I haven't noticed many acorns in my part of Northern Ohio. I have seen the squirrels scampering like mad to stock up on what they can an they are looking rather chubby these days also.

Interesting that I came across this thread. I was listing to NPR last night on my way home from work and they were talking about the acorn shortage. I beleive that person they were interviewing about it lived in Washington State. Either way, doesn't sound like it's a localized event.

I've been watching my yard, the squirrels have been storaging the acorns like crazy... that bothers me....

Maybe the acorn shortage will cause the squirrel population to morph into deranged carnivorous mutant cannibals.

Seriously though...

Some things which could cause such a widespread phenomenon are:

Climate change
Widespread chemical contamination
Radiation exposure
Parasite infestation

Radiation and/or chemicals seem (to me) to be the most likely culprits.