Scale and dynamics of a transforming forest landscape

Abstract

The widely used even-age management including small and uniformly sized regeneration areas together with the small-patterned private ownership are major features reshaping the Finnish forest structure. The object of the study was to examine the spatial and temporal dynamics of a real transforming forest landscape that consists of several privately owned management units. A forest area of ca. 9600 ha in the 1940s, 1960s and 1990s was used in the study. The effect of harvesting was examined by classifying the forest land into no-canopy and closed-canopy classes. No-canopy areas include both harvested and naturally open areas. Closed-canopy areas include development stages of young, middle-aged, mature and old forests. Different spatial scales were investigated by sampling the landscape with square windows. Largest patch index (LPI), mean patch size (MPS), area-weighted mean shape index (AWMSI) and edge density (ED) were calculated for the no-canopy class as an average of the sampled squares at the selected scales. Investigation of landscape metrics and their variability at several scales was more informative than averaging the entire landscape into a single index at a given scale. The study shows that forest management has clearly changed the structure of forest landscape in private forests during the time span under investigation. Presently, the changes caused by forestry take place at very fine scales, and therefore small sampling units are useful for the study of landscape structure.