As Peachey said, preserve is not a good choice. I think that 'save' isn't either, as that implies something like 'reserve' - something you don't want to use. I think that 'keep' is perhaps the word you want, if you are talking about somewhere to store it. Although - to be honest, I don't know that that is the case anyway. Most people just keep their wood in a basket, or in a pile beside the fire.

I agree with the second answer. I would use neither. Preserve is too formal, save in that sense is archaic (Save as in "rescue" is more popular) Keep or put would be much more common. I am assuming the container is being used to stop sparks flying out of the firevabd igniting the fuel that is meant for storage.

"Preserve" is a very awkward choice, as it suggests that the wood might deteriorate quickly. In this context, "save" means "put aside to use later".

If you can only choose from the two given then "save" is the better option for reasons already stated. Personally, I would like to use "store."