Dwarf Fortress's main idea isn't about Geology at all
Dwarf Fortress may not set out to be a geology simulator, but that doesn't change the fact that it is (perhaps incidentally) a geology simulator.
There is a world of difference between the Settlers' brand of "iron + coal => sword", and Dwarf Fortress' complex mineral trees.
Iron + Coal doesn't equal a sword anyway. Also, as for Dwarf Fortress, I'm just saying that if he wasn't a realistic game, he can have them trees in if he wants to.
Coal -> Fire
Coal used to make Fire. Fire used to heat Iron. Hammer used to hit the heated Iron. Repeatedly. Iron becomes Blade. Blade combines with Hilt. Results in a Metallic Pointy Stick of Sharpness.
Coal -> Fire
Coal used to make Fire. Fire used to heat Iron. Hammer used to hit the heated Iron. Repeatedly. Iron becomes Blade. Blade combines with Hilt. Results in a Metallic Pointy Stick of Sharpness.
Depending on time of course. Back in Sword times, if I am correct, they used wood more than they used coal. Wood was used frequently in medieval times, instead of Coal, because it was easier to get.
Depending on time of course. Back in Sword times, if I am correct, they used wood more than they used coal. Wood was used frequently in medieval times, instead of Coal, because it was easier to get.
I don't know what " sword times" is, specifically. 
The sword was used for a very long time.
Here's a pretty good run down of smelting techniques used during "sword times". <3 For a game I'd never heard of before. http://www.modernparapsychology.com/Gamer/Moloch/Smelt.html
And, as ever, Wikipedia is a fair springboard for historic research. http://en.wikipedia.org/wiki/Mining_and_metallurgy_in_medieval_Europe
ADDENDUM: I rather enjoy this topic; it's gotten me to read into how smelting works (both now and then) which is something I knew very little about previously. Very interesting stuff.
Sword Times = Medieval Times. That's when they were very popular. But your right, they were used for many years. Norman's, and all that (I'm English, so I base it off English historical periods).
Sword Times = Medieval Times. That's when they were very popular.
Medieval is a specific time period in a specific geographical location. Europe (and to some extent, parts of the Middle East and some parts of Asia) in a Pre-industrial Revolution (<1700 AD), and post-Roman Empire (>350 AD) time period.
Swords have been in use for the majority of human history, in many geographical areas, and were "very popular".
But now I'm just nitpicking. And offtopic. 
I think you're right about the wood burning, though. An interesting addition to the link @thade posted: Wootz Steel.
