I'm no expert and certainly no bodybuilder but balance and periodicity is the key, assess what muscle groups you've worked through the day and if pumping iron is you're way to unwind, ensure you're not burning muscle groups you've already blasted through the day. Remember very few of us would work to momentary muscular failure in our work day that would be very dangerous!!
So there is substantial room after work to blast and pump those muscle groups (so long as your calorie intake and general diet is sufficient) if you apply a little common sense.
I wouldn't work forearms after a day of climbing for example, but I would work legs and chest.
If I was working as a groundie all day I'd probably avoid any lower back work, but tris and abs would be fine.
Also I'd strongly advise trying different forms of training, partial reps or matrix with lighter wieghts is good and can be maintained despite a heavy workload through the day. One last thing flexibilty is the key to everything we do in trees and even on the ground and your excercise regeme should include a good portion of streching and flexibilty work..really pays double up in the tree.
SF