Madrone can live a long time, as they have a large woody tuber that can resprout after cutting or fire. However, there are some foliage diseases and branch cankers that seem to really knock them back in some years. Madrone loves full sunlight, and if shaded can look pretty bad, and we think sometimes the foliage disease might be worse. The bottom line: the foliage diseases seem to be the most significant factor in the region, and many folks have trees that seem sickly, but continue to live. We do not have a cure really, and it seems to be especially related to weather; warmer winters and wet/warm springs.
here is an OSU Extension pub on Madrone issues:
Also, a website from Washington State Univ, where the folks near Tacoma have been doing lots of research on Madrone problems:
Hope this helps