Palynological and lithological investigations of three representative peat bog and wetland sites have been carried out in the upper catchment area of River Hardau (County of Uelzen). As indicated by ¹⁴C analysis, peat growth started around 4000 years BP in the Hardau source area. This study is reflecting vegetation development from the Subboreal to the Subatlantic. Human impact on the environment in the investigated area is already evident at 4000 years BP. Temporary expansion of heathland as a consequence of agricultural land use and woodland pasture has been demonstrated to occur during latest Neolithic period, at the beginning of the Bronze Age and in mediaeval times. Late mediaeval land reclamation is reflected by increases in the pollen curves of cultivated plants and other taxa, including grasses, indicative of human activity. High frequencies of micro charcoal and increases in Calluna, Secale and Centaurea cyanus pollen at the transition to modern times, herald the beginning of an intensive heath culture accompanied by so called "eternal" rye growing, plaggen agriculture and the spread of heathland. Reafforestation with conifers and the establishment of crop rotation farming of the 19th century are well represented in the pollen diagram of Hardauquelle (source of river Hardau). In the valley of the Olmsbach creek, an intense local impact on the flood plain has been demonstrated palynologically for the first time.