The impact of early smelting on the environment of Huoshiliang in Hexi Corridor, NW China, as recorded by fossil charcoal and chemical elements

Recent research has greatly increased our knowledge of early human impacts on the environment. Records of fossil charcoal and chemical elements from a bronze smelting site at Huoshiliang, in the Hexi corridor of northwest China, provide material with which to estimate the extent of smelting activity and its impact on the environment. Analysis of the microstructure of wood fossil charcoal is used to identify the types of charred wood and to reconstruct the local vegetation present during the period of smelting. Four wood types were used as firewood for smelting: Tamarix, Populus, Salix, and Polygonaceae. The assemblages of fossil charcoal showed that Tamarix was the most dominant shrub and was widely used as firewood, as a percentage of charcoal it increased from 89% to 97% over the smelting period.</p

Early agricultural development and environmental effects in the Neolithic Longdong basin (eastern Gansu)

Neolithic agricultural development and environmental effects in the Longdong area were reconstructed using a synthetic approach, investigating pollen, charcoal, and seed remains for two cultural layer sections and five flotation sites. Results show that Neolithic agriculture in the Longdong area had a simple organization and was dominated by the production of common millet, especially in the early and middle Yangshao age. After the late Yangshao age, Neolithic agriculture developed into a more complex structure, dominated by both common and foxtail millet and the cultivation of rice and soybeans. The production of foxtail millet gradually increased through the Neolithic period, reaching its highest point during the Qijia culture. Soybeans were first cultivated during the late Yangshao culture, approximately 5000 cal a BP. Rice production began no later than 4800 cal a BP, and continued to exist in the Qijia culture, approximately 4000 cal a BP. Agricultural production in Neolithic Longdong, specifically in the &quot;Yuan&quot; area of the loess plateau, developed as a shrub and grass dominated landscape. Vegetation in the river valleys was partly covered with Picea, Tusga, and Quercus coniferous and broadleaf mixed forests. Agricultural activity during the Neolithic period caused an increase in farmland on the loess tableland and a decrease in the abundance of shrub and grassland in the Longdong area. When farmlands were abandoned, vegetation recovered with Hippophae-, Rosaceae-, Ephedra-, and Leguminosae-dominated shrublands and Artemisia-dominated grasslands.</p

Land degradation during the Bronze Age in Hexi Corridor(Gansu, China）

Pollen and charcoal analysis, with high resolution AMS C-14 dating, on two sediment sections in the Hexi Corridor track the process of settlement development and abandonment during the Bronze Age. The evidence shows that agricultural activity during the Bronze Age caused an increase in farmland and a decrease in the abundance of Artemisia grassland in the Hexi Corridor. Land degradation is probably the main cause for decreased agricultural activity and settlement abandonment. Agriculture- induced soil fertility loss and land salinization contributed to the process of land degradation. However, increasing climate aridity around 4000-3500 cal BP is probably the main initiating cause for the contraction of arable land and vegetation degradation in the Hexi Corridor.</p