Malus:
Bark on young trees is reddish grey with conspicuous pores (lenticels).
http://canadiantreetours.org/s...
If the tree had been cut back then it would produce multiple new trunks. I'm not sure 15 years would be considered young if it hasn't been cut back.
If it is Crabapple ‘Adirondack’ we don't know it's parentage, this tree is a well used variety in Chicago so it's not far away.
It seems crabapples do have bark like this, look at the bark on Malus 'Pink Spires'..
http://www.smith.edu/gardens/b...
