1 Implementation of forest management plans
2 Implementation of harvesting operations
3 Implementation of post harvest operations
4 Further reading
Neither the planning process, of itself, nor the approval of plans, will necessarily lead to the successful implementation of plans. Effective implementation depends upon a good level of understanding and acceptance by government officials, forest managers, forest workers, machinery operators, rural communities and others who will be involved in the task of implementation. No less importantly it also requires:
* A firm commitment to allocate funds, staff and other resources for the duration of a plan to enable prescriptions to be implemented.* An appropriate organization structure and the appointment of people having appropriate knowledge and experience for specific, well-defined positions that are relevant to plan implementation.
* Training to ensure that people appointed to all positions are up-to-date with procedures, techniques and practices.
* A commitment to regularly monitor progress in plan implementation and to amend annual programmes when necessary.
2.1 Reading
2.2 Training
2.3 Harvesting operations
2.4 Landing operations
2.5 Log measurement (scaling)
2.6 Transport operations
2.7 Harvesting assessment
The following guidelines are suggested for implementing harvesting operations. Reference has been made to the FAO Model Code of Forest Harvesting Practice in regard to principles and some aspects of forest harvesting practice. Readers should refer to the model code of practice for detailed explanations on forest road engineering, cutting, extraction, landing and transport operations and the forest harvesting workforce.
Forest roads are an important aspect of tropical forest management because of their high cost and the adverse environmental impacts that can be caused in respect of soil erosion and sedimentation of watercourses. If unregulated, forest roads provide access to people, leading to forest damage through slash and bum agriculture. Roads should be designed and built by engineers who understand the need to minimise soil disturbance, maintain proper drainage and avoid stream crossings. Tropical forest roads are usually classified into two groups - haul roads and feeder roads.
* Haul (or Arterial) Roads/Haul roads form the transportation network over which the logged harvest is transported from landings to a mill or to an intermediate shipping point, such as a log pond or transhipment yard. Haul roads are permanent, should have an all-weather running surface and should be sufficiently wide to enable two vehicles to safely pass. They are also used for other management purposes, such as protection and silviculture.* Feeder (or Secondary) Roads: Feeder roads are located in a cutting area and form the outer ends of the haul road network. They provide access for workers and machinery to the cutting area and reduce skidding and forwarding distances. Feeder roads are normally only temporary and are abandoned following logging.
The principles of forest road engineering that should be considered are:
* Roads should provide convenient low-cost access for the transport of logs and should also benefit forest communities.* Access to roads built through forest land where the management objectives are watershed and biodiversity conservation, wildlife or scenery protection, or the conservation of cultural or religious values should be strictly regulated.
* The total road length, grades and curves should be minimised in order to reduce the erosion potential of roads, to reduce needless deforestation and to cut road construction and maintenance costs. Road density will depend on the forest type, topography, the cost of road construction and maintenance and the cost of log extraction. In general, because of the generally low volume of harvestable logs per hectare in selectively managed tropical forests, the optimum road density is lower than where clearcutting is practised.
* Feeder road density is related to skidding distance as follows:
where:
D = feeder road density in km/ha
a = a "road efficiency" factor, usually between 5 and 9;4 - 5 for flat land,s = the average skidding distance in metres
5 - 7 for hilly land,
7 - 9 for steep terrain,
9 or more for very steep, rough terrain
This relationship can be used for estimating average skidding distance when the road density is known, or for estimating road density when average skidding distance is known. Details of optimum feeder roading spacing, road density and skidding distance relationships are explained with examples in Annex 4. Although common sense needs to be shown in the use of the feeder road/skidding relationship it is a useful working guide.
* Road construction should be consistent with good design and maintenance practices, minimising road and landing areas while providing adequate roadside clearings to permit roads to dry quickly after heavy rains.* Soil erosion associated with road construction and maintenance should be minimized, thereby reducing sedimentation in streams and damage to stream ecosystems. Minimise cutting and filling and utilise natural drainage patterns in road design.
* Roads and landings should be kept away from streams and from streamside buffer (protection) strips. Where a stream crossing is needed the crossing structure should be designed on the basis of a site survey. Minimise stream disturbance during construction.
* When culverts are used for cross-drains or stream crossings, their size and spacing should be determined by local rainfall intensity and water runoff rates.
* Where practicable, roads should only be built during dry season conditions and should be allowed to stabilise through the next rainy season. Roads must be allowed to dry out thoroughly before being used by heavy machinery.
* Where possible, avoid areas of wet soils and high erosion risk; roads are expensive to build and to maintain in such areas.
* As a general guide, the average forest road width should be restricted to the minimum that will allow log transport to be carried out efficiently and safely. This will reduce forest loss and the potential for soil erosion. As a guide, the maximum clearing width should not be more than 10 metres for major roads nor more than 8 metres for minor roads.
* Road grades should be kept as low as possible, consistent with the need to provide adequate access to a forest. Maximum grades of eight to 12 per cent are suggested, except for short lengths of road where steeper grades are needed to provide access to higher ground. A ruling gradient of five to eight per cent is suggested for main and secondary roads. Formulae for conversion of slopes between slope per cent, degrees and gradients are shown in Annex 8.
* Where practicable, avoid mixing horizontal and vertical curves during road line planning and construction.
* Good maintenance of road surfaces, roadside drains and culverts is needed to protect roads and to ensure that they can continue to be useable for post-harvest silviculture and for future log harvests.
* Feeder roads that are not expected to be used again until the next harvest cycle can be closed to prevent their use by local communities or others. Road closure can be achieved by ripping the surface and planting shrubs or grass.
All agencies involved with the management and harvesting of logs should make and implement arrangements for effective training of logging crews. The aim is to increase and maintain the professional skills, work performance, and work quality of workers, and to develop and maintain an awareness of social and environmental issues. In its simplest form, training can be "on-the-job" guidance on proper logging practices provided by supervisory personnel. It is also desirable that workers attend practical courses on safe harvesting practices. These should be repeated each year.
