Last year I was contacted by the owners of a property in Fremont, CA with numerous redwoods that had been in decline for several years. Previous to my involvement, various conventional tree service companies and experts had tried helping the trees, but to no avail. Their recommendation was to remove the sick redwoods. Fortunately, the owners were reluctant to cut down the redwood trees and decided to ask for my help.
Upon my inspection of the redwoods I found evidence of soil acidification and nutrient depletion. The owners followed my recommendations for fire mimicry treatments involving moss removal, soil mineral amendments, and compost tea.
Here are the results after just one year. Most, although not all, of the sick redwood trees are showing noticeable improvement in canopy density. None of the redwoods appear to be exhibiting further decline. Note that in photo set 20120912.2 below, the redwood tree on the left was removed during the past year. It was the one redwood I felt could not be revived with treatments.