Cedar

My 30-40 ft cedar has a black and white line (approx half the truck wide) running up the tree. Can’t for the life of me find anything on the internet to tell me what this is?

 

Welcome @Blg. How about replying with some photos so that people can see exactly what kind of tree you are talking about and what this line looks like. See Attach photos and files.

 

You might want to check out lightning damage to your tree. Doesn't have to be a death knell.

 

I see now the entire truck is almost black with the white fungus or mild mixed in. The trunk was entirely the light shade which is now only 6-8 inches wide!

Any ideas?

 

This is exactly why Wendy wanted a picture. That looks to me as if you have had rain or very high humidity there. The darker areas will lighten as they dry. The lighter areas are just the usual bark in drier condition. No damage, no mold.

 

Thank you - we are in the rain forest and I thought it odd none of the other cedars or firs did this. Having said that it’s growing on a huge rock and until lately has had no water for months.

Thanks again I can now rest easy that it won’t topple over!

 

Your tree is a Western Redcedar (Thuja plicata), not a Cedar (Cedrus) at all. Agree the trunk is just wet.