Minimum area of forests left to spontaneous development in protected areas

摘要

Search for ecological criteria for decisions on forests to be left to spontaneous development in specially protected areas is based on the knowledge of regularities of autochthonous or natural forests. They are mainly relative constancy of the species composition of communities, relative all-agedness, relative equability of growing stock and relatively small areas of the particular developmental phases and stages. They will lead to the maintenance of ecological autonomy and equability of natural forest; their basic condition is to determine a minimum range (area) of forest stand when the populations are still maintained by autoregulation. The output of this study is applicable methodology and tests of its applicability in 36 localities in spruce woods, beech woods, mixed stands, scree forests, oak woods, floodplain forests and pine woods [in Sumava National Park (SNP), Krkonose National Park (KNP), Protected Landscape Area (PLA) Broumovsko, PLA Cesky kras, PLA Jizerske hory Mts., in nature reserves at the foothills of the Orlicke hory Mts. and in Polabi Lowland]. The objective was to define minimum ranges for natural environmental conditions and for two situations under the existing air pollution environmental conditions.