Inosculation... What example is this type?

I found these two trees on my property and did as much research as I could but I'm still unclear is what transpired within the oak tree Illustrated.... Right above the fuse area the oak trees bark and structure of the tree changed over to more like the pine tree...... Is this a genetic change moving upward or is this just a physiological change in which the pine tree has taken dominance in a hybrid fashion of the oak tree.... I'm really trying to understand this however I'm definitely not a scientist.

 

It is possible that there is some hormonal disruption--there wouldn't be a genetic change, though the presence of foreign or adjusted hormones could cause a different physical expression. For something analogous, look into witches' broom in plants.

 

Ok thank you