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18. The financial benefits of reduced impact logging: saving costs and the forest A case study from Labanan, East Kalimantan - Muhandis Natadiwirya* and Martti Matikainen**

* PT. INHUTANI 1, Manggala Wanabakti Block 7 Floor 12, Senayan, Jakarta 10270, INDONESIA, Tel: ++(62 21) 573 1765, Fax: ++(62 21) 573 4335, E-mail:

** Martti Matikainen, Forest Management Specialist, Berau Forest Management Project, Kompleks PT. Inhutani I Adm. Berau, Sei Bedungun, Tanjung Redeb, Kalimantan Timur 77134, Indonesia, Tel/Fax: ++(62 554) 2 1769


Conventional logging (CL) systems in tropical rain forests do not fulfil the objective of sustainable forest management. Under CL in Indonesia only a small percentage of the great variety and sizes of trees are harvested, but the damage to residual trees and the environment is disproportionate. This is recognized as wasteful and to improve overall performance the Indonesian government and industry are developing improved practices.

The Berau Forest Management Project (BFMP) is introducing a reduced impact logging (RIL) method in a forest concession owned and managed by P.T. Inhutani I. The project site is located in the Berau Regency in the province of East Kalimantan, Indonesia. The BFMP is a European Union co-funded project implementing a replicable model of sustainable forest management at an operational scale within the Labanan concession.

P.T. Inhutani I is an Indonesian state forest enterprise managing forest concessions located in several regencies in East Kalimantan and covering a total forest area of 1.1 million ha. Some 450 000 ha of these forests are located in the Berau Regency. Labanan, a concession of about 95 000 ha, is one of four management units in Berau, producing about 45 000 m3 of logs annually. The Indonesian selective cutting and planting system, called Tebang Pilih Tanam Indonesia (TPTI), includes a series of operations: forest gazetting, pre-harvest inventory, road construction, harvesting, post-harvest inventory, refining, liberation cutting, enrichment planting and thinning. Road alignment is done during the pre-harvest inventory. No work on skidding track alignment is done. As skidding is the major destructive operation during the harvest, it is important to correct this. Minimizing the length of skid trails reduces damage to the residual stand. This paper focuses on efforts to improve the accuracy of pre-harvest inventories and produce detailed tree-position and contour maps for efficient skid trail alignment. Particular emphasis is given to the financial results of a comparison of skidding under CL and RIL methods. The results of the full study, including a detailed comparison of physical inputs, outputs and performance, can be accessed through the BFMP web site (http:\\ or by reference to the P.T. Inhutani I or BFMP offices.


Logging treatments

Three logging methods were studied at an operational scale, covering 237 trips extracting 1 500 m3 of timber from three compartments (A, B and C). Compartment A was logged using a bulldozer and RIL techniques. Compartment B used RIL techniques and a combination of a bulldozer and a wheeled skidder. Compartment C was logged using conventional bulldozer techniques (Table 1). The bulldozer was a Komatsu D85ESS-2 (215 HP/1950 RPM, 20 950 kg operating weight), the wheeled skidder a was CAT 525 (175 HP/2200 RPM, 13 290 kg operating weight). The basic difference between the methods was in the planning of the operations. In the RIL plots, pre-harvest inventory and slope data were collected with a high degree of accuracy and used to produce high quality tree-position and contour maps with SIPTOP software developed by BFMP (See Figures 1a and 1b). A topographic map with a scale of 1: 2 000 was used to plan and monitor harvesting operations. Fellers and machine operators used a simpler topographic map (scale of 1: 4 000) to guide and record their work. The maps were used to locate crop trees and plan skid trails to minimize impact and maximize extraction; this resulted in skid trails usually located on crests to reduce cross-slope cuts and drainage problems, and extending as close as possible to the crop trees. Felling directions were defined by fellers to minimize turning when extracting logs. CL was done without proper planning. Fellers and bulldozer drivers located the crop trees without maps and cut skid trails according to the location of the felled trees.

Table 1. Summary of logging treatments




Maps used for skid trail alignment







Bulldozer, wheeled skidder






Data collection

During normal harvest operations, a team of enumerators recruited from Mulawarman University kept detailed records of 237 extraction events. For each trip, the following data were collected: time consumption by stopwatch; size of logs moved (length and diameter); time elapsed; terrain; slope; and distance. The data were used to calculate speeds and productivity by machine and terrain characteristics, and ultimately costs per cubic metre by using standard costs for machine use (capital and operating cost). The standard cost for bulldozer was computed at Rp 400 000 (US$ 60) per hour and for a wheeled skidder Rp 325 000 (US$ 50) per hour.


The results indicate that both log production costs and environmental damage are much lower under RIL than CL (Figure 2 and Table 2). The chief explanation is that bulldozer time used for skid trail construction under RIL is much lower than under CL. Bulldozer hours for skid trail construction were 2.8 times higher in a conventionally harvested compartment than in the compartment harvested under RIL. The skid trail area opened was 1.7 times that of skid trails in the RIL compartment. Cross-slope trails and cutting depths were also greater in the conventional plots, increasing soil disturbance and machine time. This is an important finding since bulldozer hours are the major cost element in the harvesting operation. It also highlights how careful planning can result in more efficient use of heavy machinery, lowering costs and reducing environmental damage.

