THE HORIZONTAL ZONATION DISTRIBUTION OF VEGETATION IN HENAN

Henan is located in the eastern part of China, lies 31°23′—36°22′NL,110°21′—116°39′EL.It is about 167074 km² in area. The topography consists of plains, hills and mountains. The eastern part is the southern part of Huabei plains. The western part is mainly mountainous region which range from 1000m to 2000m above sea level.In summer, the climate of Henan is controlled by the summer monsoons coming from the Pacific Ocean. But in winter it is influenced by the cold air coming from Siberia. The vegetation of Henan hasa law of geographical distribution from north to south closely related to climate. The types of vegetation are different in different latitudinal zonations.The vegetation in the northern part belong to the temperate deciduous broadleaf forest region. The representative vegetations are the deciduous broadleaf forest and the evergreen needleleaf forest in the mountainous region. For example, Quercus variabulis forest,Quercus aliena var.acutiserrata forest and Pinus tabulaeformis forest, Pinus bugenana forest, etc. On the plains of eastern part, winter wheat, maize and rice are planted two crops a year, or winter wheat, cotton, maize, sesame and sweetpotato are planted three crops in two years. on the sandland, winter wheat, sweetpotato, peanut and sesame are planted oncea year. The mixed evergreen broadleaf forest and deciduous broadleaf forest which belongs to the subtropical evergreen broadleaf forest region cover the southern part of Henan. The representative vegetations are Quereus variabulis,Quercus aliena var.acutserrata and a few evergreen broadleaf trees, for example, Cyclobalanopsis glanca, Chclobanopsis myrsinaefolis, etc. The evergreen needleleaf forest consists of Pinus massoniana, Pinus taiwanensis (higher than 700m above sea level)and Cunnunghamia lanceolata etc.The climate in the eastern part of Henan is moister than that in the western part. In eastern part, the vegetation on the Dabie Mountain is characterized by Pinus taiwanensis and tea plantations. In the western part, however, there are no Pinus taiwanensis forest and tea plantations in Tongbai Mountain region.