Climate And Human Impact On Vegetation In The Upper Part Of The Ussuri River Basin In Late Holocene, Russian Far East

Changes   in vegetation  in the southern  Sikhote-Alin  Mountains,  which are in the upper reaches of the Ussuri  R., are shown respond to minor climatic fluctuations over the past 5.4 ka. The largest mountain,  Muta mire,  chosen for  paleoenvironmental reconstructions,  is located within the main regional  watershed.  The studies include diatoms  and pollen analyses.  Chronology is based on radiocarbon  dating and position of B-Tm tephra of the Millennium  eruption of Baitoushan  volcano.  The cooling and warming reconstructed from the regional data correlate with global paleoclimatic events. The regional  humidity  changes notably  along with the temperature  fluctuations.  Fire chronology was established and its significance  for vegetation was estimated. Periods of frequent  forest fires coincided  with reduced moisture supply during cooling events. The analysis per formed revealed a considerable human impact on the vegetation in the 20th century.