Reply by GavinSA

Yo, Jeff,
The only reasons why I can see they say you shouldn’t would be for the following:
The internal workings are maybe not protected against high degree moisture which may lead to excessive rust or electrical short-circuit;
The idea of certain green woods maybe being too “stringy” might lead the cutter to jam up quickly causing additional internal wear or overheating
the green wood has not set so no matter if you plane it, it still hasn’t accepted its final resting shape. So if you plane it green, it might tend to twist as you open the pores of the wood which can lead to excessive fluid loss at different sections of the wood, which would inconsistency twist the wood?
I would believe the final answer would be that the wood wont keep the shape as it is planed green then when its planed dried.
Maybe you should just rough it for first, then at a later stage when drier, give it its final shape
Just an thought.

-- An unfinished project makes great firewood for winter!