The larch wood pasture: structure and dynamics of a cultural landscape

As a consequence of land abandonment and marginalization, open areas and traditionally managed wood pastures are disappearing from many alpine valleys. Landscape and stand scale dynamics were analyzed in two neighboring inner valleys of central Italian Alps (Valmalenco, SO) dominated by larch (Larix decidua Mill.) forests and experiencing different historical land use intensities. Land cover mapping obtained from object-oriented analysis of aerial photographs was used to quantify land cover changes between 1961 and 2003. Spatial statistics were used to quantify landscape patterns, and intensive sampling in permanent plots was employed to perform point pattern analysis at the stand scale. Expansion of forested area at the expense of wood pastures was the main land cover transition observed. Differences in land use intensities were responsible for different patterns at the landscape scale: (1) heavier grazing and human pressure created a more diverse and fragmented mosaic of meadows, open woodlands, forests and wood pastures, (2) lower human impact favored a more homogeneous and stable system. A decline in grazing pressure in the late 1970s favored the establishment of larch and spruce in a clustered pattern, typical of the subalpine belt. Subalpine wood pastures, likewise many other semi-natural environments, are in danger of disappearing and lose their productive and cultural characteristics, because they are developing into more closed and dense stands.