As others have said, wear long pants and carry a stick. Further, be alert and keep your eyes on the trail, not your GPSr. I was returning from a cache in Raleigh and was fiddling with the GPSr while walking and almost stepped on a large black snake. (Non-threatening, beneficial snake, but still would dislike being trod upon.)
So simply be aware and poke around the underbrush before stepping or reaching and you'll be ok.
--Squishy