The largest blade I'll pack for chopping is my 15 inch blade Condor Bolo, though it is more of an allaround tool than some of Condor's other blades, like the 13 inch Khukri-which is significantly liter and bites MUCH deeper. It also offers alot more control. I picked up a HI WWII Khukri this week and although it's a beautiful piece and an obvious performer, I think the Condor Khukri takes the cake as my favorite chopper only - that blade shape has a useable working point but good luck trying to efficiently baton or drawknife with it. Whatever you do, pick up a 14 inch Tramontina. The tin blade and thin flat grind (everybody loves to convex these but they're obviously an extremely deep biting V grind tipe of blade) takes no more than gravity to take inch and a half V notches out of dry wood. I have two more choppers in the works, a really wide, thin grind hudson bay and a HI Annapurna Bowie. I'll post more when I get hands on...
PS, my Condor Khukri's balance and overall weight is almost EXACTLY like the balance and weight of my HB Forge Shawnee hawk. Swinging that thing was second nature after using a hawk as my primary chopper for more than a year.
Local vegitation is anything from extensive pine scratch, to cottonwood, locust, sagebrush, and the occasional desert overgrowth in the saddles.