Jämförelse av URM, URM med areatillägg och ARM för att begränsa sammanhängande hyggesstorlek

Sammanfattning

In this study, various models for limiting the size of clear-cut areas have been examined and compared using the decision support system Heureka Planwise. The models utilized in the comparison include the Unit Restriction Model (URM), URM-A, which is the URM with an additional area restriction limiting the combined area of two adjacent clear-cuts, and Heureka's built-in module, the Area Restriction Model (ARM). The study was conducted to investigate the challenges and opportunities of these different models in relation to the Swedish Forestry Agency's definition of close-to-nature forestry released in 2023. In this definition, the Swedish Forestry Agency defines close-to-nature forestry, among other criteria, by the key measure Ensuring gentle harvesting. This means that the maximum clear-cut size is 2 hectares in Götaland and 4 hectares elsewhere in Sweden. The results of the work showed that ARM managed to create a better distribution of final harvestable units over the planning horizon than the other models. A higher NPV was generated while the restrictions were adhered to. The disadvantage of ARM was the solution time, which was almost 3 times longer than in the other models.