Question
We live in Central North Oklahoma and have 10 Pecan Trees in our front, side and back yards that all produce.  Love the Pecans, but their shade is making the yard very bare. What can we grow in their shade that doesn't make it difficult to find the nuts when it's time to harvest.

Answer
My great-grandfather grew Pecans in Claremore, Oklahoma.  Sadly, I don't think anything will grow under these heavy-shade conditions and still be able to walk on them and find the nuts at harvest-time.   Great grandpa had wispy lawn (probably what you have as well) that was a danger to mow, because of the nut husks being thrown by the mower.  Still, turf could be tried with caution as it will compete with the Pecan's roots for the water and nutrients.

http://www.detnews.com/apps/pbcs.dll/article?AID=/20090410/OPINION03/904100302&i...

The Pecan, unlike the Walnut, doesn't produce root toxins that will kill turf, but the shade is a real obstacle to plant growth...So, maybe a PAVER patio (so water can penetrate to the roots).  And one that you don't mind sweeping, because Pecans are always dropping something!  Maybe a nice hedge outside the drip-lines, too.  

http://en.wikipedia.org/wiki/File:EvermanPark.JPG

If you need help with additional Pecan questions or problems, here is a good resource:  
http://aggie-horticulture.tamu.edu/fruit/pecan1.html

~Marc