In the southeast area east of Yunnan-Guizhou Plateau and south of the Yangtze River, hills and landforms are the most widely distributed and concentrated, which are collectively called "southeast hills". Among them, those located south of the Yangtze River and north of Nanling are called Jiangnan hills; South of Nanling, Guangdong and Guangxi are called Guangdong and Guangxi hills; East of Wuyi Mountain, in Zhejiang and Fujian provinces, it is called Zhejiang-Fujian Mountain. The southeast hills are located in the subtropical zone, rich in precipitation and heat, and are the mountainous areas with great potential for the development and utilization of forest, agriculture and mineral resources in China.