This is supposed to be the work of the invasive Polyphagous Shot Hole Borers. The hole borers are small beetles that bore holes into the trees and then plant fungus in the holes for their grubs to feed on. The fungus may continue growing until it weakens and kills the trees. The beetle is an invasive species that has broken out in multiple locations in Orange County, and decimating trees at each.
Huntington Beach Cenral ParkTree fallWoodland