The following general training guidelines are suggested:
* All field personnel who are to be involved in log extraction that requires heavy machinery and suspended loads should be trained in the need for operational safety and working cooperatively as a team. Instruction should cover the need for an understanding of the role of each person in the team and their job and the need to practice good working methods.* Field and aircraft personnel to be involved with helicopter log extraction should be trained in operational safety involving aircraft and suspended loads, radio communication between personnel and the need to practise good working methods.
* Training in fire prevention and control should be mandatory at all levels of organisation so that all personnel, including rural communities, know their role in the event of a wildfire. It should be in the form of short courses and practical training exercises. People who have not received some training should not be allowed to fight forest fires. Topics should include:
· The safety of people and equipment, including the use of fire safety clothing,· The use of tractors, pumps, hoses and other equipment,. Methods of communication on a fireline,
· Simulated practical fire safety exercises to test that institutional arrangements, knowledge amongst personnel and equipment are able to cope with a forest fire emergency.
Pre-Felling Treatment
As road construction progresses ahead of cutting, it may be necessary to undertake pre-felling treatment within a felling area. Pre-felling treatment comprises cutting of the stems of large, climbing plants which have stems, branches and foliage in the forest canopy. The purpose is to cause climbers to die, allowing the stems to decay so they break during felling. Not to do so can lead to accidents during cutting and to tree damage because branches can be torn from residual trees. General pre-felling treatment guidelines are as follows:
* Climber Cutting: Climbers that bridge across the crowns of trees to be harvested or will influence the fall of a tree should be cut one to two years in advance of cutting. Depending upon the silvicultural system, climber cutting can be combined with cruising. It can be performed by a small crew of two or three who work systematically through forest where climbers have been noted during pre-harvest inventory. Climber stems are cut near the ground, using a bushknife, axe or powersaw.* Rattan: Rattan stems can be cut and extracted on a commercial basis by the concession holder if this is appropriate. Alternatively, extraction can be offered or contracted to local communities.
Cutting
Cutting includes all activities undertaken to fell and prepare trees for extraction, including felling a standing tree, measurement to determine best log lengths, limb removal and cross-cutting to form logs.
The following principles, practices and standards should be applied in cutting:
* Forest land and trees that are not shown in a harvest plan, or marked otherwise as trees not to be felled, should not be cut, and the felling operator should be aware of such disposition.
* Operations should be safe for workers and others in the vicinity. Good worker supervision and good worker health are essential. Appropriate safety equipment must be worn. Chainsaws and other equipment must be properly maintained.
* Cutting should be carried out by personnel who have been trained in the correct use of chainsaws and safety equipment, such as protective clothing, and trained to interpret labels on trees that indicate which trees should and should not be felled.
* Chainsaws or crosscut saws should be used for felling and for crosscutting to form logs. Axes should not be used because of the wastage of wood that occurs. Directional felling should be practised to reduce damage to residual trees, saplings and seedlings, especially those that are expected to become future crop trees.
* Only trees that have been labelled and numbered, for harvesting, at the stump and at "dbh" height should be cut. Cutting crews should be trained to recognise labelled harvest trees and be properly supervised to ensure that only these trees are cut. Cruising labels should remain on stumps for post-harvest monitoring. Trees that are labelled as being seed trees must not be cut or damaged during felling operations. Checks should be made on a logging landing and during post-harvest checking to monitor whether reserved trees have been cut.
* The identity of all trees that have been measured and labelled for harvesting (during cruising) should be maintained through to log formation. The following guidelines are suggested:
· A feller should carry a copy of cruising map showing the location and numbers of trees to be cut.. A cutter should remove each cruising label from the side of a fallen tree that has been cut and firmly attach it (using a flat-head nail) to the log butt.. The duplicate section of the label should be removed by the feller as a record of each tree that has been cut.· The duplicate section of each label should be handed to the harvesting crew supervisor at the end of each day for use later in a harvest assessment of the cutting area. A record of the tree numbers cut each day should be maintained by the harvesting crew supervisor. This is a practical monitoring requirement to ensure that only trees labelled for cutting (the "compulsories"), are in fact cut.
* Practical guidelines for directional felling are:
· Cutting crews should be trained to carefully select the felling direction. On flat or slightly sloping land each tree to be cut should be felled either towards or away from skid trails or cableways, depending upon local experience, topography and the type of logging system being used. Directional felling simplifies log extraction and markedly reduces forest damage and overall logging costs.· Trees should not be felled directly down steep slopes unless the downhill lean is so great that directional felling is unable to pull the tree in another direction. Felling across a slope or along a contour, will reduce the momentum of a falling tree and minimise breakage and damage to nearby trees.
· Where possible, trees should be felled in the direction of canopy gaps and alongside skid trails to reduce forest damage.
· It is desirable to direct the fall of a tree towards the crown of previously felled trees. This reduces both impact damage and damage to surrounding forest.
· Trees that are too difficult, too dangerous or that upon felling would cause too much damage to the remaining vegetation, should not be cut at all.
· The same applies for rare tree species or that are found few in numbers in the area to be harvested.
· The final assessment and decision on whether or not to fell a tree should always be made by the cutter.
* Tree felling should cause minimal damage to soils and watercourses. Trees should not be felled across streams where there is no streamside protection strip in order to minimise damage to the watercourse, to streambanks and to vegetation. National or local regulations concerning streamside conservation should be observed.
* Operations should maximise the volume of wood that can be profitably utilized from each felled tree and maximise the value of logs that can be prepared for extraction. Cutting crews should be trained to follow proper log making procedures. The whole tree should be measured prior to crosscutting and log lengths determined according to market or mill requirements.
* Log formation involving the cutting of branches should take place within the forest in order that nutrients in foliage can be retained within the forest ecosystem. Branches should not be removed from a forest. This practice also reduces damage to the soil and to the remaining vegetation.
