INFLUENCE OF EXISTING SECONDARY FOREST ROAD NETWORK ON THE SELECTION OF TIMBER EXTRACTION TECHNOLOGIES AT THE TACTICAL LEVEL OF PLANNING

Abstract

Planning is an intellectually demanding process that requires a conscious determination of actions and decisions based on related purpose, knowledge and right decisions. During planning timber harvesting it is very important to choose the best possible technology for timber extraction. The use of multi-criteria-decision-making models is a very good way of dealing with various forestry issues especially in terms of choosing the best applicable technology for timber extraction. Modern forest management in the Republic of Croatia in terms of timber harvesting mostly relies on ground based wheeled systems. The goal of this research is to show how the current way of planning timber harvesting (timber extraction) and accordingly the construction of secondary forest road network affects future planning and introduction of »new« technologies for timber extraction i.e. forest cableway. Analysis of suitable forest stands for different timber extraction technologies s was carried out in the management unit Garjevica-Cazma with an area of 4380.20 ha. The paper presents multi-criteria-decision-making model for defining terrain suitable for ground based wheeled systems (skidder with a winch and forwarder) and forest cableway on the base of raster maps (grid of 20×20 m i.e. 0.04 ha). The criteria used to select different technologies for timber extraction were: terrain slope, distance from the forest road, distance from the skid road and harvesting density. Analysis using GIS tools in ArcGIS and Idrisi applications goes in two directions, first the analysis of suitability of using selected technologies for timber extraction using four criteria, and comparison with results of the analysis where the criterion »distance from the skid road« has been excluded.