The coastal regions of Oregon and Washington have different climate and soils than other parts of the states. Rainfall is high, ranging from 70 inches in southern Oregon to more than 100 inches in the coastal mountains. ...
Soil, site, irrigation, selection, pruning/thinning, and integrated pest management.
Most “sick tree” problems can be traced back to underlying stresses that have reduced the tree's vigor, making it more vulnerable to diseases or insect pests.
A guide for how to collect and where to get a sample analyzed for plant diseases.