In my area of Southern California, most of the firewood available is very hard wood, e.g., eucalyptus or oak that is incredibly difficult to split with an axe. Tried out this inertia wood splitter on my last trip. Set a 6.5 inch diameter or less piece of wood into the splitter and a couple of blows from a 3-5 pound sledge and even the hardest wood splits like butter. Works great! My axe slinging days are over!
https://www.amazon.com/Inertia-Wood-Splitter-Manual-Sharp/dp/B07B3S9C3L
https://www.amazon.com/Inertia-Wood-Splitter-Manual-Sharp/dp/B07B3S9C3L