Black Stuff on Giant Sequioa

[rhawes]

There appears the needles on my giant sequioa have a little black on them and it it moving up my tree. I currently have it in a greenhouse outside. Anybody have any ideas why or what could be causing this. Is this fungal or something else I really do not want to lose my giant sequioa.

 

[Wires_Guy_wires]

Google for Sooty Mold. If it's that, look for aphids.
Otherwise it's possibly some other sort of mold related to bathroom molds that can occur when there's a lack of air movement.
A good picture would sure help!