I wish I could find some info on the "elastic modulus" of wood.
I see the design problem with wood/glass (and even more so carbon/glass) being that you are expecting the wood to take the compressive load and the glass the tensile, which really can't happen efficiently. The glass skin will be buckled way before the wood is loaded up to failiure. However, In Reality, the wood supports the Glass laterally to prevent local buckling,(Like the rings Wouter wants to add?) and allows the glass to take compressive load. Can anyone come up with some numbers?
I suspect therefore that the glass/wood mast is not that much better than an epoxied wood mast. (In other words, the wood is probably typically able to handle enough tensile load to crush itself on the opposite side, and so you are essentially adding glass to do a job it is not particularly suited to, unless sandwiched or honeycombed to resist local"surface" buckling.
To return to the original question: Maybe it would shed some light to imagine the mast having failed by the glass skin first failing on buckling, and the fibres breaking, while none the less the wood kept the mast up. Going onto the opposite tack, the glass fibres parted in tension. The wood typically would not be asked to take this tensile load, because the glass skin is so good at it, and the design may not have intended it.