Late Holocene vegetation changes and human impact in the Changbai Mountains area, Northeast China

摘要

Pollen analytical data from Jinchuan site in the Changbai Mountains, located within the mixed temperate broadleaved forest zone of Northeast China, were used for the reconstruction of vegetation changes and dynamics of human habitation activities in the last 6000 cal. years in the periphery to the Chinese civilization areas of former Manchuria. The beginning of the present type of vegetation dominated by mixed forests with the characteristic tree species Korean pine (Pinus koraiensis Siebold & Zuccarini) was dated to 3100 cal. BC. Expansion of Korean pine occurred in two steps. The second phase of enhanced expansion of pine along with other coniferous taxa of higher altitudes such as Abies and Picea was dated to around 70 AD. The pattern of Late Holocene spread of coniferous elements (P. koraiensis, Picea, Abies) and retreat of deciduous oaks was associated with phases of climatic cooling and presumably changes in effective precipitation. The oldest record of habitation processes identified in pollen assemblages from Jinchuan was dated to around 140 AD. The buckwheat (Fagopyrum esculentum) cultivation was documented since the first half of the 9th century AD. The 18th century immigration of the Chinese population of Han ethnicity was reflected in the fossil archive, due to economic activities of the settlers connected with exploitation of forest resources through cutting of pine trees, protection of walnut stands, and cultivation of Hordeum/Triticum cereals.