Optimal planning of timber extraction methods using analytic hierarchy process

Timber extraction is one of the most difficult work stages of forest operations in Turkey. Inappropriately, planned timber extraction operations can be very time-consuming activities and may also cause serious damage to residual trees, saplings, and forest soil. Thus, an optimal timber extraction method should be determined considering both economic and ecological constraints. In this study, commonly implemented timber extraction methods including chute system, portable winch, and farm tractor were evaluated with respect to their productivity and potential damages on residual trees. In the solution process, one of the well-known multi-criteria decision analysis (MCDA) techniques, the analytic hierarchy process (AHP), was used to determine optimal timber extraction planning of priority scenarios. Specific timber extraction methods were identified and evaluated based on slope, volume, and distance criteria. A total of five priority scenarios were examined: (1) optimal extraction with the highest productivity, (2) optimal extraction with the lowest stand damage, (3) productivity and stand damage receive equal importance, (4) productivity is more important than stand damage, and (5) stand damage is more important than productivity. The AHP results indicated that the optimal timber extraction method was the farm tractor winching with 30 m skidding distance in Scenario I. On the other hand, the portable winch with 20 m skidding distance was found to be the optimal method with the least stand damage. In Scenario III, the portable winch, with an average skidding distance of 40 m, was found to be the most suitable extraction method. The overall results indicated that implementing MCDA techniques for optimal planning of timber extraction will help provide important contributions to conduct economic, environmental, and site-specific operations during logging stages.