Its kind of hard to say. Going by BTU's gets problematic because it is hard to maintain a set temp when heating with wood. Around here if a house uses say 700 gallons of oil a year, it will therefore use about 7 cords of wood. In other words; 100 gallons of oil equals 1 cord. It is surprisingly accurate.
I have no intention of traveling from birth to the grave in a manicured and well preserved body; but rather I will skid in sideways, totally beat up, completely worn out, utterly exhausted and jump off my tractor and loudly yell, "Wow, this is what it took to feed a nation!"