* Penalties should be imposed on felling crews for careless working practices that lead to cutting or damage of future crop trees or those reserved as seed trees. Penalty arrangements should be included in management contracts that are specific to the local situation. Frequent operational monitoring is necessary in order to detect cutting damage and to identify who caused it.
Extraction
The choice of extraction method and equipment selection will depend on topography, soils and climate, tree size, number and volume, the silvicultural system being applied as a basis for sustainable management of a forest and on the economics of the specific management and harvesting operation. The following guidelines for log extraction using different extraction systems should be adapted and applied to local forest situations:
· The safety of all personnel involved in log extraction is the foremost consideration in logging. Good training of logging crews is necessary to minimise accidents.· Minimise damage to residual trees, to other vegetation and to soils and watercourses. Select the type of log extraction system that will minimise soil compaction and soil disturbance and also minimise runoff of water and soil erosion.
· Thoughtful and comprehensive harvest planning linked to a system of operational control to ensure that a plan is followed and adapted as required in response to changing conditions.
· Delivery to a landing or roadside of all logs prepared for extraction without loss of tree identity and without significant loss of volume or deterioration in quality.
· Achievement and maintenance of high productivity in the use of personnel and equipment.
· Maximise wood production during extraction. Two effective steps are:
- Extraction of "forest residues" as an additional income source, especially for forest dependent communities,- Minimisation of logging waste through careful cutting, tree measurement and log formation.
Extraction must be continuously and closely supervised to ensure that safety and all technical aspects of a harvesting plan are being followed as proposed. In addition, animal skidding should be supervised to ensure that animals are not being abused.
· Ground Skidding Extraction:
· Wheeled Skidders: Wheeled skidders are the primary means of log extraction in sustainably managed tropical forests. Skidders are preferred to crawler tractors for ground extraction of logs because their rubber tyres, ability to easily manoeuvre within a forest and to lift log butts off the ground can minimise soil and tree damage. Skidders are specifically designed for log extraction and are more suitable for harvesting than are crawler tractors. They should have a powered winch. "High-flotation" tyres or dual wheels mounted on wheeled skidders increase the effective tyre width where they are in contact with the ground, thus spreading the machine weight and its load over a larger surface area, reducing pressure on the soil and reducing soil compaction and disturbance.· Tracked Skidders: Tracked skidders are preferred to wheeled skidders and crawler tractors, especially for extraction of small to medium sized logs on forest soils that are easily compacted, because they cause minimal damage to residual trees and soils. Tracked skidders have the ability to move the load forward onto the machine for better weight distribution over the tracks. Low ground pressures lead to relatively little disturbance of soils and ground vegetation, which is an important feature for protection of seedlings and saplings and for soil conservation.
· Crawler Tractors: Crawler tractors are often used for skidding as well as for road construction and maintenance. They have the advantage of being effective for log extraction from steep slopes if properly used, even if equipped with only a single drum winch. In spite of the damage that can be caused to soils, residual trees, poles, saplings and seedlings through insensitive use, crawler tractors are likely to continue to be important for log extraction in steep terrain and where rainfall is high. Effective training of operators and careful supervision is necessary.
· Size and Power of Skidders: Skidders of the appropriate size and power configuration for a specific operation should be selected. The blade width should be between two and three metres. Machines should have a powered winch, with at least 50 metres of wire rope, and an arch that will lift log butts clear of the ground. These features help to minimise damage to residual trees, ground vegetation and soils.
· Steep Slopes: Avoid steep slopes in ground skidding operations. As a general rule, the maximum slope should be about 30 per cent, except over short distances (less than 100 metres). Ground skidding on steep slopes greatly increases soil disturbance and erosion, reduces operating efficiency and leads to faster depreciation on skidders. Log butts should always be lifted above the ground during skidding. Steeper slopes should be logged by aerial or cable systems that cause much less physical environmental damage.
· Skid Trails: A carefully designed and supervised system of designated skid trails should always be used for log extraction. The following guidelines are recommended:
- Skid trail routes and density should be indicated in the harvesting plan and flag-marked within a forest. The aim is to extract logs causing the least possible damage to residual vegetation. Marking skid trail routes can assist the felling crew to align trees along skid trails. This practice reduces felling damage and extraction costs.- Skid trails should be as straight as possible to minimise soil and vegetation damage. Sharp comers should be avoided in order to protect trees and smaller plants growing nearby.
- Skid trail formation using a blade should be kept to a minimum. Manual cutting of skid trails is much to be preferred.
- Skidders should always remain on a skid trail. Rope should be manually pulled from a skidder to each log that is to be extracted to avoid the need for skidders to leave a skid trail. This practice minimises soil disturbance, soil compaction, and damage to residual trees, poles, saplings and seedlings. Skidder ropes should be at least 50 m long.
- Skid trails and skidders should not be allowed within streamside protection strips defined in a management plan or in national or local regulations. Skid trails and skidders should not cross gullies or streams unless it is absolutely unavoidable. If crossing a stream cannot be avoided, the crossing should be on solid rock or on an installed culvert.. Uphill Skidding: Uphill skidding is to be preferred to downhill skidding because it tends to cause less damage to soils and vegetation and also leads to more dispersed runoff of surface water. Logs being skidded uphill are more easily controlled, although uphill pulling does require more power and is more expensive. The choice of either uphill or downhill skidding in a harvesting plan needs to be evaluated and specified in a tactical harvesting plan in respect of the prevailing local forest conditions.
· Cable Extraction:
· Cable Log Extraction in Hill and Swamp Forests: Cable log extraction is only justified in sustainably managed tropical forests that are growing on long steep slopes or hilly terrain where log harvesting is technically and economically justified and watershed conservation is not impaired. It is also appropriate for log extraction in swamp forests. Cable extraction can be operated in conjunction with tractors for harvesting in previously logged forests where there is low and variable stocking. It does however have the advantage that it is less expensive than helicopter logging.· Skyline Cable System: Only the skyline cable log harvesting system should be permitted for selection harvesting in sustainably managed tropical forests because it is much less damaging to the forest structure than is the high-lead cable system. The high-lead system should not be allowed. A summary of aspects of skyline logging studies made in Malaysia are shown in Case Study 7.
