摘要: Tumen region is situated in the northwest of Yiyuan county, Shandong province, about 130 km to the east of Jinan city, the province captial. The geographical coordinates are 118°33′E longitude and 36°04′N latitude. The modern climate is a warm temperate monsoon forest type, with annual mean temperature of 13℃ and annual mean precipitation of 767 mm . The aridity is 11-- 3.0. So this region is the transitional environment between semiarid and semihumid