Thanks for the sound advice Hills, after three days of working at getting the planks loose I'm ready to abandon the project. The farmer put in way to many cross support bracing not easily accessible and the upper edge is still attached to a wall

If today's plan does not work, I'm going to drop a long cable through the top end between planks then attach that end to the truck big loop hopefully as I drive out the cable will rip out the braces.

I only need six planks eight feet long to complete my garage project at home so its no big deal to abandon the rest.

I'm insulating my garage with paneling and better lights in preparation of opening a small fix it shop.