· Log Extraction Using Draught Animals:
· Animal Skidding of Logs: Draught animals - specifically water buffaloes and elephants - are effective for extraction of small to medium sized logs on both flat and slightly hilly land. Animal skidding causes relatively low compaction and disturbance to soils and minimal damage to residual trees and smaller plants.· Planning:
- Extraction distances should be short, not more than 200 metres and preferably down slope.- Depending upon the type of animal being used, a maximum slope of 20 to 30 per cent for downhill skidding and 10 to 15 per cent for uphill skidding are suggested.
- Depending upon climatic conditions, terrain and log size, draught animals may not be able to work every day and may require relatively short days, no more than four hours. A reserve of animals (20 to 30 per cent) is desirable in order to maintain log production continuity.
· Ground Preparation: Skidding paths should be laid out and undergrowth vegetation cut to provide easy access for animals. Undergrowth should be manually cut close to the ground and thrown clear of the path. Stumps and old logs that could be an obstacle or a danger to animals should be cut low or removed. Stones should be rolled aside.
Case Study 7: Summary of Results of Skyline Logging Studies in Malaysia
|
A. Results of a Soil Disturbance Study After Harvesting with A Skyline Yarder | |
|
Soil Disturbance Class |
Area (%) |
|
No disturbance |
97.6 |
|
Litter layer disturbed |
1.1 |
|
Top layer exposed |
0.7 |
|
Subsoil exposed |
0.4 |
|
Subsoil heavily disturbed |
0.2 100% |
|
B. Skyline Yarding Costs for Three Operational Skyline Systems | |
|
System price (RM) |
544,000 |
806,000 |
628,000 |
|
Work days/year |
250 |
250 |
250 |
|
MOH/year |
900 |
850 |
900 |
|
Production/MOH (m3) |
8.0 |
8.0 |
7.6 |
|
Labour cost (RM/hr) |
9.6 |
11.4 |
11.4 |
|
Litre diesel/MOH |
5 |
10 |
5 |
|
Interest (12% per year) |
36.1 |
56.9 |
44.3 |
|
Insurance (1% of price) |
6.0 |
9.5 |
7.4 |
|
Repairs |
56.8 |
108.2 |
74.0 |
|
Fuel & Oil |
3.9 |
7.8 |
3.9 |
|
Labour cost |
128.0 |
187.0 |
176.0 |
|
Total Costs/MOH |
331.4 |
524.2 |
428.6 |
|
Total Costs/m3 |
41.4 |
65.5 |
56.4 |
Note: MOH == Machine Operating Hours
Source: The Malaysian-German Sustainable Forest Management Project
· Working Practices:
- Sledges and skidding pans can increase the productivity of animal skidding through reducing ground friction with logs and should be used if this is practicable.- Cutting should be coordinated with skidding, both operations proceeding together towards a log landing. This working practice enables animals to walk on clear skid paths, helps to avoid accidents and increases logging productivity.
- Animals must be well cared for, fed, watered and rested regularly.
- When a skidding operation has been completed, cross-drains should be cut across skidding paths to divert surface ground water into the adjacent forest thereby reducing soil erosion.
· Helicopter Extraction:
· Rationale: Helicopter log extraction is justified in sustainably managed tropical forests for four reasons:- where forests are growing on hilly land, close to stream buffer zones or on swampy land where the use of ground-based logging systems and roading could lead to unacceptable damage to soils, watercourses or to forest structure.
- where it leads to the most economic extraction of logs to landings, given the high production rate of aerial extraction, the high value of wood, the low roading density, construction and maintenance costs, the absence of skidding trails and minimal real costs for overcoming environmental damage caused by ground-based environmental damage caused by ground-based log
- where logs are inaccessible to ground-based extraction, such as across a gorge or above a long steep slope.
- where it is wished to limit entry of "slash and bum" farmers to a forest where the social pressure to use land for unsustainable agriculture is both a forest protection and management risk.
· Planning: Helicopter log extraction needs to be thoroughly planned and should involve teamwork by foresters, harvesting and helicopter management personnel. A harvesting plan should incorporate some flexibility to enable adjustments to be made in the event of rapidly changing working conditions. Planning should be carefully integrated with ground-based logging where there are economic, environmental or management benefits linking the use of both systems.
Case Study 8: Use of Elephants for Logging in Sri Lanka
|
The elephant has long been used in Sri Lanka for logging, before mechanised logging was introduced. As experience has accumulated, the elephant has come to be recognised as being very effective for logging, both in terms of cost and environmental sensitivity. It is in the context of environmental management of forests that the following advantages of using elephants have been identified: · Under forest conditions the elephant has the advantage of working in its natural environment and is familiar with the topography and trees. The elephant is an adaptable animal and this feature is an advantage when they are used for logging. · An elephant operates between a stump site and a landing using a track of about one metre in width, causing less loss and disturbance to forest than does a tractor. · The initial investment for a trained elephant in 1991 was between US$ 10,000 and U$ 15,000, compared with US$ 150,000 or more for a tractor. The average monthly running cost for an elephant is of the order of US$ 520, compared with US$ 795 for a skidder.. The foreign exchange requirement for buying and running an elephant is nothing but is considerable for buying a tractor, spares and fuel. · The use of elephants brings socio-economic benefits to rural communities through providing employment and food supplies for elephants. Elephants used for logging are slower and less efficient than machinery, resulting in lower productivity, but causing less damage to the forest ecosystem. |
Log Identification and Labelling
The following guidelines for log identification and labelling are suggested:
· The identity of trees that have been cruised and labelled for harvesting should be maintained through to log formation and delivery, at least to the landing.· Log loaders should ensure that cruising labels are firmly attached to the butt of the first log and that secondary labels are painted onto the large end of upper logs cut from the same tree. Skidder or tractor drivers should remove each cruising label that has been attached to the log butt by a cutter and carry these during log extraction to a landing. Each label should be handed to log scaling personnel on the landing. In the case of helicopter logging the identity of logs should be advised to log scaling personnel by the loader using two-way communication radio as each load is extracted to a landing.
