ENTS,
I don't know if any of you can answer this question, but it's worth a try.
Blackjack Oak, Quercus marilandica, is one of the many common species of oak, here in the NJ Pine Barrens.
 
On the "Bay" golf course at work, there is a Blackjack Oak tree that has tiny leaves. I have attached a photo of some leaves from my oak leaf collection. The tiny ones (and the slightly large one on the far right) come from that tree I'm referring to, while the huge one is a little bit larger than average for the species. The one on the far right is as big as they get on that tree, while the tiny ones are more normal for that tree.
 
My question is, why would this one particular tree have such tiny leaves compared to all other trees of the same species? It's the only Blackjack Oak I've ever seen with tiny leaves. One idea I thought of was poor soil. But nearly all soil in the pine barrens is poor.
 
I've also found that oak saplings seem to have larger leaves than mature trees. But Blackjack doesn't seem to be that way. This tree may be 40 to 50 feet tall, and may have a DBH of 15 feet, if memory serves. All other Blackjack Oaks, no matter how big and tall, have big leaves.  Any ideas?

The huge leaf in the middle of the picture is 5.5' X 5.5".

Before leaving work today I went over to that oak tree and took pictures of the bark, the entire tree and some of the leaf canopy, to give you an idea of what it all looks like.
 
Being where it is, this tree, and the golf course its on, are at the very eastern edge of the pine barrens. In fact this golf course was built in and on the edge of the "meadows", or salt marshes. Next to the meadows is the bay, and then the islands of Brigantine and Absecon , Absecon Island being the one that Atlantic City is on.
 
Anyway, does this look like water oak or blackjack oak to you? I always assumed it was blackjack oak, except that the tiny leaves make me a little doubtful. Notice that all the leaves are tiny, not just a few of them.
 
I'm guessing that the DBH is in the 24 to 30 inch range, and the height might be 40 feet. The golf course was built in 1914, and the tree I'm guessing was already there, and possibly very young. It's pretty close to one of the fairways, maybe 30 feet from it or less.
 
While out there I saw again the stump of the giant red cedar they took down last year. It's such a shame they took out a state record tree, just because they have a dislike for red cedars. Unbelievable.
Barry