pin size black spots on trunk & limb
While I was pruning dead branches off the River Birch I noticed that most of the dead twigs and branches had very tiny, dot-like black markings. It doesn't come off with a rubbing. The spots are thick in number, separated by maybe 1/16 of an inch. The leaves on the limbs with these spots are few in number.
I found the same thing while pruning the Weeping Youpon.
Some of the Burfordi Holly & Nelly Stevens have the same kind of thing.
Can anyone say what this might be and hopefully someone will have a suggestion as to what I can do.