白榆(Ulmus pumila L.)是北温带落叶乔木。我国的白榆分布面积约占世界白榆的3/4以上,它是华北、东北、西北及长江以北广大地区主要造林用材树种。白榆具有速生、材质好、抗逆性强,尤其耐干旱、耐瘠薄土壤的特性。它是宁夏的乡土造林树种,是本区营造防护林、用材林和四旁绿化的优良树种。我所于1980年开始较系统的进行了全分布区的种源选择试验研究工作。通 Ulmus pumila L. is a north temperate deciduous tree. China’s elm distribution area accounts for about three-fourths of the world elm, it is in North China, northeast, northwest and the vast majority of the northwest of the Yangtze River afforestation timber species. Ulmus with fast-growing, good material, strong resistance, especially resistant to drought, barren soil characteristics. It is Ningxia native afforestation tree species, is the region to create shelterbelts, timber and green trees around the fine tree species. In 1980, I began a more systematic study of provenance selection in a fully distributed area. through