervision of harvesting operations; careful post-harvest assessment; and development of a competent workforce.

The development of low-impact forest harvesting operations is very recent in the region. In this respect, the process that CATIE is promoting for the design and implementation of the guide for management plans, constitutes an excellent means for the transference of low-impact harvesting technology.

The type of environmentally sound harvesting operations described in this paper are being gradually adopted by forest owners and loggers, since their implementation has not resulted in higher costs for forest management operations and has improved the condition of the remaining forest.

In Central America, forest road construction has received little attention, partly due to the propensity of the logger to maximize profits in the short-term and to the lack of adequate knowledge among professional foresters. More attention should be given to this aspect.

Better criteria are needed for the selection of reserve trees, including ecological and production aspects.

The limited development of the forest industry sector in the region in terms of the small number of species processed, restrictions in log dimensions and limited development of timber uses, has become an important disincentive for the development of better harvesting operations. Low timber prices and high transport costs also have a negative effect on the sustainability of the management of natural forests in Central America.

The development of effective forest harvesting systems in Central America must consider the multiresource character of the broadleaf natural forests. In this respect, the harvesting techniques of non-timber forest products (NTFP) that are being developed by CATIE should be included in a code of forest harvesting practice for the region.


Beek, R. aus der., Quiros, D., y Stadtmüller, T., 1992: Principios, experiencias y resultados de aprovechamiento forestal controlado en dos tipos de bosque tropical con énfasis en la reducción de daños al rodal remanente. Memorias del Foro Internacional sobre los Aprovechamientos Forestales en Selvas y su Relación con el Ambiente. Chetumal, Quintana Roo, México. pp. 2-5.

CATIE, 1994: Modelo de simplificación de planes de manejo para bosques naturales latifoliados en la región de Centroamérica. Turrialba, Costa Rica. 29 p. + anexes.

CIFOR, 1995: A way forward to sustainable development. Forest Research. Jakarta, Indonesia. 28 p.

Dykstra, D. P. and R. Heirnrich, 1995: FAO model code of forest harvesting practice. FAO, Rome. Forest Harvesting and Transport Branch. Forestry Department. 105 p.

Manta, M. I., 1988: Análisis silvicultural de dos tipos de bosque húmedo de bajura en la Vertiente Atlántica de Costa Rica. Tesis Mag. Sc. CATIE, Turrialba, Costa Rica. 150 p.

Ministerio de Recursos Naturales, Energía y Minas., 1991: Guía para la elaboración de planes de manejo y estudios de capacidad de uso de la tierra. Dirección General Forestal. San José, Costa Rica. 25 p.

Ministerio de Recursos Naturales, Energía y Minas., 1994: Guía para la elaboración de planes de manejo y estudios de capacidad de uso de la tierra. Dirección General Forestal. San José, Costa Rica. 98 p.

Pedroni, L., y Flores, R., 1992: Diagnóstico forestal regional para Centro América y propuestas de trabajo. Informe de Intercooperation y UICN/ORCA. San José, Costa Rica. 92 p. + anexes.

Quirós, D., y Finegan, B., 1994: El manejo sustentable de un bosque natural tropical en Costa Rica: definición de un plan operacional y resultados de su operación. Serie Técnica. Informe Técnico no.225. Colección Silvicultura y Manejo de Bosques Naturales no. 9. CATIE, Turrialba, Costa Rica. 30 p.

Quirós, D., y Reiche, C., Análisis financiero de un modelo de manejo sustentable para un bosque natural tropical en Costa Rica. Serie Técnica. Informe Técnico no.__. Colección Silvicultura y Manejo de Bosques Naturales no.__. CATIE, Turrialba, Costa Rica. (in press)

Sabogal, C., Martins, P., y Flores, J., 1995: Planes simplificados de manejo forestal: una propuesta para los bosques latifoliados de América Central. Revista Forestal Centroamericana (Costa Rica), 10, pp 27-32.

Research and Monitoring for Sustainable Forest Management in North-West Guyana


C.J. Inglis, G. Sutton and G.J. Lawson

Edinburgh Centre for Tropical Forests

Edinburgh, Scotland


The Barama Company Limited (BCL), a joint venture between South Korean and Malaysian investors, signed a contract in 1991 with the Government of Guyana under which BCL was granted a timber concession of 1.7 million ha. The concession was granted for 25 years with an option to extend for a further 25 years. BCL has built a plywood mill outside Georgetown, which currently has 4 lines operational, but plans to construct a total of 12 lines , making it the largest plywood mill in South America. It has been the policy of BCL from the outset to manage its forest concession sustainably. The company recognised the need to have a research and monitoring programme carried out independently of its operational activities, to ensure that all possible precautions are taken to safeguard the environment from avoidable damage.

