At www.sfgate.com/science/article/Ancient-redwoods-in-growth-spurt-of-a-lif… … very often we hear negative stories about the Californian giant redwood tree – they are on the verge of dying, global warming will suffocate them, and that kind of doomsaying. These trees are important as unlike European oaks that live for hundreds of years they can live for thousands of years. One tree near Crescent City is 2520 years of age and there is a giant sequoia that has survived for over 3000 years. Hence, tree rings from these trees could be used as a reliable climate proxy – for California. The tree rings could also, perhaps, mark out atmospheric down turns. European oaks are used by dendrochronologists, mostly from a collection of dead trees (involving cross matching of tree rings) so why aren't giant redwoods and giant sequoia used? Is it because of the micro climate, the mist and fog along the northern California coastal region, the influence of the ocean and moisture on growth? In the latest story we learn that redwoods have been growing more rapidly in recent years and the bumph factor is that it is blamed on increasing warmth. Actually, there is probably something in that and the authors do not necessarily imply co2 has caused the warmth (although that might be an obligatory add-on for publication), only that decreased levels of mist and fog have allowed increased sunlight, and warmth, to filter through the atmosphere.
The tree ring for the year 1739 was especially narrow indicating some kind of event along the coastline – but volcanoes in that year are not suspected. One to check out. See also www.rcci.savetheredwoods.org