Evaluating A Model To Predict Timber Harvesting In Austria : Integrated Tools for Natural Resources Inventories in the 21st Century

St. Paul

2000

S. 596-604

Bandaufführung

71851

Between 1981 and 1985, the Austrian National Forest Inventory (ANF) established a set of 5,500 clusters, each with four permanent plots, covering all Austrian forests. After the first remeasurement between 1986 and 1990, models were developed to predict tree growth, mortality, and the behaviour of forest owners in harvesting timber. A set of logistic equations describes the probability of a given stand exhibiting intermediate harvesting, single-tree selection, or final clearcutting. The independent variable were partly continuous and partly categorial, describing (1) regional units such as provinces, (2) types of ownership (groups of ownership sizes), (3) site factors (elevation and slope), and (4) stand characteristics (species mixture, density, mean diameter). The removal in the plots is given by five relative dbh classes. These removal percentage differ by elevation, harvesting categories, and tree species groups. A forecast of timber harvests in their spatial arrangement over Austria in the following four 5-year periods was made available to the public on a compact disk. In 1997, data from the second inventory remeasurements were available, and thus the forecasts for this period could be evaluated. Provided the units for which the forecasts were done are large enough, the results indicate that the deviations from the model are either small or can be explained by a then different timber market scenario and/or general socioeconomical scenario.