I just downloaded a mod that allows arrow crafting from firewood. But I only found firewood by cutting logs, and that's way too boring and slow.

So, is there any other quick source of firewood? Maybe buying directly from a merchant?

Not that I have found, sorry.

Wait until somebody picks some up, then shoot them. Use the firewood they picked up to make more arrows, and then shoot the next person to pick some firewood up, to make more arrows to shoot the next person to pick firewood up.

Wait a second...

Since Firewood is an item that can't be used, I doubt merchants would sell it.

Some merchants sell it.