Chapter 2 Harvest planning
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Potential consequences of inadequate planning
What it is
Planning of timber harvests is one part of overall forest management planning, which is itself a component of comprehensive land-use planning.
Harvest plans are of two types: strategic and tactical. The
strategic harvest plan, prepared by the forest planning team, is
a long-term plan that answers the following questions for the
forest or concession area as a whole:
- what type of harvesting must be done;
- why it must be done;
- where it must be done;
- when it should be done.
The strategic harvest plan should demarcate non-harvest areas, divide the harvestable forest into annual operating areas (coupes) and design the main transportation system.
The tactical harvest plan, prepared by the team directly
responsible for supervision of harvesting operations, is a
short-term plan that answers the following questions for each
- how the harvesting is to be done, in detail;
- who will carry out the operations;
- when each part of the coupe should be harvested.
Forest harvesting operations are most likely to meet economic, silvicultural, environmental and social objectives if they are carried out as outlined in a properly prepared harvest plan.
Before harvest planning is initiated, a comprehensive land-use plan should be completed to identify the permanent forest estate and the portions of this estate on which timber harvesting will be permitted. Areas where forest plantations will be established should be identified and quantified. The land-use plan should also show areas of forest, if any, from which the trees are to be removed so that the land can be used for other purposes such as agriculture. Commercial timber harvesting is normally permitted in these areas of conversion forest, but it must be recognized that such harvesting is inherently unsustainable. This model code of practice does not explicitly consider harvesting in conversion forests, although practices similar to those recommended in these guidelines would be appropriate in such situations in order to best preserve the environment during the conversion process.
An essential requirement for strategic harvest planning is the development of a comprehensive forest management plan. It is important to remember that harvest planning by itself is not forest planning; the harvest plan is only one part of a complete forest management plan. It is unquestionably an important part, however, since harvesting generates revenues and provides an opportunity to modify the forest so that it can contribute most effectively to economic, social and environmental objectives. But harvest planning cannot be done in isolation from forest planning; the two are complementary and should be undertaken simultaneously by an interdisciplinary planning team that includes foresters, ecologists, logging specialists, engineers, wildlife biologists and other individuals representing specialities in the social sciences.
Comprehensive harvest planning is essential in order to set the stage properly to enable sustainable harvesting practices to be followed, and also to reconcile the need for greater technical control during harvesting with the need to reduce harvesting costs simultaneously. Many logging operators believe that environmental protection can only be achieved through costly measures that will drive them to the brink of bankruptcy. This is simply not true. The experience of operators who develop thorough harvest plans and then carry out the operations as specified in these plans has demonstrated clearly that these procedures not only improve operational control and reduce environmental impacts, but can also reduce costs and substantially increase profits.
Effective planning is one of the most essential requirements for successful, environmentally sound forest harvesting.
Strategic and tactical harvest plans should specify ways of:
- optimizing harvesting production rates;
- minimizing environmental and other impacts associated with harvesting operations;
- accommodating the needs and wishes of local communities and indigenous peoples and making provisions for their participation in making decisions about harvesting operations and in benefiting financially and economically from those operations;
- providing efficient access to the forest for silvicultural, protection and transport purposes;
- minimizing harvesting and transport costs, subject to constraints imposed by environmental, ecological and social considerations;
- identifying opportunities to coordinate timber harvesting with the collection of non-timber forest products;
- avoiding scheduling problems;
- providing for flexibility so that the plans can be changed to take advantage of new information or changing situations;
- protecting the health and safety of workers and the public.
Potential consequences of inadequate planning
Far too many harvesting operations are carried out without the benefit of any kind of formal, written plan. Such operations are difficult to coordinate, impossible to control adequately and in their effects often more closely resemble mining operations than harvesting operations designed for the sustainable utilization of forest products.
Even where harvest plans are required, often only a tactical plan is prepared. This means that the transportation system is developed in a piecemeal way, with roads being planned separately for each coupe rather than a system being designed for the entire forest with roads being constructed when access to an individual coupe is required. Consequently, far more forest area than is necessary is cleared to build roads, resulting in accelerated soil erosion, increased stream sedimentation and higher costs of road construction, maintenance and transportation.
Lack of adequate harvest plans may also result in scheduling problems that greatly increase disruptions and force logging supervisors to manage from crisis to crisis rather than being able to carry out operations in a systematic, organized way.
This type of harvest planning cannot be separated from management planning, as both must be done simultaneously by an interdisciplinary planning team.
