SUMMARY

The study was carried out in the tropical natural forest, concession area of PT. Sumalindo Lestari Jaya IV in Berau Regency, East Kalimantan, Indonesia. This study analyses productivity, costs and environmental impacts of conventional and reduced impact timber harvesting of the Indonesian Selective Cutting and Planting (Tebang Pilih Tanam Indonesia/TPTI) system.

The conventional and reduced impact timber harvesting operations were observed; both methods used the same equipment and operators and were conducted in almost the same area. Felling was done with heavy chainsaw and skidding with crawler tractor (bulldozer).

Time studies were elaborated for felling, skidding, bucking, loading, hauling and unloading activities to assess timber harvesting performances, productivity and costs under comparable conditions of conventional and reduced impact timber harvesting. Environmental impacts assessments were carried out only for the felling and skidding operations.

The result of the time study for felling shows that the average time needed for felling in conventional timber harvesting for trees with buttresses is 24.24 minutes per tree and for trees without buttresses the average needed is 14.17 minutes per tree. In reduced impact timber harvesting, the average time for felling trees with buttresses is 21.88 minutes per tree and for trees without buttresses the average needed is 15.82 minutes per tree.

The productivity of felling in conventional timber harvesting for trees without buttresses is 11.88 m³/hour; for trees with buttresses is 17.63 m³/hour. In reduced impact timber harvesting, the productivity of felling trees with buttresses is 18.34 m³/hour and for trees without buttresses it is 10.15 m³/hour.

The cost of the felling operation in conventional timber harvesting was Rp 1 141.10/m³ and in reduced impact timber harvesting the cost was Rp 1 080.78/m³. This means that the felling cost decreased to Rp 60.32/m³ (5.29%) for reduced impact timber harvesting compared with the felling cost of conventional timber harvesting.

The average skidding distance in conventional timber harvesting operations was 350.6 m, and caused an opened area of 872.53 m²/ha or 8.73%; in reduced impact timber harvesting operations, the average skidding distance was 335.2 m, and caused an opened area of 520.81 m²/ha or 5.21%.

Time required and productivity of skidding in conventional timber harvesting was 38.14 minutes per round trip with a productivity of 6.47 m³/h; in reduced impact timber harvesting it was 33.01 minutes per round trip with a productivity of 7.31 m³/h. The time involved for construction of skidtrails in reduced impact timber harvesting was 3.61 minutes/m³ of harvested log. Therefore the skidding cost was Rp 10 971.77/m³ in reduced impact timber harvesting or 2.22% higher than skidding costs in conventional timber harvesting (Rp 10 728.12/m³).

The comparison between environmental impact caused by conventional and reduced impact timber harvesting operations is as follows:

This comparison shows that reduced impact timber harvesting can reduce damage up to 50% when compared with conventional timber harvesting.

Comparison of production costs of felling, skidding, bucking, loading and unloading of conventional and reduced impact timber harvesting shows that the total cost of timber harvesting in conventional timber harvesting is Rp 28 081.29/m³, while in reduced impact timber harvesting it is Rp 28 264.62/m³. The cost here does not include topographic maps and timber harvesting planning costs.

Assuming that the profit ratio is 30%, the loss of value is twice as great in conventional timber harvesting as in reduced impact timber harvesting (Rp 28 24l.68/ha and Rp 12 433.42/ha).

These research results indicate that conventional timber harvesting with the TPTI System in the tropical natural forest in Indonesia caused heavier damage on soil and residual stands when compared with a reduced impact timber harvesting system.

The application costs of reduced impact timber harvesting are not greater than conventional timber harvesting in either short or long periods because the wood damages value caused by conventional timber harvesting is twice as great as that caused by reduced impact timber harvesting; also, reduced timber harvesting will enhance future forest productivity and reduce the costs associated with potentially adverse side-effects of timber harvesting.

This case study is in response to the FAO model code of forest harvesting practice (D. P. Dykstra and R. Heinrich, 1996) to promote forest harvesting practices that improve standards of utilisation and reduce environmental impacts, thereby contributing to the conservation of forests through their wise use.

Further actions are recommended in order to:

· promote the implementation of the reduced impact wood harvesting in the tropical natural forest;

· develop the local codes of practice of reduced impact timber harvesting operations;

· conduct regular training for chainsaw operators, tractor operators, felling and skidding foremen and timber harvesting supervisors and planners;

· improve payment/salary systems, e.g. tariff systems based on work quality, quantity and working place conditions; and

· promote studies that reduce environmental impact in tropical natural forests, e.g. by providing alternatives to crawler tractor timber harvesting methods on steep slope, namely skyline and helicopter timber harvesting.