2. TYPICAL CONVENTIONAL TIMBER HARVESTING OPERATIONS IN INDONESIA

According to J. Hendrison (1990), conventional timber harvesting is unplanned, haphazard harvesting. In this case, timber harvesting operations are not based on a forest inventory and the harvesting area is not laid out before felling. In addition, harvesting operations are not planned or organized and are very often performed by unskilled crews. As a result there is large wastage of harvested timber and considerable harvesting damage. No attention is given to the remaining forest stand and harvesting costs are high.

The typical conventional timber harvesting in the tropical natural forests in Indonesia is conducive to insufficiently planned and improper technique application and lack of control, e.g. the skidtrail network and directional felling are not planned and laid out before felling operations; felling technique is still inefficient (notch and back cut is still too high); the chainsaw operator and the tractor operator work independently and do not use tree location maps to aid their activities; the tractor operator searches for logs by using his helper to look for logs on the ground.

2.1 Forest inventory

Before timber harvesting takes place, a stock survey is carried out which provides information for the calculation of the yield, and for the identification of the harvestable trees. The forest inventory and yield calculation may take up to one year, therefore it is conducted two years prior to harvesting. The forest inventory is a 100 % survey of trees with a diameter 20 cm and upward.

The forest inventory is conducted by a team of timber cruisers. They consist of 6-10 persons, including at least one tree evaluator, one recorder, one compassman and the others are helpers. The team's task is to carry out a forest inventory. The data collected consists of tree species, tree diameter, tree height, tree distribution/location and tree marking for harvestable trees, protected trees and nucleus trees. The survey method uses the systematic strip line with random start. On the average, daily accomplishment is 2-4 km or 4-8 ha per team.

The collected information is then tabulated and used both for an estimation of the stock wood volume of harvestable trees and to produce a tree location map with a scale of 1:1,000 (see Figure 1). This information, together with other required data, has to be formulated as part of a "Yearly Operational Plan" (Rencana Karya Tahunan/RKT).

Figure 1. An example of a tree location map (scale l : l,000)

2.2 Road planning and construction

2.2.1 Road standard and road density

Generally, the method of designating road standards in the tropical natural forest in Indonesia is by a service standard. The Opening Up Forest Guidelines of TPTI recognizes four standards of hauling roads in forest concession areas, namely:

· main roads with surfacing

· main roads without surfacing

· branch roads with surfacing

· branch roads without surfacing

The typical road standard used in forest concession areas in the tropical natural forest in Indonesia is shown in Table 1.

Table l. Typical forest road standards in forest concession areas in the tropical natural forest

in Indonesia

The road density in the tropical natural forest in Indonesia ranges between 10-25 m/ha, with an average of 17 m/ha.

2.2.2 Road planning and road construction

Road planning in the tropical natural forest in Indonesia has been conducted until now in a very simple way, which is also insufficient and inefficient. Generally the road surveyor inspects the ground with a compass to locate the road trace route by orientation of the topography. After ground orientation the road surveyor draws a road trace route by stacking the central line of the road trace and marking it with red paint, usually on the trees.

The final road location/layout is decided by the road surveyor team after detailed field observation is completed. The team finalises road location by considering required road grades and physical obstacles on/in the ground. The team of 4-6 workers can accomplish around 1 to 3 km/day.

At this point the road construction can be started. Generally the steps are as follows (see Photo 1):

· Piloting
Piloting is the first operation in road construction necessary to make a strip (line) with a dozerblade on the centreline. Bulldozers are the basic equipment used to open the strip. The width of strip-piloting is about 5 m.

· Opening
Opening consists of activities needed to open the strip and may be defined as the removal of trees, stumps, roots and other objectionable matter from the road construction areas. Bulldozers are the basic equipment used to clear and grub. Opening is done to provide access for timber salvage on the right-of-way and is followed by the dozing of stumps and trees on the right-of-way area.

· Grading
Grading includes those activities necessary to construct the road after the construction area has been opened. Earthmoving is usually done by bulldozers over short distances while dump trucks and loaders are used for longer distances. Bulldozers and motor graders are the basic equipment used in grading.

