what kind of tree is it? The leaves look like elms, so I once thought they were elms. But I happened to see a tree that said "Elm". Look!

This is another kind of elm belonging to Ulmus of Ulmaceae. Pay attention to its bark, so it has other nicknames-Ulmus pumila (Compendium of Materia Medica), Ulmus pumila (picture of common trees in Hebei), Ulmus pumila, Ulmus pumila (Henan), Ulmus pumila (Shandong), Ulmus pumila, Ulmus pumila (Jiangsu), and Red Chicken Oil (Taiwan Province).