Case Study 9: Experience of Helicopter Logging in Tropical Forests
|
In 1996 the ITTO featured an article in its newsletter, Tropical Forest Update, (Vol. 6, 3) on helicopter logging in tropical forests. This case study summarises the main technical and managerial advantages and disadvantages of helicopter logging over other systems: |
· Log labels, painted onto log ends, should be based upon the tree label. Cruising labels should be returned to a planning forester for use in a harvest assessment of the cutting area. The planning forester should match the duplicate tree labels collected by a cutter with those carried by the skidder or tractor driver as a part of the harvesting monitoring system.
Penalties for Forest Damage Caused During Log Extraction
Penalties should be imposed on extraction crews for careless working practices that lead to damage to residual trees during extraction, especially trees identified and labelled as future crop trees or reserved as seed trees, and also to natural regeneration. Each forestry agency should make penalty arrangements that are specific to the prevailing local situation. Frequent monitoring is needed to be able to detect extraction damage and to identify who caused it. Payment of a bonus should also be considered when good quality work has been completed.
The following practices should be applied in the design, construction and efficient operation of landings for log trimming, sorting and loading:
· Safety: The safety of all personnel is the foremost consideration in the conduct of landing operations and the safety and protection of all personnel and equipment working on a landing or nearby should be safeguarded. Effective training of logging crews is necessary to minimise accidents.· Location and Number of Landings: Where possible, landings should be located on slightly sloping ground. A gradient of about 2 per cent is often followed. Landings should be sited away from streams to minimise soil runoff. The number of landings should be kept to a minimum to reduce the loss of productive area and to minimise costs.
· Size of Landings: Landings should be as small as possible, bearing in mind the need for storage and sorting of logs, vehicle turning and loading.
- Where large logs are being handled and a knuckle-boom loader is being used for loading, landings can be as small as 20 m × 25 m (500 m2).- Helicopters and cable logging systems require larger landings. A typical landing area for these systems is of the order of 40 m × 30 m (1,200m2).
- Where landings are not needed, logs can be decked temporarily on roadsides and loaded onto trucks from there. This reduces the loss of forest, soil runoff and costs of landing operations. The use of knuckle boom loaders or self-loading trucks enables logs to be loaded directly from roads.
· Quality Log Handling: All logs should be delivered to a landing and transferred to the transport system without loss of log identity and without significant loss of volume or deterioration of quality.
· Site Protection from Spillage of Fuel and Lubricants: Care should be taken to prevent spillage of fuel and lubricants during refuelling and servicing of machinery. The refuelling area must be placed away from streams and earth ridges should be constructed to contain any spillage.
· Site Restoration: When landings are no longer needed they should be cleared of debris, including oil cans and machinery parts, compacted soil should be deep ripped and they should be planted using nursery-raised seedlings. Tree species selected should comprise those that are ecologically dominant in the locality and are expected to be commercially important as part of the next main crop.
All logs should be measured, or scaled, at landings in order that log volumes can be calculated. The measurement of log production in relation to a production target prescribed in a forest management plan is based upon consistently accurate log length and diameter measurements for deriving log volumes which is a critical indicator of sustainable management of a forest.
There are a variety of measurement methods used to estimate log volume. The choice should be made on the basis of value and log size, the scale of harvesting, the required accuracy, or as a negotiated part of a sale or management agreement. Whatever scaling system is used it must be fair to the buyer and to the seller of wood. The following practices and standards are suggested for scaling operations in tropical forests involving large logs:
· Responsibility: The forest owner as the seller of forest produce should be responsible for measuring log production. This approach is preferred to others because the owner is able to maintain firm control over the scaling procedure. In practice, the owner may not always have the personnel and supporting facilities to enable continuous scaling to be undertaken. Where this occurs, as it does on many large forest concessions, the responsibility for scaling should be delegated, as a condition of license or concession contract, to the concession holder, subject, however, to check-scaling by the forest owner.· Scaling Practices: The following guidelines can be adapted to prevailing local conditions for scaling of logs:
- Log identity should be painted onto both ends of every log and it should correspond with the cruising label tree number and the species code. Log identity, recorded as a code number, should be tallied against the tree number, taken from the cruising label. The species code should also be tallied.- Log length is assumed to be equal to the axis of the log and is measured using a logger's tape in metres and tenths of a metre along the surface. The tape must be kept parallel to the axis. The total log length should be measured and no allowance made for trim. Any trim taken off log ends should be paid for by the buyer, not the seller. This feature should be made clear in the sale and purchase agreement.
- Log diameter used for log volume derivation is mid-length diameter, measured over-bark, using a diameter tape or callipers at a point midway from the log ends. Any debris on the log, such as mud or loose bark, should be removed from the point of diameter measurement and the tape should be kept at right angles to the axis of the log. Log diameters from circumferences, measured using a tape, should be recorded in centimetres and tenths. A bark allowance, or twice the average bark thickness, should be subtracted. Bark allowances should be determined by separate studies for each species, or groups of species. The resulting under-bark diameter is usually rounded to the nearest even diameter class. Two examples are shown in Table 14.
Table 14: Application of a Bark Thickness Allowance
|
|
Example 1 |
Example 2 |
|
Species |
A |
B |
|
id-length diam. (over bark) |
93.6 cm |
81.8 cm |
|
educt bark allowance |
3.0 cm |
4.0 cm |
|
|
90.6 cm |
77.8 cm |
|
ally to nearest even cm |
90 cm |
78 cm |
- Log measurements should be tallied against the log number.- Log volumes should be calculated using a volume table based on cylinder volumes computed using Huber's Formula, defined as follows:
In practical terms the formula can be simplified by replacing p /40 with 0.0785398; Huber's formula then becomes:
V = d2 l 0.0785398
where:
V = log volume,
d = is the mid-length log diameter without bark,
l = log length
The log medium length cross-sectional diameter is also measured as the average of the small and large end diameters, under bark. This is the practice in parts of Africa.
