Spätglaziale und holozäne Florenund Vegetationsgeschichte des südlichen Mendelkamms, Südtirol ( Provinz Bozen, Italien)

A peat bog section of 400–620 cm depth has been pollen analytically investigated. It comprises a period from ca. 15.600–ca. 5.480 cal yr BP, i. e., the end of the Oldest Dryas chronozone to the onset of the Subboreal chronozone. During the Late-glacial warm periods of the Bölling and Alleröd chronozones, the reafforestation started with pine (Pinus sylvestris/P. mugo) forest steppe with common birch (Betula pendula, possibly partly with B. nana), Artemisia, Juniperus, and Hippophaë. At the forest limit, Swiss stone pine (Pinus cembra) and European larch (Larix decidua) were probably present. Ephedra, Chenopodiaceae and Poaceae formed a rock steppe vegetation. During the Younger Dryas cold phase, a short recession of pine forest and a revival of steppe vegetation has been recognized. During the onset of the Holocene (Preboreal chronozone), pine forest reached its maximal range. At the transition Preboreal/Boreal, the coniferous forest vegetation changed basically after immigration of Norway spruce (Picea abies) in the montane belt and because of the spread of mixed oak forest (with Ostrya) in the colline belt. During the Boreal chronozone the maximum range of hazel (Corylus avellana), Scots pine/mountain pine (Pinus sylvestris/P. mugo) forest and mixed oak forests (with Ulmus, Quercus, Tilia, Acer, Fraxinus excelsior) recessed in advantage of the newly immigrated Norway spruce forests which reached its maximal range in the montane belt.
At the transition from the Boreal/Older Atlantic chronozone silver fir (Abies alba) and beech (Fagus sylvatica) immigrated. During the Older Atlantic, silver fir and Norway spruce forest dominated in the montane belt, whereas mixed oak forest declined, probably due to shade concurrence of silver fir and beech. Later, during Younger Atlantic, Scots pine/mountain pine, Swiss stone pine and European larch were again more abundant compared to Norway spruce, silver fir, beech and mixed oak forest, presumably because of a cooler Holocene climate oscillation. The youngest peat bog section, probably the onset of the Subboreal period, gives evidence of a montane silver fir-Norway spruce forest close to the peat bog zone (more stomata of needles). At the forest limit Scots pine/mountain pine were growing with Swiss stone pine and European larch. The present montane beech-silver fir forest of Oberfennberg established later, during the younger Holocene.