HARVEST LAYOUT PLANNING FOR HIGH-ALTITUDE PROTECTION FORESTS

An increasing share in the forest area of the European Alps has to provide protection services to prevent natural hazards, such as avalanches, rock falls, erosion, and floods. Protection forests require special treatment to maximize sustained mechanical stability. Although there is a significant knowledge of growth characteristics and silvicultural regimes for high-altitude protection forests, there is a lack of knowledge of how to suit harvest layout to silvicultural layout. The paper aims to (1) outline the growth and management characteristics of high-altitude protection forests, (2) to provide an approach for harvest layout planning for cable-based systems under those conditions, (3) to discuss some typical harvest swaths geometry patterns for protection forest tending. Silvicultural interventions mainly consist of laying out about two regeneration slits per hectare, which have a size of about 0.05 hectares. The harvest engineer aims to concurrently suit the regeneration slit layout to the cable corridor layout for a whole area. This task is very demanding, and has still to be done manually. Defining harvests swaths geometry is the next step in layout planning. It has to define the spatial order of tree felling relating to cable road directions and to harvest system layout. Layout planning is the crucial step to minimize damages to residual trees, and to maximize economic efficiency of operations.