Anthropogenic mountain forest degradation and soil erosion recorded in the sediments of Mayinghai Lake in northern China

The late Holocene vegetation of the Loess Plateau in China was influenced by both climate change and human activities, however, details of how humans modified the vegetation are unclear, especially in the mountain region of northern China. In this study we used pollen and charcoal analysis of a radiocarbon-dated sediment core from Mayinghai Lake, in northern China, to reconstruct the history of vegetation change and burning over the past 4500 years. Four stages of vegetation change are documented: 1) During 2500 BCE - 600 BCE, the vegetation was forest steppe, dominated by Betula, Quercus, Pinus, Artemisia, Poaceae and Amaranthaceae. 2) During 600 BCE - 1050 CE, there was a slight decrease in tree pollen representation with evidence of more intense human disturbance, especially during 600 BCE - 200 CE. 3) During 1050 CE - 1500 CE, tree pollen frequencies decreased rapidly and then increased again. 4) After 1500 CE, the tree pollen frequencies decreased to their lowest level within the sequence, and the vegetation was steppe, dominated by herbs such as Artemisia, Poaceae and Amaranthaceae. An increase in cereal-type Poaceae/Poaceae (CTP/P) ratio, charcoal and Humulus pollen from 950 CE onwards indicates increased human impacts in the area, associated with early deforestation as a result of intensified agricultural activity during the Northern Song dynasty. Additionally, much higher sediment accumulation rates resulted from deforestation within the lake catchment. However, after 1400 CE, the forest was largely cleared, partly for agriculture, and the climatic cooling of the Little Ice Age (LIA) likely also inhibited forest development. Regional warfare may also have contributed to the reduction of the regional forest vegetation during the intervals of 900 CE - 1000 CE and 1400 CE - 1650 CE.

Automated summary

The study reveals that the vegetation in the mountain region of northern China has undergone four stages of change over the past 4500 years, with significant impact from human activities. After 1500 CE, there was a drastic decrease in tree pollen frequencies, leading to large-scale deforestation, possibly due to intensified human activity and cooling climate.