Warren in Lancaster, PA
In Pennsylvania we call sorbs "mountain ash". It is not really an ash. Our native mountain ash is found in the Appalachians and the northeast part of the state. I have seen it in Berks County also.

We also have a European mountain ash, Sorbus aucuparia which is widely planted in yards. It is a small tree with clusters of bright red berries which persist into the winter and attract birds.

The sorb that Jerome is talking about Sorbus domestica is a favorite for planes in France. You might remember seeing a Goldenberg plane with a screw mechanism so you can adjust the cap iron without taking the wedge out of the plane. They are usually made of this sorb which the French people call cormier.