The Preta Path works by the user rotating their chakra in the opposite direction of an incoming chakra-based attack, allowing the user to disperse the chakra of the attack throughout their body, nullifying the attack.
That's the gist of what the Naruto Wiki says. So, based on that information, I assume this:
Preta Path can absorb the chakra from the Wood Release (effectively taking it's life), but cannot absorb the physical wood; so, the wood would still be there, but it would contain no traces of chakra. That is my opinion from what I can gather.
Just my thoughts. =]