Based on this,we drew such a conclusion that the salt -and-drought tolerance of three varieties was in order of rock elm > southern rock elm > U.pumila.

• 3 种榆树的耐盐性排序为:岩榆>南方岩榆>白榆:3 种榆树的耐旱性排序为: 岩榆>南方岩榆>白榆。