Simple. An ax is light, small, easy to pack/stow, uses no fuel, spills no fuel, has no moving parts to break/replace/maintain, and can live in a vehicle full time. Any newb can go out and buy a decent ax for wheeling and be able to clear fairly good sized downed trees over trails. I've had one in my trucks since my first wheeling adventures began. Used them countless times and with a good one, it's really not that much slower than a chainsaw if you actually know how to use it properly; cutting a V-shaped notch into the tree and working your way around the tree.
Just go get yourself a good Fiskars/Gerber Brand.
Indestructible, ridiculously sharp, and super light weight. Sears carries them as well as many other stores and you can find them in every variation/size imaginable. I have three; my first one, one for backpacking, and the big one that lives in the Jeep.
-"There's a Goo for that." -Me
-Words to live by; My goal in life is to be as good of a person as my dog already thinks I am.
-2001 Jeep WJ Ltd w/ Quadra-Drive; IRO 3" lift, JKS front disco.'s, Addco 1" rear sway-bar, 265/75/16 BFG MT's, and home-brew sliders, Spidertrax 1.25" wheelspacers to accomodate the new meats