You sir, are nuts, for not throwing some more loot in his direction to try to ensure staying power.
Maybe you should reread your post...
Lets see, the way I read it:excellent driver (CRITICAL SKILL), excellent on ropes (CRITICAL SKILL), "all he wants to do is work" (UM, YEAH, CRITICAL CRITICAL SKILL), loves to destroy large pile of brush (YES, CRITICAL), honest as the day is long (CRITICAL, YOU CAN'T TEACH THAT. MATTER OF FACT, YOU CANT TEACH ANY OF THE STUFF MENTIONED).
Buy, ya know, you're right about the guy. I have a good idea: You replace him with somebody with, ahem, leadership qualities, and just give him the plane ticket to CT that I'm sending you.