Common is spelled with an 'o' rather than an 'e' and breeded dwarven slaves is an awkward phrase.
I would suggest breaking up that long sentence into smaller ones to make them easier to handle.
"In this wooden city, the vile Arborelves rule over the common people in glory and light. Far beneath the surface, dwarves bred to be their slaves produce the evil shey'ling drug from the seeds of the subterranean shey fungitrees. Known as 'dreamdust,' the elves use this fiendish drug to bring friend and foe alike under the control of the merciless pleasures induced by this evil poison."
I dunno... something like that.
You could simplify or tweak it more. Others might have suggestions.
The only actual spelling mistake was the word common.
Ah... and you capitalized West Gate, but East gate has no capital on Gate.
I love the map though. Interesting to think of dwarves enslaved by elves. I see a revolt coming... and if the slaves control the drug... what nobles will be in the palm of their hands? Those who have dipped into that dreamdust a little to much...