Don't understand the deep litter method - LOTS OF ISSUES

[Tacswa3]

I have some questions...
1. Can I use cedar shavings and pine shavings on plywood floor of the coop with deep liter?
I use a little bit now, but clean the coop out weekly, and the floor is damp... Won't the flooring rot?
2. I rake pine needles for the run, only have a small amount now, waiting for the tree to drop more. Can I add cedar and pine shavings in the uncovered run without it caking?

I'd stay away from cedar shavings. Cedar contains a natural toxin and be bad for animals. Every animal is different, it may not bother some but will others.