It looks as if someone took a spray bottle of something toxic and randomly sprayed parts of our cedar trees. We do have an unfriendly neighbour behind us with barking dogs... she doesn't like me telling her dogs to quiet down when they're barking in my face... anyways, our trees (on her side only) have patches of browning areas. I asked her hubby (who's friendly) if he had possibly sprayed or fertilized and maybe the wind blew some onto my trees... but he said no he doesn't spray because of his dogs. It's only on the one sunny side of the trees, and only on parts of them, the trees are VERY healthy and have grown huge this summer, they're big and fat and dark green and at least 4' tall now, so definitely healthy. They were under 1' when they were planted 3 years ago. There's no sign of bugs or rotting anywhere. Any clues? My only guess is that the sun hits the heavy morning dew and is burning them a bit?