You can then grease the skirts when the nuts are about ready to keep the squirrels from climbing the tree to get them. That won't do much for when they fall to the ground though, unless they are low enough when the first ones start to fall you can use a long pole and beat the others to make them fall so you can harvest them.
I've had to kill squirrels in my attic before. I use mouse decon for that. It has something they like to eat, but also warfarin to keep them bleeding internally and ground glass to get it started. You can also hang some rat traps on the tree with peanut butter, preferably ladder high to keep people and especially kids from getting hurt.
When I first moved in here in 88', I planted 3 pecan trees. A Chataw a Navaho and a Desirable. The're all medium big trees now. About 30'. They're all grafted, meaning that they have native root systems and eatin' pecan tops. The nuts are huge. 6 or 8 from any of them is a meal. They're big and buttery and delicious
But I don't get any. The squirrels eat them ALL green. Right out of the husks. I'm in a subburban neighborhood so I can't shoot them. I'm a bit scared to put poison out because of the pets and the kids.
Every year I see these giant pecans forming, and then like over night there's a neat pile of husks and shells. I'm thinking squirrel teriyaki might be good with pecan sause.
I need help. What kind of traps do I get? When do I set them? How many do I need? Any recipies? The skinning and cleaning I think I can handle.
I'm serious here. Help me.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic