Bibliography: D Walker


The Plant Geography of Yunnan Province, Southwest China


Late Pleistocene and Holocene Vegetation History at Xi Hu, Er Yuan, Yunnan Province, Southwest China


Abstract: Pollen diagrams from a swampy lake at 26?N, 100?E and 1980 m a.s.l. record the vegetation history on 1000 m of slopes above it from about 17,000 BP to the present day. The main stages are: 17,000-15,000 BP: montane conifers above, Pinus-evergreen sclero- phyllous Quercus below. 15,000-14,000 BP: montane conifers temporarily restricted. 14,000-10,500 BP: montane conifers above, evergreen and deciduous forests, Pinus forests and semi-arid scrub below. 10,500-0 BP: Pinus forests with evergreen broadleaved component dominating all slopes. Sediment stratigraphy and pollen analysis together suggest the following climatic sequence: 17,000-15,000 BP: cold semi-humid. 15,000-10,500 BP: fluctuating with some periods of intense seasonality, becoming warmer toward the end. 10,500-0 BP: similar to present sub-tropical monsoon climate. There is no certain evidence of climatic change after 10,500 BP. Although human settlement has probably been continuous since 3000 BP, often dense and associated with major hydraulic engineering works, the pollen diagrams do not show any clear indications of their impact on the vegetation; this is probably due to unsuitability of the investigated sites for this purpose. All the material studied is younger than the last glacial maximum (Dali stage) of Yunnan, and the Pleistocene-Holocene transi- tion is associated with the vegetational and climatic events described at about 10,500 BP.