If you're doing it for income, or to store enough wood to heat your home, you use the proper tools. A chainsaw and hydraulic splitter.
Chainsaw and hydraulic splitter isnt the entire equation.
I store and burn 4-5 cord a year. I also sell a few cord every year.
While a chainsaw is great for cutting logs to length, and a splitter is great for splitting into burnable sized logs, you still NEED at least one axe or hatchet, as well as a few other tools.
A machete, axe, hatchet, shovel, felling wedges, and a few 6" log rolling bars are all used during the felling and bucking a tree.
Finding a tree to cut down and use for heat is great, but they are hardly ever in a clear enough space to work efficiently and safely once they are down.
Quite often I have to use a machete to clear undergrowth, just to get to the base of the tree.
And after the tree is down, it is much faster and safer to handle any limbs smaller than 2" or so with an axe. Trying to clear those small limbs with a large saw is very dangerous, not to mention a waste of precious fuel if you are out for a day or more cutting.