Timber production possibilities of the Norwegian forest area and measures for a sustainable forestry

This paper presents long-range forest management analyses with the objective of mapping consequences for the timber production potential when forest management treatments are changed in an environmentally oriented direction. Sample plots from the National Forest Inventory, covering the entire productive forest area in Norway, were aggregated into 10000 treatment units. Management strategies maximising the net present value of the forest-land, with certain environmentally oriented constraints, were analysed. The following environmentally oriented constraints were considered: (i) areas of current old forest set aside, either proportionally or cost-efficiently, for permanent preservation, (ii) minimum target levels for area covered by old forest through time, (iii) retention of trees at final felling, and (iv) restricted management for border zone areas. With a real rate of discount of 2.5%, and all the constraints imposed simultaneously, the annual harvest potential was reduced by 30% for the first 10-year period, while the net present value was reduced by 21.5%. The results further demonstrated significant efficiency gains of letting the preservation of old forest be allocated cost-efficiently, compared with a strategy of setting aside an equal portion on all eligible areas.