Why 'wood' anyone think it 'wood' blow up or not work? The AR lower does not do anything except hold the mag, hold the upper in place, and hold the FCG. There is no real pressure put on the lower because if there were, those .50 BMG uppers would make short work of the aluminum lowers, and they don't. The only problem I see it being made out of wood is wear on the pivot pins, take down pins, and trigger pins. Once the pivot and take down pin starts to loosen up then the bolt carrier will get out of alignment with the buffer tube hole and that is going to cause malfunctions. Once the trigger pin holes start to wear that is going to cause ignition problems. But there is no danger of anything blowing up. It seems like a lot of work for a lower that would be heavier than an aluminum lower and nowhere near as long lived. The CF lowers and molded plastic lowers do fine so why wouldn't wood? I just don't see them lasting long.
The wood would almost have to be laminated or else as it swells, shrinks... I can problems with the mag not dropping free and the FCG binding, and shortest lived part of all, the thin pivot pin area will split or break and then that time consuming lower is just firewood.