Where exact log volumes are required, a log volume table based upon sectional measurement of logs can be used. It enables log volumes to be estimated from measurements of log length and the average diameter of the small end of logs. A volume table is calculated from a representative population of logs spanning the range log lengths and diameters of one species or of species groups that are being produced from a specific locality. Log volumes used to construct a volume table are calculated using Smalian's formula. It is applied to each section of log from under-bark measurements at the butt, 1.5 m, 3 m, 6 m, and so on from the butt until the small-end of the log is reached. Smalian's formula is defined as follows:
V= (d2+D2) ls 0.03927
where,
d2 = small end diameter (under bark)
D2 = large end diameter (under bark)
ls = log with length ls
p /80 = 0.03927
V = log volume
· Check Scaling: An essential feature of scaling practice is check scaling of the work of the scaling team. It should preferably be conducted by a two-person team led by a planning forester, or a qualified person who is directly supervised by a forester. Check scaling should be conducted regularly, but at randomly selected times. It should be a routine aspect of monitoring of log measurement practice.
Where a forest management unit is being managed by a concession holding company, or by an NGO on behalf of customary owners, the check scaling team should comprise company or NGO supervisory staff. Government forestry officials should conduct separate checks on scaling quality where the forest land is in State ownership. Check scaling should involve monitoring of the following three aspects of the scaling procedure:
- Log labelling and numbering practices, ensuring that log identity is clearly painted onto both ends of every log.- That log identity is tallied against the corresponding tree number, taken from the cruising label.
- Measurements of log length and diameter and allowances for rot.
The extent of check scaling will depend upon the confidence limits imposed by a forestry authority or set by the management of a concession company or cooperative. As a working guide there should not be more than a+/- 1% difference in calculated volumes between the scaling report and check scaling of the same batch of logs. Check scaling data should be processed in the same way as the main scaling data to ensure that valid comparisons can be made. The reasons for consistent differences between check scaling and scaling should be examined and discussed with the scaling team leader with a view to eliminating the differences.
Although log transport does not influence the management of tropical forests it can have an adverse impact on the forest environment and on the business operations of a company. It is for this reason that guidelines on log transport operations are provided. The aim should be to deliver logs safely to a point of destination without significant loss of volume and without adverse impacts on the forest environment. The following practices and standards should be applied in log transport operations in tropical forests:
· Safety: Good training of drivers in log loading, including "tie-ing down" of loads, daily care and maintenance of vehicles and careful driving is necessary to minimise accidents.
- Trucks should never be overloaded and the load must be evenly distributed.- Loads must be secured by binders that are of sufficient capacity to prevent logs from falling off the truck if a load should move during transport.
- Roads being used by logging trucks should be posted with warning signs, especially where trucks enter main roads.
· Road Maintenance:
- Roads being used for heavy log transport should be properly maintained in order to minimise erosion of the road surface and edges and for the safety of all road users. The need for adequate grovelling and grading should be planned and undertaken as a matter of practical road management where roads are being regularly used by logging trucks.- Roads should not be used, especially by loaded trucks, after heavy rain where there is a risk of serious road surface damage. Although local conditions can vary widely it is often advisable to allow a road surface to dry out for several hours before being used again for log transport. A waiting period to enable a road to dry will often reduce road damage markedly. Earth roads should not be used at all during periods of heavy rainfall.
· Refuelling: The same rules apply as for refuelling logging equipment.
A harvesting assessment is a systematic check made in the field during or following harvesting to determine the degree to which the operation is or has followed a harvesting plan and has complied with its objectives. It is an essential aspect of monitoring of the operational performance of a forest manager. A harvesting assessment provides information about the quality of operations, including the volumes cut and the condition of a forest following harvesting. It may be carried out while an operation is in progress (in-progress assessment), or after it is completed (post-harvest assessment). The following guidelines should be applied in forest harvesting assessments:
· Qualified Personnel: Assessments should be carried out by qualified planning and supervisory staff in the presence of operational personnel who are directly responsible for harvesting activities.
· Objectives: The extent to which operational performance has complied with the objectives of a tactical harvest plan should be assessed by examining key aspects of the plan.
· "In-progress" Assessment: An "In-progress Assessment" should monitor aspects of harvesting performance that need to be checked frequently. It should be a continuous or semi-continuous activity. Specific topics that should be checked are:
- That location and standards of roads, landings and skid trails compare with those specified in a tactical harvest plan. The use of GPS equipment can assist with checking road location.- That the harvest comprises only trees that have been cruised and labelled for cutting and that residual trees remain and are undamaged. Check that trees that were marked "not to be cut" but have not been felled, damaged or destroyed. If no, determine whether disciplinary action and imposition of penalties on those responsible is required. Check if trees that should have been cut have been left.
- That protected areas, such as streamside buffer strips and places of cultural importance, remain undisturbed.
- That directional felling, cross-cutting and log-making requirements are being complied with.
- That all logs have been extracted and transported from landings. Ensure that no logs have been left behind.
- That equipment and working practices conform with local safety requirements.
- That soil disturbance is being kept to a minimum.
- That fuel, oil and other possible contaminants are effectively contained and any spills have been properly disposed of.
- Whether roads have been closed, where specified.
- The effectiveness of directional felling for avoiding damage to residual trees.
Consideration should be given to applying penalties to harvesting crews where poor working practices are consistently observed.
· "Post-harvest" Assessment: A post-harvest assessment should monitor aspects of harvesting performance following an operation. It need not be carried out immediately but after sufficient time has passed for the environmental impacts caused by harvesting to become clear. This might be from six months to one year after harvesting has been completed. Specific topics to be checked are:
- The survival status of damaged trees, especially labelled "mother" trees.- A comparison of the location and standards of roads, landings and skid trails with specifications in the harvest plan.
