Spatial Analysis of a mixed Beech, Spruce and Fir stand in the Eastern Alps

In a forest reserve, located in the Eastern Italian Alps, a 4 ha permanent plot has been set up in a beech-spruce-fir multilayered forest, left to natural evolution for more than 30 years, in order to detect stand structure and spatial patterns. Additionally, within the 4 ha, we selected 1 ha where data related to age were collected (coring all the individuals above 6 cm in diameter) and to test the efficiency of the statistics at 2 different spatial scales. The methods employed were the univariate and bivariate O-ring statistic together with autocorrelation indexes such as Global Moran’s I and local Gi*. Thus, it has been possible to perform both the point pattern and the spatial structure analyses. Diameters’ distribution highlights a slightly multilayered structure for groups whose tend to be even-aged and monospecific. O-ring statistics have highlighted a general aggregation pattern up to the oldest stages while the spatial structure analyses have highlighted a macroscopic trend which divide the stand in two distinct and homogeneous big groups of individuals. Secondly, a different behavior is detected among the species, i.e. the beech is likely to prefere to regenerate under the old spruce and the two conifers prefer to grow in very localized conditions. A huge lack of young individuals has been detected due to deers’ browsing. Lastly, the age has proved to be a fundamental parameter to fully describe, together with the most common species, diameter and height, the structure of forest stands. The comparison between the 1- and the 4-ha analyses has confirmed the key role of the dimension of the larger permanent plot in detecting the whole range of spatial features within a stand. The results obtained from this work provide an important support for the analyses of similar stands in terms of evolution and natural dynamics occurring after the human pressure decreasing.