How much might a tree that was already old change in 70 years?

Suppose you were returning to a location after 70 years and seeking a particular spot marked by a very large old oak tree. Let’s say the tree is still standing, is healthy, and has not lost any of its main branches. The landscape all around it has changed considerably. There are numerous other oak trees in the area, but you have to find a certain one that you once knew very well.

How recognizable would the tree be after seven decades? How much the same might a tree look that was already old before? Would you expect to be able to tell for sure that it was the same tree, or could it have changed so much in that time that you might not know it?