Hello Mr Inlay. Let these guys tell you how to work that pile, and I'll give you a caution from another perspective. I think you're a player, so in addition to protecting the rest of your body, here are a few thoughts for your hands. There was a summer or two I HAD to work on downed trees in the yard. I used my hands as vises - Big Mistake. There was no injury "event", but I played some pretty painful gigs until I put 2+2 together. I had to switch to handling all lumber with open palms before it got under control, and it's still with me today (I have a hand budget I must stick to). I'm a lot older than you, but this stuff adds up.
When you get to work of this scale, Repetitive Stress Injuries (RSI) are possible. I got what I think is Tennis Elbow from holding two buttons on my little electric splitter for hours and hours, so I had to rig up a hands-free system. What a relief.
The back is the thing that we all worry about, but I'll say if you have some small issue at the end of a shift, try to multiply it by 100 or 1,000 over 4-5 years and make corrections tomorrow. It's quite an eye-opener when you go to pick up a cup of coffee and scream!!