for the past several years, these trees have been suffering major blight- all the leaves turn black and die off, then the stems start to rot. We're about 1 1/2 years into a drought, and the trees, (we call em arbutus up here) are doing really well. The other nitrogen fixer which prefers the same locations, scotch broom- which is invasive- is not doing so well.
Similarly, there seem to be a healthy number of banana slugs out there, while the invasive black slugs are not as populous as previous years.
Red cedar and lodgepole pine in shallow soil areas are dying off like crazy.
Hard to know exactly what is going on, but something is definitely happening out there.