Abstract:Diversity of Quercus mongolica communities was investigated in 13 sites across northeastern China which differed in latitude, altitude and longitude. Field investigations were conducted. Measurements were conducted from the north edge of Q. mongolica range (Huma, Heilongjiang Province) to the south end (Baishilazi, Liaoning Province). The geographic position (including latitude, longitude and altitude) of each site was recorded, and plants in the tree layer (including all mature trees, saplings and seedling...