Currently, the emerald ash borer has been found in trees only in Washington County, where a quarantine prohibits moving ash (Fraxinus) or fringe tree (Chionanthus) wood in or out of the area.
The first Tree School Online session debuted with 300 registered participants. Since then, the live classes have rolled out with anywhere from 50 to 100 participants.
Excessive summer irrigation of oak and madrone trees may promote fungal diseases such as the oak root fungus (aka armillaria root disease) and crown rot.