一、引言我国地理位置,南达北纬3°52′(即曾母暗沙以南)、北抵北纬53°31′(漠河)、西自东经73°40′(乌孜别里)、东至东经135°2′(黑龙江与乌苏里江合流处)。全国领土总面积约960万平方公里,其中,90％以上的土地处于寒来暑往、四季分明的温带和亚热带,10％以下的土地属于终年无霜、冬夏长青的热带。如此优 I. INTRODUCTION The geographical location of our country is 3 ° 52 ’north latitude (ie, south of Zeng Mu shisha), 53 ° 31’ (Mohe) north latitude, 73 ° 40 ’east longitude (Uzbekistan) from the east, Longitude 135 ° 2 ’(Heilongjiang and Wusuli River confluence). The total territory of the country covers an area of ​​about 9.6 million square kilometers, of which over 90% of the land is in the warm and cold season with four seasons and the land below 10% belongs to the year-round frost-free tropical evergreen and evergreen. So gifted