I am sure they thought about it. I mean, that’s the first thing that comes to mind and I never really studied wood. So I am not going to assume that they ignore

I am sure they thought about it. I mean, that’s the first thing that comes to mind and I never really studied wood. So I am not going to assume that they ignored the obvious. That said, wood can be treated to remove quite a lot of stuff, leaving behind a strong porous structure that can be filled with various things to tweak its properties.