A map and a written plan are elements of a good strategic harvest plan. The map, typically drawn to a scale between 1:10 000 and 1:50000, should show the following features as identified in the forest management plan:
- forest cover types, important topographic features
(preferably with elevation contour lines), streams and both
existing and planned infrastructure or other artificial features;
- protection areas such as biological reserves, religious or cultural sites or areas near population centres;
- areas where harvesting is to be carried out, divided into annual coupes or similar areas that can be conveniently referenced on the ground;
- areas where major problems exist that must be overcome when developing the transportation system or in carrying out the harvesting operations. These would include rock outcrops, swamps or other areas of wet soils, important stream crossings and other features;
- areas of non-forest land uses;
- locations of communities or indigenous populations that could be affected by harvesting or transport operations.
The written plan should describe in detail the items shown on
the map. This plan would typically include the following:
- a description of the planned silvicultural treatment (e.g. individual-tree and group selection, shelterwood and clear-felling) for each harvesting coupe and an explanation as to why each treatment has been selected, including an analysis of the degree to which harvesting is expected to contribute to the attainment of management objectives for the forest;
- a description of the types of harvesting equipment to be used in each coupe (for example, 20 percent of the area to be extracted with cable systems, 60 percent with rubber-tyred skidders, 5 percent with draught animals and 15 percent with helicopters), with an explanation of the selection criteria employed;
- an estimate, based on a proper inventory, of the volume of timber to be removed from each coupe, preferably divided into species or groups of similar species;
- a schedule showing the year in which each coupe is to be harvested;
- descriptions of any special problem areas noted on the map, with suggestions for overcoming the problems;
- a discussion of potential problems relating to local communities or indigenous populations and the way these problems have been addressed in formulating the plan;
- detailed information concerning the forest transportation system, such as road design parameters for different conditions (valley bottoms, ridgetops and climbing roads), locations and specifications for major stream crossings, typical spacing and design specifications for drainage structures and other similar information;
- annual labour requirements for harvesting operations and for construction and maintenance of the forest transportation system;
- provisions for living quarters and other facilities needed to accommodate forest workers, together with general information on health and safety provisions;
- the estimated cost of harvesting operations in each coupe and of construction and annual maintenance of the forest transportation system.
Short-term tactical plans normally provide details of operations that are to be carried out during a period of one year or some other convenient unit of time, such as a dry season. Thus, a tactical plan is associated with the annual coupe. Sometimes, however, a coupe is not a single, contiguous block, but instead the areas to be harvested within a year are dispersed throughout several separate regions of the forest. The nature of the coupe largely depends upon the type of forest, its stage of maturity and the administrative preferences of the agency responsible for forest management.
The tactical plan, like the strategic plan, should include a written description of the planned operations as well as a detailed, accurately scaled map. The plan should be consistent with environmentally sound harvesting practices such as those recommended in Chapters 3 to 7 of this model code of practice. The following steps are recommended for the development of tactical harvest plans:
- A topographic survey should be conducted, either on the ground or by using low-altitude aerial photography with ground checking, and a large-scale topographic map prepared. The best maps for detailed harvest planning are usually drawn at scales between 1:2 000 and 1:10 000, depending upon the topographical irregularities and the types of harvesting equipment to be used. In some areas, maps with scales as small as 1:20 000 are used for tactical harvest planning, but this scale provides less detail than is desirable for satisfactory planning.
The contour interval selected for the topographic map will depend upon the topographical irregularities and the relationship between the costs of mapping and those of harvest planning errors. In general, additional money spent on preparing good maps will pay off in reduced harvesting and infrastructure costs. A contour interval of 5 m or less usually provides satisfactory detail for planning, as long as the contour lines accurately represent the ground surface.
The topographic map should accurately show the boundaries of the harvest area and the location of water courses, swamps or other areas of wet soils, gullies, rock outcrops, sites of religious or cultural significance and any other feature that may influence harvest planning.
- The annual coupe should be divided into administrative units that can be identified on the ground and used to help control and guide the operation. If these units, referred to here as "cutting units", are contiguous, then planning should be done for all of the units simultaneously. If they are dispersed, then individual plans may need to be developed for each cutting unit or group of cutting units.
An individual cutting unit should be limited to a single extraction method. This is because the planning of harvesting operations for cable systems is significantly different from that for ground-skidding machines or forwarders, and different again from that for skidding with draught animals or extraction with aerial systems such as helicopters. For administrative purposes, operations that use different extraction methods should therefore be allocated to different cutting units.
