
These are three closely spaced Siberian elms (Ulmus pumila) growing in a row. The Siberian elm is an exotic species, originating from northeastern Asia. Rarely grown as trees, they were introduced to this country to be used as planting materials for hedges.
The trees in this yard most likely began their lives as a hedge, tightly planted in rows and trimmed with shears. At some point, the homeowner stopped trimming the hedge allowing the trees to grow unimpeded, quickly assuming their natural upright form.