Question

how do american elm trees reproduce

Answer 1

Numerous species, or types, of trees are called elms. They belong to the family of plants called ulmaceous. In some cities in the United States and some countries there were a large number of elms, but during the 20th century a plague killed many of them.

Answer 2

The elms are those which are the  species, or types, of trees and they are in the family of ulmaceous. In US, they reproduce them through the organization of industries but most of these trees are killed by many in the 20th century due to human activities.