Wood in Japanese can be: もくざい or mokuzai (More in talking about wood building material) It can also be: き or Ki (wood)
its kuro
kokuchou
kuroji
kuroari
kuroikokoro
Kurotsuki
Kokushibyou
Kuro Aisu=Black Ice
Kuroi sora is black sky.
kuroi no kumo
kuroi daiyamando