Redwood Tree Health
I planted a number of Sequoia sempervirens around my property on the western slope of the Sierras at about 3, 300 feet elevation. They seemed to do well for the first few years but have recently started turning brown, branches thinning, and a few have died. I attribute the deaths to pocket gophers, which are abundant here, but I wonder if I should treat the soil somehow.
Information states they thrive best at 3000 feet or below with heavy rainfall (100"/year) and high humidity. Have you contacted your local agricultural extension service or the Forrest service?