Pollenanalytische Untersuchungen im Robenhauserried (Pfaeffikersee/ZH) Ein Beitrag zur spaet- und postglazialen Vegetationsgeschichte im Zuercher Oberland 2. Teil: Postglaziale Floren- und Vegetationsgeschichte, menschliche Landnahme

摘要

During the early Holocene, thermophilous deciduous tree species (oak, elm, lime tree, maple, ash [mixed oak forest], hornbeam, hazel, beech) and conifers (silver fir, spruce) immigrated and spread out in the area of the Lake of Pfaeffikon, whereas the late glacial colonists Scots pine and birch recessed. During the Older Atlantic the mixed oak forest reached its optimal spread. At 6400 y BP beech and silver fir (and later spruce) spread quickly in the Pfaeffikon-Robenhausen area. During 5700 y BP (beginning of the Neolithic) occur the first signals of human impact on vegetation (culture pollen, forest clearing; during 5000 y BP lowest amounts of beech and silver fir pollen, more culture indicators). After the immigration of hornbeam during the beginning of the Subboreal, an intensified human presence has been recorded from the Bronze Age to Roman times: increasing amounts of pollen indicators which reveal farming, forest clearings, pasturing and trim of deciduous trees). At 3000y BP started peat growth together with the local silting-up of the Lake of Pfaeffikon; later on started the development to a raised bog. During Roman times, sweet chestnut and walnut were introduced. From 1715 to about 1960 peat was used as fuel At the drilling site ca. 1.5 m peat were removed; this corresponds to ca. 1300 years peat bog growth.