- The extent and long-term effects of soil disturbance caused by log extraction, and determination of remedial action if any. What remedial action is required?
- Whether protected areas, such as streamside buffer strips, have remained undisturbed,
- Whether landings have been cleared of logging and mechanical debris and, where necessary, have been drained to prevent ponding of water. Check also whether landings need to be ripped for establishment of nursery raised tree seedlings.
- Assess whether oil and other contaminants have been properly disposed of and what remedial action is required.
· Reporting: The results of harvest assessments should be reported to the relevant authorities and to logging crews who carried out the work. Where it is appropriate a report should make recommendations for remedial action, for financial payments to personnel for work meeting specified performance criteria and penalties for poor performance. Questions of specific performance criteria, rewards and penalties should be determined by the management agency in relation to prevailing local conditions.
3.1 Forest protection
3.2 The participation of forest communities in forest protection
3.3 Post-harvest silviculture operations
Sustainable forest management can not be achieved in the absence of a firm commitment and action to effectively protect a forest management unit. Policies and legislation establishing a permanent forest estate, providing secure forest tenure, permanent definition and maintenance of forest boundaries, an operational capability to protect forests from fire and cooperation with forest communities, all contribute towards achieving effective forest protection. The following guidelines should be adapted to local forest conditions.
Forest Guards
Forest guards have an essential role for patrolling forest boundaries, roads and tracks and the interior of forest compartments to observe and monitor whether unauthorised operations may be taking place.
· Guards should work closely with harvesting, inventory and silviculture crews who also operate in a forest management unit.· Guards should be trained for their duties, including in public relations and in fire control. Where it is practicable, they should have earlier security experience. Distinctive uniforms are essential in order that guards are easily identified when patrolling in a forest.
Fire Prevention and Control
An effective capability should be organized and maintained in a condition of operational readiness in order that a rapid and effective response to forest fire emergencies can always be made.
· Fire Plan: When wildfire is perceived as a possible problem a fire plan for the prevention and control of fires should be prepared for a forest management unit, or specific parts of it, as a requirement of a forest management plan. Following approval, the fire suppression plan should be annexed to and form a part of the general management plan. Action to be taken by staff and workers if an accidental fire occurs should be clearly outlined in a fire plan, including the use of available equipment, the necessary manning strength in anticipation of a fire outbreak and the efficient clean-up and patrol of a fire area to prevent recurrence. Each fire plan should specify the following:
- The lines of command, control and communication amongst all personnel. A senior fire control officer (a fire boss), responsible to a chief forester for a forest management unit should be appointed. The fire boss could be a permanent officer having fire control responsibilities as a part of the job that also involves wood production.- Definition of the area to be protected on a topographical map at a 1:50,000 scale. Several copies of a fire control map should be available to operational staff to assist with communication. It should show:
* Road and track access routes for vehicles, and aircraft landing points.* Location of existing water points and proposals for construction of new water points.
- Vegetation fire hazard class map, identifying "levels of risk" for each broad vegetation zone.
- An equipment resources statement and specifications for procurement of new fire control equipment.
- A programme of public relations, education and advertising directed at strengthening public awareness of the need for protection of forests from wildfire.
· Communications: Radio and telephone arrangements should be provided to enable a fire control organisation to work efficiently to help prevent fire and to assist in suppressing fires quickly. Telephone and portable radio systems are also valuable for general communication for other forest management operations.
· Fire Danger Rating System: A fire danger rating system should be developed that is suited to the physical conditions of a province or to a forest management unit. Fire danger ratings show defined levels of fire danger, such as low, moderate or high, and are useful for explaining forest fire problems to local communities, to other sections of the general public and for putting forest staff on alert.. Records: A register and supporting maps should be established and maintained by a forest manager, recording the location, dates, reasons, areas and vegetation types lost or damaged by wildfires.
Where forest communities have a traditional dependence upon tropical forests which are being managed for wood production, their participation in the overall management process is important for achieving effective forest protection. Dialogue between representatives of local communities and forest managers is essential in reaching an understanding of the respective interests, and concerns, of each side and from which the foundations of forest protection can be developed. The following guidelines can be adapted to the prevailing local conditions for protection of a forest management unit:
· Sensitivity: Consultations with forest communities need to be positive, constructive and conducted with sensitivity and care using traditional as well as official discussion processes.· Informality: Consultations should be informal, conducted in the local languages, and be as easily understood as possible. It will be through informal and frequent discussion that the aspirations of local people may best be determined and understood thereby providing a firm basis for effective forest protection arrangements.
· Buffer Zones: Through community consultation, promote an understanding and acceptance of the use of buffer zones as a management and protection tool in localities where forest communities interact with wood production operations.
- Buffer zones should be developed within the context of specific forest management plans. The aim is to encourage investment in agriculture, agroforestry and other perennial crop systems and to discourage utilization of forests for which firm protection is needed.- The definition of buffer zones is a part of a wider strategy for classifying forest land where multiple use and protection of forests is contemplated. A medium to long term time horizon is necessary.
- Buffer zone development might be enhanced through the transfer of long-term land use and conditional management rights over buffer zones.
· Road Closure After Harvesting: Feeder roads that are not expected to be used again until the next harvest can be closed to prevent their use by local communities. Road closure practices can include ripping the surface and planting short rotation tree crops, shrubs or tall grass.
· Helicopter Logging: The reduced impacts on soils and forest vegetation that can be achieved through helicopter logging can have a protective effect on forests in relation to community relationships, as follows:
- Low road densities associated with helicopter log extraction reduces opportunities for squatters to encroach on forests and practise "slash and bum" agriculture,- Low impact harvesting causes little damage to medicinal, food and other plants that are of traditional value to forest communities.
