I was an idiot for not realizing.
Those leaves do not look like Oak Leaves. They should either look like Red or White Oak.
Red Oak leaves have pointed ends.
White Oak Trees have rounded ends.
Also, draw some acorns, so it feels like we're looking at an oak tree.
I love the way you made the bark, but do improve on it, so it feels even more like bark off a typical Oak.
Edit: Wait a minute, I've had this thought for a while.
Is this NFWar's Blood Oak Tree
texture? If it is, you should give him credit.