I always thought those brooms with a ring of horizontal branches looked unnatural. Looked artificial. Broom is a very natural shape for elms, maples and many deciduous broadleaf trees. Walk through a forest and look at the shape of the trees. The elms in particular will be these lovely wine glass shape, the tall wine glass, rather than the wide brandy balloon shape. Other species often the informal broom plan with 1, 2, 4, 8, 16, 32 branching, where the 2 and 4 are really sub-trunks, and the 8 and higher are gently arching up and out.
Interesting note, elms will usually have the main single trunk be moderately long, each subsequent segment is shorter. In maples especially the 2,4,8 etc plan, the first segment is short, then the second segment is long, the each segment afterward is progressively shorter.
Take a drive, walk or otherwise get outside and look at trees, and you will see what I mean. Look at the deciduous broadleaf trees, there are far more brooms (especially informal brooms) out there than any other form.