I have noticed that sometimes the calls seem to impede more than help. But, the converse is also true. Give it a try with out calling....just to see what happens.
As for the oak/beech/hickory stands, it looks like you've got a prime spot. In the late part of the season, you've got to have a slow, very quiet approach to the area. With no leaves on the trees, they'll see you (and hear you) coming a mile away.
Also, look for the nests; the ones made of sticks and leaves. They are considerably larger than bird nests. If you've got nests, you definately got active bushytails. If there's no sign of nesting, I'd move on. In the colder climates, they seldom use nests in the winter (prefering hollowed out trees), but the nests will remain from the previous summer. The nests are very resiliant to weather, and sometimes will remain for years. I've seen it!
Good luck willis
Texas Squirrel Hunter :gulp: