Andrew R Stewart 

One design/fabricating challenge with a fork is that it's the only structural member (of a frame) that is connected to another member at only one end. All other members (tubes) are joined at both ends. This might seem trivial but to attain the strength and stiffness needed the dimensions and joining methods of wood are critical. Fork failure is not a nice thing to experience (seen too many results involving serious body damage...)

A metal steerer and crown unit will likely be employed as headsets only come in so many sizes. The crown will need to space the wood blades the right distance apart and allow for enough overlap for a good joint. So too with the drop outs need to overlap in the blades a lot. In the end there will likely only be a few inches of only wood between all that metal. Not sure beyond the ability to say one did make a wood fork what would be gained, and there's a lot to loose. Andy