I would not substitute wood for some other resource.
If you would like to have wood in this DK game, go for it.
Tables, torches(every wall got one?), Tools like pickax handles,
wooden shields, what have you- a well for water
it does not have to be realistic just feeling like a thorough,
little believable world.
wood is too important and hard to substitute imo
Thoughts
1-send workers outside to gather wood/ raid villages
possibly attracting good- doers
2-Spell to teleport or create wood.
3-Races , like Goblins each bring their own amount of wood-
eg you summon a worker and it comes with 2 wood
4-Trade 1:2:3 with gold and coal respectively.. somehow improve that
ratio
5-wood is just there, do not bother where it comes from or how
6-what does DK do about it?
make your live as easy as possible without missing out on important stuff
if your creative fluids are flowing about a ressource wood,
you can think of many combinations about wood it is feeling good,
so why use bone?
(while bone and funghi are all cool)
http://en.m.wikipedia.org/wiki/Bonecruncher
also if you want to experiment go for it(oil etc)
cool game you got there, at first I thought that is exactly
DK, like ameena(point being?

) I see you want a better version
I find the red dots very important, yes maybe tune it down
The walls look good from afar but change appearance( more noise looking)
when zoomed in. Could you increase or decrease detail for zoom factors)
walls not feeling "as one"- but could be me