Alternative vegetation states on the Loess Plateau and implications for large-scale afforestation success - Li Ma; Xuan Li; Xingchao Xu; Liping Yang; Qinqin Chang; Siqing Wang; Chao Guan; Miaojun Ma; Chi Xu; Yanchuang Zhao; Emilio Guirado; Ning Chen; et al. (Proceedings of the National Academy of Sciences, 2026)