Where have the acorns gone?

The Washington Post has an interesting article talking about how there appear to be no acorns falling from the trees in all of Arlington County (Virgina) this year. While some say it's an alarming indication of the effects of global warming, others say it's nothing to worry about. I grew up in an area full of oaks and come to think of it, I haven't seen any acorns at my parents house this year. Weird. (And poor squirrels!)