Yeah I was gonna say Eucalyptus clown beetles, but the absolute evenness puts me off and your in USA, so I don't think you even have them?http://www.brisbaneinsects.com/brisbane_bugs/DarkClown.htm
I get damage a bit like that on mine here, mostly on old growth, when the eucalyptus drop their bark and the bugs migrate.
So my next best guess was wind damage but again its so even and minor?
If it were mine, I would give it a hit with Huacatay/Blackmint/Tagetes minuta spray or Pyrethrum, nothing oily though.
Shovel on a little ash compost and manure, give it a big water and cross my fingers.
Hang on a minute, its not just minor burning from months ago (that's just taken a while to show up), from a growth hormone spray or some other magical potion along those lines is it?