The Riss-Wurm interglacial from West to East in the Alps: an overview of the vegetational succession and climatic development

The vegetational and climatic developments during the Riss-Wurm interglacia l in the area on the northern flank of the Alps are reviewed. Reforestation seems to have begun over the whole region with a dwarf-shrub and ensuing s hrub phase, leading to birch and/or pine woodland. The rise in summer tempe ratures, which delta(18)O values suggest to have been a two-stage event, pe rmitted the immigration and expansion of more demanding trees (elm, oak, li me, ash, ivy,hazel, yew, etc.). Following the thermal maximum, which took p lace during the hazel and yew biozones, hornbeam dominated the forests in t he alpine foreland, whilst fir/spruce forests formed the dominant vegetatio n at sites closer to the Alps or at a higher altitude. A marked climatic de terioration can only be recognised towards the end of the interglacial, whi ch led to extensive spruce/pine and, finally, almost pure pine forests.