· Shadow felling

To dry out the road, it is common to "daylight" the road by "shadow felling". Shadow felling is generally conducted during the grading phase. Chainsaw is the basic equipment used to fell trees. The width of shadow felling along the left and right side of the road is 20-25 m.

· Compacting
Compacting includes those activities used to compact the road construction. The vibration roller is the basic equipment needed to compact the soil.

· Surfacing
All-weather forest roads require a surface application of rock, gravel or acceptable surface material. This material is usually brought into the road from local quarries. The material is hauled by dump truck and spread with motor graders. Compacting is done with a vibration roller.

· Finishing

The final steps in road construction is the crowning, sloping of shoulders and slopes and ditching. This is usually accomplished with a motor grader. Table 2 shows the steps necessary for road construction.

Table 2. Productivity of road construction in the tropical natural forest in Indonesia

2.3 Felling

Felling in the tropical natural forest in Indonesia is done with a chainsaw equipped with a 60-70 cm guide bar. Equipment to facilitate felling with a wedge is not commonly used. The minimum diameter of tree to be cut is 50 cm. Usually each chainsaw has one operator and one helper, who work for 6-7 hours per day with an average production of 12-18 m³/h. The productivity in felling is shown in Table 3.

Table 3. Felling productivity in the tropical natural forest in Indonesia

Generally, the forest concession owners use the contract system in which felling crews own the chainsaw and the company pays the crews by the piece-rate system. Photos 2 and 3 show the equipment and felling technique and the steps for felling in the forest concession areas in Indonesia.

2.4 Extraction

Most of the forest concessions now are operating in the hilly/steep terrain areas. For the extraction of logs from the forest stand to the landing, the equipment commonly used in the tropical natural forest in Indonesia are crawler tractors, such as the Cat D7 and Komatsu D 85E-SS. These crawler tractors can work on steep slopes; they are equipped with a robust dozerblade and a powerful winch.

The skidding team consists of one tractor operator and one helper, operating for 6-7 hours/day. Each team can produce around 17 to 29 m³ logs per hour for an average skidding distance of 300-400 m. The skidding productivity is shown in Table 4.

Table 4. Skidding productivity in the tropical natural forest in Indonesia

Photo 4 shows skidding operations in the tropical natural forest in Indonesia. Generally the tractor operator searches for logs by using a helper, who looks for logs on the ground. Then the tractor operator opens the skidtrail to the logs and moves towards the logs until the helper can easily hook the log with the winch cable. Winching the logs are generally only for a very short distance (about 1-5 m). Logs are then skidded to the landing.

2.5 Landing

The main activities at a landing are bucking of logs, debarking, scaling and loading logs to the logging truck. At the landing the logs are bucked into more manageable lengths by a chainsaw operator and then debarked with a crowbar by a team of four persons. The logs are then loaded onto a logging truck. The commonly-used equipment for loading are a wheeled loader Komatsu WA500. Performance is about 100 m³/h for bucking, 15 m³/h for debarking and 72-76 m³/h for loading. Photos 5 and 6 show the main activities at a landing.

2.6 Wood transport

The procedure following landing operations is the transport of logs from landing to mill or market. It is mainly carried out by truck hauling and raft towing. Truck trailers are most commonly used in hauling operations in the dryland tropical natural forest in Indonesia. The process of timber transport by truck trailer in a dryland tropical natural forest is shown in Photo 6 and by water transport in Photo 7.

The types of truck trailers commonly used are the Nissan TZ 52, Kenworth C 500, Nissan TZA 52 ZHN and Nissan TZA 52 PPN. The timber transport productivity according to the type of truck trailer is shows in Table 5.

Table 5. Timber transport productivity by truck trailer

Generally, forest concessions need to raft their logs to mill sites. The logs are delivered to a dumping place in the water (log pond) and rafts are built. Finally, the rafts are towed to the mill sites by two tugboats of 110-120 HP, which can tow 400-600 m³ of logs. The towing distance is around 100-800 km.