At a campfire: why does some wood snap n crackle? Is something happening in the wood?

Question

At a campfire: why does some wood snap n crackle? Is something happening in the wood?

Answer 1

My boyfriend takes credit for this one and he said it is the moisture in the wood that causes the noise.

Answer 2

The water trapped inside expands, turning into steam and bursting the wood open.

It's much like popcorn, but wood doesn't have the 'seal' that a kernel of popcorn does.  So, instead of constant popping, you hear alot of hissing and crackling.

Answer 3

Most of the crackle and pop comes from little _steam_ explosions, from moisture in the wood, But in "sappy" pines and other conifers, it can come from similar vaporization of other volatile compounds, like terpenes.