- On the topographic map, streamside buffer zones should be delineated as well as other special management areas in which cutting is either to be prohibited altogether or will be subject to special restrictions. These might include areas of significant scientific, recreational, cultural or aesthetic value, special reserves for wildlife or for the production of non-timber forest products, water catchments, areas of saturated soils and erosion-prone sites.
- Using the topographic map as a guide, an inventory of the trees in the operating area should be conducted to estimate the timber volume and its distribution over the cutting unit, as well as the number and condition of potential crop trees that are currently immature and should be protected to form a future crop. The kind of inventory needed for this purpose will depend upon the type of forest and the cost of carrying out the inventory. In temperate forests, a sampling inventory is usually sufficient, as the volume to be harvested from each hectare is relatively high and the trees are reasonably uniform in size; it is not necessary for planning purposes to know the location of each individual tree to be harvested. In the mixed broad-leaved forests of the tropics, the volume harvested per hectare is typically quite low, although the value of an individual tree can be substantial. In such forests it is now generally considered essential to make a complete inventory of all trees that might be harvestable. Each tree should be identified and numbered, its diameter should be measured and the commercial stem quality assessed. If standard volume equations are used, the tree's height should also be measured. These data should be recorded on inventory sheets and the tree's location should be marked accurately on the topographic map.
Part of 1:5000 tactical planning map for a harvesting operation in a tropical forest. The circles indicate trees to be felled, and the arrows show the planned felling direction. Heavy dashed lines represent skid trails, and the two open rectangles are landings. Such a map can be taken into the field when marking trees for felling and laying out skid trails, and later it can also be used by the felling and extraction crews. After the operation has been completed, the map will be useful in post-harvest assessment to compare the actual layout with that specified in the harvest plan.
-The inventory data for the operating area should be tallied, and, for selection harvesting, the trees to be harvested must be determined. This will depend on such considerations as management goals, market acceptance, diameter limits, silvicultural guidelines, operating constraints and estimated harvesting cost.
- A detailed transportation and extraction system for the operation should be laid out, using the topographical map, with those trees to be harvested marked on it. Such a plan will include the haul roads that will connect to the main transportation system, the landings where logs will be concentrated during the extraction process and the skid trails (if ground-skidding systems are to be used) or cableways (if cable systems are to be used). This system must be laid out so that it efficiently accesses the trees to be harvested while accommodating the terrain, circumventing problem areas, avoiding streams and minimizing the total length of roads and skid trails. Where a stream cannot be avoided altogether, the site should be surveyed in the field and a stream crossing designed that will minimize environmental problems.
In steep terrain, it is often desirable to first locate potential landing sites and then see whether or not it is possible to reach them with roads. The full transportation system, including both roads and landings, thus becomes a matter of compromise between the optimal locations for landings and the reality of where it is environmentally, economically and physically possible to build roads.
- In tropical forests or other areas where planning involves decisions about individual trees, the approximate direction of fall for each tree to be harvested should be determined using the transportation plan as a guide. This direction should be marked on the map; it is to be verified in the field and changed if necessary when the tree is actually marked for felling'
-Specific harvesting equipment to be used should be determined and a preliminary operations schedule developed, using appropriate estimated production rates.
-The preliminary schedule must be modified as necessary to accommodate the timing of the normal onset of the rainy season. Contingency plans should be developed for severe storms and other extreme events. The time of seed fall must also be considered in areas where seed is not produced year-round, such as in many deciduous and semi-deciduous forests.
- Whether harvesting operations on some cutting units need to be scheduled to avoid breeding seasons of primates or other sensitive animals or the nesting seasons of rare or endangered bird species that may be present in the area needs to be determined.
- The possible complementarily of harvesting non-timber forest products should be considered (for example, cutting rattan or tapping resins prior to the timber harvest or collecting fuelwood after the harvest). If appropriate, these products should be included in the harvest plan.
- Local communities or indigenous peoples living near the harvesting site should be consulted about the planned harvesting operations, including any potential scheduling problems or opportunities (for instance, ready labour availability during slack agricultural periods).
- Relevant landowners or government authorities should be contacted about any right-of-way easements that might be needed before road building or other construction activities can be initiated.
- Before finalizing the harvesting plan, loggers should be consulted to ensure that the plan is feasible and that the operation can be undertaken safely, efficiently and economically.
- Copies of the harvesting plan and the accompanying topographic map showing the trees to be harvested and the transportation system must be given to the supervisor of the harvesting crew, who will be responsible for ensuring that the plan is carried out and that every member of the crew is familiar with the requirements and working procedures. A thorough understanding of what is to be done and the standard of work expected is perhaps the single most important requirement for a successful operation.
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