Ziwuling region has developed with various vegetations of secondary forest in Loess Plateau. In different phases of development, vegetation systems in this region have changed from pioneer herbage species initially recovering in abandoned cropping lands (Bothriochloa ischemum, Artenmisia giradii and Stipa bungeana, Artenmisia sacrorum, Spodiopogen sibiricus and Sophora flavecens, Themeda japonica, and Arundinella anomala) to secondary shrubs (Hippophae rhamnoides, Sophora viciifdia, and Ostryops...