I've not seen one of these before in the woods around here. This really stood out when I saw it. I don't think its fully grown. Its about 25' tall and the largest trunk (it has lots of rooted suckers) on it is about 6". The larger leaves are over 12" long. We've had temperatures in the teens so apparently its not going to drop its leaves.
From what I've read Magnolia grandiflora leaves are from 5 to 8 inches long. These leaves are easily to 12 inches.
Species is polymorphic. Different individuals produce leaves that can be short or long, narrow or broad.
I have read where unusual fall weather disrupted normal development of the abscission layer in ornamental pears here in Ohio...could this phenomenon be the reason for this tree's leaf retention?