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Postglacial evolution of forest and grassland in south edge of Gobi

Tree and grass coexist in south edge of Gobi, northern China. In this region, forest plays an important role in windbreak and sand fixation, and grassland is the foundation of animal husbandry. Afforestation can improve the environment and regulate the climate, but it also restricts the animal husbandry by reducing grassland. Based on robust method for tree and grass cover reconstruction with 19 000-year-long pollen records from northern China, we show that, the past tree cover peaked during the early Holocene (30.7±12.3%), and grass cover was generally stable (45.3±3.9%). Temperature, precipitation, tree-grass competition and fire had driven the postglacial evolution of tree/grass cover, and forest can suppress grassland by tree-grass competition when tree cover is higher than 13.8%. Our study provides implications for weighting between afforestation and grassland protection.