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2. Study setting

2.1 Site description

The FOMISS-Samling Pilot Area (FSPA) is located in the Upper Baram region of Northeast Sarawak. The FSPA consists of two timber licences (T/0411 & T/0412) covering a total area of 169,000 ha. The mean annual rainfall amounts to 4,600 mm in the entire FSPA and to 5,000 mm for the RIL blocks respectively. The area is built almost entirely of sedimentary rocks and is characterised by moderately sloping to steep mountainous topography. Approximately 56% of the area has gradients exceeding 25.

Table 2 compares the slope distribution of the RIL blocks with the average conditions in the FSPA. The major soil groups in accordance with the FAO classification (Spaargaren, 1994) in the entire FSPA as well as in the RIL trial blocks are Regosols / Acrisols.


Table 2. Distribution of slope classes for the FOMISS-Samling Pilot Area (FSPA) and the RIL trial blocks.

Slope class


Percentage of area in slope class




Entire FSPA [%]

RIL Blocks [%]


Class 1

0 5




Class 2

5 15




Class 3

15 25




Class 4

25 35




Class 5

> 35




Source: FDS (2000) & GIS data base


The FSPA is covered by four forest types (Table 3). The Mixed Hill Dipterocarp Forest (MHDF) forms the dominant forest type, covering about 80% of the area. The other forest types are Kerangas, Mountain, and Limestone forests. Approximately 50% of the area is primary forest with an average commercial volume of 303 m/ha. The average stocking of logged-over forests amounts to 170 m/ha.

To summarise, it can be stated that the ecological environment of the selected RIL trial blocks is comparable with the average conditions within the FSPA.


Table 3. Forest types in the FOMISS-Samling Pilot Area (FSPA) and the RIL trial blocks.

Forest type

Area covered by forest type


Entire FSPA [%]

RIL Blocks [%]

Mixed Hill Dipterocarp Forest

Low densitya



Medium density



High density






Kerangas Forest



Limestone Forest



Mountain Forest



Source: FDS (2000) & GIS data base

a Density classes refer to crown closure

2.2 Timber harvesting systems

2.2.1 Reduced-Impact Logging

The step-wise procedure of the RIL system tested in the FSPA is summarised as follows (for details refer to Jonathan et al., 1999):

      1. The first step involves the alignment of skidtrails. Skidtrail gradient is limited to 27% (15°), except for short distances of up to 20 m.

      2. The skidtrail alignment is mapped and the harvestable trees are marked (including the planned felling direction) and climber cutting is carried out.

      3. Data are entered into a database and analysed. A Final Harvesting Map (FHM) is produced that shows skidtrails as well as areas to be excluded from timber harvesting.

      4. The FHM is reviewed by verification and crosschecks.

      5. Contractors, FOMISS & Samling RIL field supervisors, and field staff are informed about the harvesting plan.

      6. The harvesting operation is carried out in accordance with RIL guidelines. A Caterpillar D6 DLS crawler tractor with winch is used for skidtrail and log landing preparation as well as for log extraction. The tree fellers use Stihl 07 chainsaws and are trained in directional felling. Trees are winched from the stump to the skidtrail and tractors are not permitted to leave the skidtrail. All trees felled and extracted are recorded. FOMISS/Samling field supervisors monitor the complete harvesting operation.

      7. Post-harvesting, a damage assessment is carried out (only for the trial phase).

      8. The RIL trial is analysed, including a RIL compliance assessment.

2.2.2 Conventional Logging

The Conventional Logging is also carried out with a Caterpillar D6 DLS crawler tractor. In contrast to the RIL system the winch is only used for short-distance log extraction and breakouts from the skidtrail are common. Log skidding occurs immediately after tree felling. The tree fellers make tree-felling decisions. Stihl 07 chainsaws are the standard equipment. Trees are usually felled in the direction of their natural lean. CL and RIL still use the same payment system: machine operators, hookmen, and sawyers are paid per hoppus ton (1.8 m). Under the CL system no pre- or post-harvesting operations are conducted.

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