Pollen records and vegetation and climate changes in Heqing Basin, Yunnan Province since middle Pleistocene

Abstract

Vegetational succession and climatic change since middle Pleistocene in Heqing Basin in Yunnan Province are discussed according to the sporopollen analysis for the top 155m length core and about 800 kaBP history from Heqing deep drilling core. This core is the first drilling core of Environmental Drilling Programme in Chinese continent. The results show that vegetation in the surrounding mountains in Heqing cathchment experienced many times changes among coniferous forest dominated by Pinus, montane coniferous and broadleaved mixed forest and cool temperate coniferous forest during the period about 800 kaBP to 6. 98 kaBP. From 6. 98 kaBP to today, vegetation has immensely changed, such as forest degraded quickly and vegetation dominated by herbs, when human activities have begun affecting vegetation. Human activities represent disafforestation and planting crops and so on. Climate corresponding to vegetation evolution may be divided into five stages and contains many times cool and warm, dry and humid gyrations since about 800 kaBP.