General Guidelines
Silvicultural operations should be implemented in accordance with specific prescriptions set out in an approved management plan for a forest. The type and purpose of tending operations to be applied in each compartment, or sub-compartment, should be determined by diagnostic sampling. Tending decisions may also be based upon the conclusions of studies that have been made to gain a better understanding of forest ecology problems which are considered to be barriers to the effective practice of silviculture.
Responsibility for the implementation of silvicultural tending should be with the director of forest operations in the forestry agency, concession or a cooperative.
Operations being implemented should be part of a silvicultural system that has been designed to contribute towards the achievement of the management objectives of a forest. Silvicultural treatments should be applied within one or two years of harvesting, before regrowth makes movement difficult. Specific post-harvest silviculture operations can include:
· Enrichment planting using nursery-raised seedlings or forest transplants.· Release weeding, or forest cleaning, of undergrowth to reduce competition to existing seedlings, or to seedlings that might become established from seedfall.
· Liberation cutting of dense stands of trees and poles of commercial and non-commercial species.
Guidelines for Enrichment Planting and Release Weeding
The objective of enrichment planting and release weeding is to establish an acceptable stocking density of commercial tree species in a severely degraded and heavily logged forest.
* Planning
· General enrichment planting standards should be expressed in the forest management plan.· Specific proposals should be set out in the annual operational plan, based on diagnostic sampling. Compartments, timing of planting, and species to be planted should be specified.
* Species to be Planted
· Species should be selected from a list set out in the forest management plan. Importance should be placed on species comprising the forest type where enrichment is proposed and those having commercial potential for wood production.
* Forest Practices
· Planting lines or spots should follow contour.· Planting lines should be at least 1.5 m wide.
· Secondary vegetation larger than 6 cm diameter within a planting line or spot should be girdled. Vegetation outside the planting line or spot which will affect the planting site should be girdled.
· Generally, the best time for planting is near the beginning of the rainy season.
· The success of establishment should be evaluated in the forest regularly by field inspection of planted trees.
· Weeding should be carried out to keep transplanted trees free of competing plant growth. The need for weeding should be determined by field inspection.
Guidelines for Silvicultural Tending
The objective of silvicultural tending is to create or maintain favourable conditions for the growth of potential crop trees by removing competing vegetation. This is called liberation. A PCT is a species having wood of commercial value that is selected from the residual stand after logging and is tended to form the next crop of harvestable trees.
* Selection Criteria for a Potential Crop Tree
· A PCT should be a listed timber species for the locality, known to grow to loggable size (over 50 cm dbh). From an economical point of view, listed species should be defined by the forestry authority and should be shown in two lists, preferred species and acceptable species. Protected species should be listed separately and should include rare or endangered species and fruit trees.· It should be at least 5 cm dbh. A cluster of small trees may be equivalent to one PCT, providing the cluster has three or more individuals between 2 m in height and 5 cm dbh. There should be more than five individuals if less than 2 m in height.
· A PCT should have a vigorous, well-developed crown.
· It should have a straight, clear stem with no visible defects or injuries and should be a stable tree without a pronounced slant.
· A tree standing on the edge of a steep slope, a road cutting or within 20 m of a watercourse should not be selected.
· It should not be under the shade of another selected PCT.
* Selecting between Two Potential Crop Trees
· When a choice between two trees has to be made select the tallest tree having the larger diameter.· If both PCTs are of the same size select the preferred species over the acceptable species. If both are either preferred or acceptable species, select the tree having the longer bole. If both are equal in all respects, select the tree with the most uniform spacing.
· Select the PCT which is least likely to be damaged by the falling of a poison-girdled tree.
* Liberating a Potential Crop Tree
· Except for protected species, all trees competing directly with a selected PCT for overhead light should be removed. Trees whose crowns are well below those of a PCT need not be cut.· Individuals of preferred or acceptable species which are defective may be removed. Individuals of pioneer species may be removed if it is considered that they will compete with a PCT. Trees whose stem or branches may be or are rubbing a PCT should be removed.
It is not the purpose of these Guidelines to provide more specific guidance on the technical aspects of silviculture that can be applied in the management of tropical forests. Readers should consult relevant references on silviculture, included in the following section.
Brasnett, N. V. 1953. Planned Management of Forests. Alien & Unwin, London.
Davis, K. P. 1966. Forest Management. Second Edition. McGraw-Hill Inc., USA.
Dykstra, D. P. & Heinrich, R. 1996. FAO Model Code of Forest Harvesting Practice. Rome.
FAO. 1989. Management of Tropical Moist Forests in Africa. Forestry Paper No. 88, Rome.
FAO. 1989. Review of Forest Management Systems of Tropical Asia. Forestry Paper No. 89, Rome.
FAO. 1993. Management and Conservation of Closed Forests in Tropical America. Forestry Paper No. 101, Rome.
FAO. 1995. Elephants in Logging Operations in Sri Lanka. Forest Harvesting Case Study No. 5, Rome.
FAO. 1996. Addressing Natural Resource Conflicts Through Community Forestry. Community Forestry Unit, Forestry Dept, Rome.
Ford-Robertson, F. C. (Ed). 1971. Terminology of Forest Science, Technology Practice and Products: Multilingual Forestry Terminology Series No. 1. Soc. American Foresters, Washington, D.C.
Hutchinson, Ian D. 1991. Diagnostic Sampling to Orient Silviculture and Management in Natural Tropical Forest. Commonwealth Forestry Review, Vol. 70 (3), No. 223.
ITTO. 1996. Helicopter Logging Lifts off in Sarawak. Tropical Forest Update, Vol. 6, (3).
Johns, A. G. 1997. Timber Production and Biodiversity Conservation in Tropical Rain Forests, Cambridge University Press, Cambridge.
Johnston, D. R. Grayson, A.J. Bradley, R. T. 1965. Forest Planning. Faber & Faber, London.
GTZ-FD, Peninsula Malaysia. 1995. Development and Application of Operational Standards for Sustainable Forest Management in Peninsula Malaysia. Project Doc. No. 6, Kuala Lumpur.
