This is specifically a Minetest question, but I'd guess that Minecrafters could get in on it, too.
I've only just started playing Minetest, and haven't played Minecraft at all. In my very first world, I started in a large desert area. (Being my tutorial, I don't have a Mobs mod installed yet.) I did, eventually, see a wooded area on the horizon, but it got me to thinking. If you were to find yourself in a purely-desert world, how would you survive with no trees to make torches or tool handles with?