BCL retained the services of the Edinburgh Centre for Tropical Forests (ECTF) in 1992 to undertake a programme of monitoring and research. The primary objective of the project is to carry out independent monitoring of the activities of BCL against a series of environmental criteria and to conduct a research programme which will inform the forest management plan and assist the company to fulfil its objective of: "ensuring the sustainability of the forest in perpetuity whilst selectively harvesting a major natural resource for the benefit of the company, people and Government of Guyana".

It is rather early to provide firm conclusions on the sustainability of the company's activities, but this paper describes the impact assessments, monitoring, research and training activities which are being undertaken by ECTF. Most emphasis has so-far been placed on monitoring the effects of BCL's current logging practices on tree cover and composition. Research plots on modified logging techniques have been established, but development of this part of the programme is anticipated for the future.


The BCL concession is located in the north-west of Guyana (Figure 1), in an area which is remote from centres of population and can only be accessed by air or river.

The Physical Environment

The concession is almost entirely underlain by the pre-Cambrian plateau of the Guiana Shield. The major geological formations in the concession are granite and greenstone. The soils in the northern part of the concession are acid clays of low fertility. Three major rivers dissect the area: the Barima and Barama draining to the north in Venezuela, and the Cuyuni draining centrally into the Essequibo River. All rivers and streams drain into these, except for small watersheds draining into the Kaituma River on the northern concession boundary, and into the Puruni River on the southern concession boundary.

The concession is predominantly flat or undulating lowland without major topographic features except in the west. On the eastern fringes of the concession there are some patches of coastal swamp and towards the south-east there are patches of white sand. Most of the concession is dry land with intermixed marsh forest and riverine flood plain. The western parts are more hilly but nowhere does the topography exceed 240 m.

The climate of the area is fairly typical for lowland rain forest, with an annual rainfall in the northern part of the concession of 2,400 mm. It rains during every month with rainfall peaks in June-July and December-January, during these periods average monthly rainfall exceeds 300 mm. The driest period is March-April with average monthly rainfall of 90 mm. Mean temperatures range between 23 and 32_C and relative humidity is between 83 and 97%.

Figure 1. Location of the BCL concession in northwest Guyana

The Forest Environment

Guyana is 75% forested (over 16 m ha) of which 3.6 m ha is currently accessible for timber production. Timber volumes are typically around 180-220 m3 ha-1 (all species), with 100-150 m3 ha-1 of "commercial" species (FAO 1970). Greenheart (Chlorocardium rodiei) is the dominant commercial species, comprising 1.5% of total timber volume, 40% of timber harvested, and 70% of timber exported. Mean stocking density for the mixed forest is 25 commercial trees ha-1 out of a total stock of 75-100 trees ha-1 (>20 cm dbh).

The concession area is almost entirely forested apart from modest areas which have been cleared for mining and past agricultural development. No forest inventories have previously been undertaken in the concession area, nor has any research taken place on the impacts of logging.

Greenheart is largely absent from the BCL concession, as are several other timber species from central Guyana like Wallaba (Eperua sp.), Morabukea (Mora gongrijpii) and Wamara (Swartzia leiocalycinai). Forest types in NW District are dominated by "mixed dryland forest" (Table 1), although the BCL inventory suggests a higher proportion of seasonally flooded (20%) than previously thought.

Table 1: Proportions of forest types in the North-West Region (Welch 1975)

Mixed forest on undulating or hilly terrain

Mixed forest on deeply dissected terrain

Mora forest on flat, seasonally flooded riverine terrain

Mixed forest on steep hills

Wallaba forest on white sands ridges

Mixed forest on flat terrain along rivers







BCL has undertaken an inventory of merchantable timber in the NW part of the concession, this was initially a 100% sample (Table 2), but is now 20%. The initial inventory counted only undeformed stems of commercial species with diameters over 35 cm. This showed the commercial volume to be around 34 m3 ha-1, with 70% in plywood or potential plywood species. The size frequency distribution (Figure 2) is heavily skewed towards the smaller age classes. Baromalli and Crabwood occur in highest densities in dry forest, and white Cedar (Tabebuia insignis) and Mani (Symphonia globulifera) in marsh forest. Few trees have diameters exceeding 100 cm, and they have a lower stature than in other parts of Guyana.

Guyana has 72 species of endemic higher plant species (GAHEF 1992), and 10 endemic amphibians and reptiles. 144 Guyanian animals and plants are listed in CITES (Convention on International Trade in Endangered Species) No measurements of biodiversity have been made in or near the concession, although an ethnobotanical survey has identified plants of use to man and certain animal groups (Adams 1972).