these leaves do not follow the rules - tree ID help

okay - I have seen thousands of post oak/blackjack oaks/water oaks where I hunt. Yes I'm a traditional bowhunter so I move like a turtle and exam every square inch of everything in eyesight - and I am a tree geek. That said according to my book "National Audubon Society Field Guide to North American Trees - Eastern Region" these leaves should not exist! First up is either a blackjack oak or a water oak, but regardless - neither of these trees has a leaf eight inches long! BTW of all the hundreds of acres I hunt, the trees producing these mutant leaves grow in one tiny area. Next up is a post oak ( I think) with a leaf nine inches long! Again, in this same tiny area. According to the book, blackjack oaks are 2-1/2 to 5 inches. The second leaf post oak should be between 3-1/4 and 6 inches. Regardless no oak tree growing around here should have leaves that big. Any thoughts?

Leaves are very variable in size. Often, black oaks will have huge leaves just like that on stump sprouts or young trees that are totally different than the mature foliage. Often, the leaves are bigger in shaded areas, too, and if they're growing fast in fertile soil, they will put out bigger foliage. Not that out of the ordinary.

NCHillbilly said:

Leaves are very variable in size. Often, black oaks will have huge leaves just like that on stump sprouts or young trees that are totally different than the mature foliage. Often, the leaves are bigger in shaded areas, too, and if they're growing fast in fertile soil, they will put out bigger foliage. Not that out of the ordinary.

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Yes! The area where both these trees were growing (and other huge leaved oaks) is a very very shady slope but there's one wide sandy trail providing the only sunlight. Maybe the conditions are just right for them to grow unusually big leaves. The book never mentioned this!

On many different species of oaks the leaves on the lower limbs will be larger and of a lightly different pattern than those on the upper limbs.

Looks like post oak to me.

Black oak. Look on the underside of the leaf, should be a little fuzz in the webbing depressions, usually rusty colored but sometimes more creamy whitish in nature.
No dendrology book can cover all phases and variations on native trees and still be carried in a backpack. Too many environmental influences in the micro-ecosystems to document them all in a small totable book.

ps - Ma Nature doesn't read the book.