Tree planting in western canada is the complete opposite of office work. Instead of too little exercise, you'll have a broken body. From what I've heard, it's brutal work where you're paid by the tree and not by the hour. Not my cup of tea.
Yes, I suppose one gets paid by the tree pretty much everywhere. Many planters do say that after max 7-8 seasons you're broken. But -- to me, many of them seem to take this work too seriously. If you're paid by plant, why not take it _a little_ easier?
I've only planted in Estonia thus far and survived well, though. I seem to have suitable bodily proportions for the job, but it also comes down to planting ergonomically as wisely as you can right from the start. In particular, learning to use both of your hands and legs equally (plant "ambidextrously" as they call it). See this thread from replant.ca, an awesome resource for tree planters in Canada:
http://www.replant.ca/phpBB3/viewtopic.php?t=65984
But, sure, it is tough work to the point of not being sensible to many.
