Mostly it's important to get the wood 8-12 inches above grade on a material that termites can't/wont eat. That way you can inspect the pile regularly and break down the tunnels they build to access your wood.

You could construct a platform out of palettes and top it with sheet of tin. The termites will eat the pallets of course but the sheet of metal will prevent them from getting into the wood pile.

You could just make sure to get regular termite inspections. I have used pallets before and haven't had a problem. I don't know if termites are more prevalent in certain areas than they are in others, though. Definitely be careful because termites are awful to take care of if you get them.
http://www.berniespestcontrol.com/services