He shaved his head because hair + sunscreen + superconcentrated bug spray + sweat - showers = gross. Also, why not? Start out the new adventure with a clean slate...erm...head.
Though as he says, "Turns out, shaving your head doesn't make you braver."
Here are some pictures from the great event, plus a shot of him and his hiking partner getting ready to leave, showing off his ~45 pound pack :-) Note: his partner's pack weighs over 60 pounds! This is the most weight they will ever have to carry (the first stretch is the longest), but still. Oof!