Humans help spread the disease when they transport infected plants, plant parts or infested soil.
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.
Browning or dieback is usually caused by weather-related stress, sometimes in combination with pests and diseases.
Thinning is the term foresters apply to removal of some trees from a stand to give others more room (and resources) to grow. It is a tool for improving timber value, making sites more productive, and — perhaps most ...