Treadmill 3.4 mph 15% grade for 2 miles (35 minutes +/-).
The only good workout involved with cutting firewood in my opinion is sustained maul and axe swinging: arrange as many rounds as you can on end in a tight pack, put on some good, stiff, full grain leather boots that allow you to stand on anything while protecting your feet and shins against shrapnel, and go to town. You'll be swinging from overhead and sidearm as the halves and quarters fall against each other, and as you scramble over the split pieces to swing at the next ones. This is big work, especially if you can't get the halves to split with an axe and have to use a maul. It's not dangerous if you're not an idiot, and you make sure your feet are set before each swing. Saves a lot of handling work as well. Try to swing continuously and effectively for ten minutes - it's a gasser. Trouble is, for the 3 cords I burn per year, the splitting is done after maybe one solid hour (not including rest breaks, which are many...) of splitting like this. This is good Lat and abdominal work - as good as anything, particularly if you're having to put full effort into a 6# or 8# maul to get the big rounds halved or knotty/twisted halves quartered.