Figure 1a. Mapping tree position and contours (produced by SIPTOP software)

Figure 1b. Planned skid trails

Figure 2. Skidding costs

Table 2. Skidding cost by bulldozer (Rp 1 000 per m3); calculated on the basis of physical machine hours

Work element

CL (C)


CL as % of RIL

Skid trail construction




Repair of skid trail




Travel empty




Winching and towing




Non-distance phases




Unavoidable time delays








The total cost of bulldozer skidding in a well-planned compartment applying RIL was only 67 percent of the cost of CL, mainly because of lower skid trail construction costs and avoidance of delays, both resulting from better planning. These savings were achieved during the initial adoption of RIL. By increasing the awareness and attitudes towards RIL, through training, incentives and other managerial improvements, the advantages of RIL could be further enhanced.

Comparing results for standardized compartments

The data were collected from actual operations. Obviously, compartments have different topographies, which might influence overall findings. To illustrate the savings, basic data were used to calculate the costs for a standard compartment using the three logging techniques. The standard compartment was 100 ha in area and 3 000 m3 of timber were extracted. The average skidding distance was 400 m. In the combined bulldozer-wheeled skidder operation, 30 percent of the timber was extracted by the wheeled skidder.

Under CL, the total costs were Rp154 million, and an estimated 48 days were required to log the compartment. A bulldozer using RIL techniques completed the same work in 32 days at a total cost of Rp 103 million. The combination of wheeled skidder and bulldozer completed the work in 30 days at a total of Rp 94 million.

The additional cost of improved planning required to execute RIL is estimated at Rp 4 million per 100 ha compartment. This is due mainly to improved data collection, which takes longer. Savings from more efficient pre-harvest inventory and reduced management time (32 days logging as opposed to 48 days) are not included in this comparison but would provide additional savings.


Planning - the basis for RIL

Successful implementation of RIL is based on improved planning of harvest operations. Reliable tree and topographic data for the compartments to be harvested are required. PT. Inhutani I has improved the accuracy of its pre-harvest inventory. The accuracy of identifying crop trees has improved from 30 percent to more than 90 percent on average. This makes for more realistic production targets, reduces the time wasted by fellers in identifying harvest trees, and avoids unnecessarily damaging skid trail openings. The inventory data are processed using the SIPTOP software developed by BFMP. This software produces inventory summaries, tree-position maps and topographic maps.

From planning to production

The cruisers and production supervisors plan the skid trail network, landings and areas that should not be logged (e.g. steep slopes) using the tree-position and contour maps. This exercise is based on both technical and environmental considerations. If necessary, the plan can be revised further, and corrected on the map, during the marking of trails and felling directions in the forest. After marking the skid trails, the production supervisor becomes responsible for the implementation of the harvest. In other words, the planning staff is responsible for producing accurate information; the production staff is responsible for performing low-impact and cost-effective harvesting.

Using maps in the skidding process

The fellers follow the marked skid trails and fell the trees in the directions that facilitate efficient skidding. They can mark the felled crop trees, as well as future crop trees on the map, and inform the supervisor and bulldozer operator of changes in order to avoid unnecessary openings.

Post-harvest assessment

After completing the harvest operation, the maps are used again to record damage. This post-harvest assessment could be done easily along all skid trails. The results can be used to modify the stand data from the pre-harvest inventory record, thereby eliminating the need to conduct a complete post-harvest stand inventory, as would be required under the conventional TPTI logging system.

Indicators of environmental impact

Bulldozers are very powerful and can damage the environment substantially. The results of this study suggest that the more hours bulldozers are active in a compartment the more damage they inflict. Consequently “machine hours per hectare” or “machine hours per cubic metre extracted” could provide an excellent operational level indicator of environmental impact. These indicators have the added advantage of being related directly to operational costs. Thus, managers, accountants and environmentalists will all find this indicator relevant.


Awareness of the running costs of skidders is important for optimizing their use. The cost of a bulldozer travelling without a load is more than Rp 100 000/km. Skid trail construction in CL took 2.8 times as long as in RIL, resulting in costs of Rp 3.9 million/km for CL compared to Rp 1.5 million/km for RIL. Log size is the most significant factor in the speed and productivity of skidding. Productivity (m3/hour) improves as log size increases. Skidding with a bulldozer in CL costs 50 percent more than bulldozer skidding under RIL. Under RIL, extraction from one compartment can be accomplished in 30 skidder days instead of 48 days under the current system. Good planning, based on an accurate pre-harvest inventory, used as a tool for supervision and implemented under RIL, can save as much as Rp 60 million (US$ 600) in skidding costs in one compartment alone. Machine hours per hectare or per cubic metre extracted could be an excellent indicator of environmental impact and has the added advantage of being related directly to operational costs.

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