Further development of GIS-compatible estimation-models for forest energy wood based on forest inventory- and planning-data.

摘要

Facing an increasing interest in forest timber as a regenerative energy source, this paper aims to derive a practical and plausible method to determine the potential of wood as energy source. The predictions should be repeatable, up-to-date, regionalized and should show a sufficient spatial resolution. This study was integrated into a geographic information system to derive the spatial distribution of wood as energy source in the study area [Germany]. The applicability of 'Freiburg method' was examined. The database required for this study were the inventory data of the forest enterprises and the harvested volume and the planned harvesting adopted from the inventory-based forest planning data. The potential volume of forest energy wood for different management operations (tending of young stand, thinning, target diameter felling, final felling, continuous cover forestry, etc.) of the respective potential ecological forest type (superordinated stratum) in each forest enterprise, regarding the forest planning data and a general deduction due to technical restrictions, were derived. This analysis was based on two bucking alternatives, the 'traditional' and the so-called 'log-PLUS' type. The conventional type representing the conventional way of bucking, aims to optimize bucking regarding the options in the non-energy use of wood, whereas the purpose of the 'log-PLUS' bucking alternative is to optimize the allocation of material to non-energy and energy-use. This 'Freiburg method' was used in a test run, considering the state forests in the Hochschwarzwald/Breisgauer Bucht region with a total area of 6641 hectares. Assuming a potential felling volume of 11 cubic metres (over bark) per year per hectare, a mean theoretic-technical potential of 1, 5 m3 ob year-1 ha-1 (or ~10 000 m3 ob year-1 in the total area) was calculated based on the 'traditional' variant. In contrast to this, the 'log-PLUS' variant accounted for an average theoretic-technical potential of 3.9 m3 ob year-1 ha-1 (or ~26 000 m3 ob year-1 in the total area)..