What happens to wood under pressure?

I know it sounds like an innuendo - just please, don t.

So, in a story I ve been writing one of the characters has superhuman strength. In one scene (a series of events too difficult to summarize in a yahoo answers question) they are so upset that they squeeze the sides on their wooden bed.

What would happen to wood being squeezed under superhuman pressure? Would the wood split, splinter, or just get impacted? Does the type and thickness of the wood matter? Would humidity be a factor (like it would be more likely to split/splinter in a drier atmospheric setting)?

It s a small detail but I like to get these things right when writing (and learning is cool).