Grundzüge der Vegetationsgliederung Niederösterreichs
[Geomorphology of Lower Austria]
Hübl, Erich; Holzner, Wolfgang
Lower Austria is the geomorphologically most diversified Federal Land of Austria. It extends into the Pannonic lowlands and hills, into the extraalpine mountain region of the Bohemian Massive and into the Alps (Schneeberg 2076 m). The summer climate is warm and dry in the Pannonic region, cool and dry to moderately humid in the extraalpine mountains, and cool and humid in the Alps. Thermophilic oakwoods form the climax associations of the Pannonic lowlands. In addition edaphic variations cause the occurrence of steppe associations. The higher altitudes of the Pannonic region (from about 250 to about 400 or 500 m) and the prealpine hills are covered by the Querco-Carpinetum s. l., which, however, already contains Fagus sylvatica in most of its subassociations. Above 400 m beech forests dominate, admixed with fir (Abies alba). Fir occurs with differing densities but generally becomes more abundant at higher altitudes. Spruce (Picea abies) is added at still higher elevations in the mountains. This species forms pure stands at the upper timber line. The extra-alpine mountains do not extend high enough to form a timber line. Pure stands of spruce do not occur there except under the influence of edaphic factors (peat-bog rim stands). Above the spruce belt of the Alps there is an additional belt of Krummholz, which in the Calcareous Alps is composed mostly of Pinus mugo, while Alnus viridis dominates in the Central Alps. The uppermost zone of the Calcareous Alps is occupied by Caricetum firmae. In contrast, the Central Alps, which reach only comparatively minor altitudes in Lower Austria (Hochwechsel 1743 m) are wood-covered. An exception is the summit itself, which is occupied by Loiseleurietum. Extrazonal permanent associations (Dauergesellschaften) of importance in the mountains are pine woods on steep silicate and dolomite slopes. They are dominated by Pinus sylvestris in the extraalpine mountains. In the eastern part of the Calcareous Alps in Lower Austria Pinus nigra occupies a small rim along the eastern slope. Riparian forests of large extent have been preserved along the Danube and the March. Along the Danube they contain, especially in their softwood belt, many mountain-species, whereas the Danubian hardwoods and the riparian forests along the March are rich in submediterranean and continental species.