Totally different trees. Callery pears are used because it is a 'fastigiate' tree. Is narrow and tall, but not much tall. Perfect for sidewalks. And is a tree f

Totally different trees. Callery pears are used because it is a 'fastigiate' tree. Is narrow and tall, but not much tall. Perfect for sidewalks. And is a tree for four seasons with splendid flowering and fall color. Many fastigiate trees split in this way all the time because the branching happens in very acute angles and this creates a weak point. Asimina and mulberry aren't good for sidewalks. Asimina is too short, parse and wide and spreads from the root. Mulberry is a tall tree, too big and too wide. Both made the soil slippery and a mess by fruits and leaves. A possible replacement could be young american hornbeam that can be pruned narrow for a long time before it opens wide. there is not a lot of candidates for a narrow sidewalk. Landscapers deal with this problems and try to fix it all the time.