ИСТИНА

The last hundred years of land use history in the southern part of Valdai Hills (European Russia) were reconstructed on the base of high resolution pollen data from the peat monolith taken from the Central Forest State Reserve supplementing with historical records derived from maps of the General Land Survey of XVIII and XIX centuries and satellite images. According to created age-model, provided by dating using radio-nuclides 210Pb and 137Cs, pollen data of the peat monolith allow us to reconstruct vegetation dynamics and human induced changes during the last hundred years with near annual time resolution. The obtained data showed significant variations in the pollen values of main tree species (spruce, pine and birch) that are associated with both changes in pollen productivity of these tree species in different years, and with forest successions after clear cutting. Despite the location of the studied peatland in the center of the forest area and rather far away from possible fields and hayfields, the pollen values of plants – anthropogenic indicators (Secale serale, Centaurea cyanus, Plantage major/media, Urtica, Rumex, etc) are relatively high in the period since the beginning of the 20th century to 1970th, especially in the peat horizon formed after the Second World War. In the late 1970th – early 1980th of the pollen of cereals gradually disappeared from the assemblages, the quantity of pollen of other anthropogenic indicators are also significantly reduced, which reflects the overall processes of the agriculture decline in the forest zone of former USSR. The studies of micro-charcoal concentration in peat samples revealed an increase in the proportion of micro-charcoal remains in the peat layer that had accumulated during the Second World War. The highest concentrations micro-charcoal particles were observed in samples of peat, accumulated the 1960th to the 1990th, and probably reflects the use of brown coal as fuel in the region. During the last twenty years the industry and agriculture in the territories adjacent to the Reserve fell into decay that was reflected in compositions of pollen assemblages.