Charcoal evidence for environmental change ca. 3.5 ka and its influence on ancient people in the West Liao River Basin of northeastern China

Abstract

Abstract Fossil charcoals from archaeological sites provide direct evidence for the relationship between environmental change and ancient peoples’ livelihoods in the past. Our identification of 5811 fossil charcoal fragments from 84 samples suggested temperate deciduous and mixed conifer-broadleaved forests as the dominant vegetation at the Erdaojingzi site in northeastern China ca. 3500 cal yr BP; the major representative taxa were Quercus, Pinus, and Ulmus. Four woody plants probably supplied humans with food resources at the Erdaojingzi site, including Quercus, Ulmus, Amygdalus/Armeniaca, and Ziziphus. The nuts of Quercus were utilized as staple foods because of their rich starch content. The leaves of Ulmus may have been used by humans because of their massive dietary fibre. Amygdalus/Armeniaca and Ziziphus probably provided fruits for humans. Based on the coexistence approach (CA) used on the fossil charcoals, we found that the MAT anomaly was 7.9 ± 5.9°C at ca. 3500 cal yr BP, which is almost the same as the modern one (7.8°C), while the MAP was halved from 772 ± 301 mm at ca. 3500 cal yr BP to 370 mm currently. The wet climate might have facilitated significant development of rain-fed agriculture, promoted the emergence of large settlements, and eventually facilitated the birth of civilization.