date: Thu May 12 12:10:12 2005 from: Tom Melvin subject: Re: Program to: Kurt Nicolussi Kurt, Thanks Tom At 12:03 12/05/2005, you wrote: Dear Tom, I need to separate modern / sub-fossil trees to test RCS curves. Have you got a list or separate raw data files for each (with pith) as I should use the same trees as you use. You should have got three different files - historical samples, subfossil material, living trees - with the pith-offset information. If you still have these files you can produce different RCS curves. The RCS curve for the Youngest trees (ALPS -63) goes up instead of down! The climate signal is sufficient to change the slope of the RCS curve when all trees come from roughly the same period. Your separation of modern trees for an RCS curve will require the use of Signal Free methods to remove this distortion. I should be able to demonstrate this on your trees when I have a separate "modern" RCS curve. There are only few trees with an age between 40 und 63 years - that can also be by chance. And in reality the "modern trees" (=living trees) are from the last 400 years, many of them started growth during the Little Ice Age. So, the "modern RCS" curve obtained are from a wide climate range. For me the effects of coring position and the effects of systematic sample bias - the trees with long series are slow growing trees - are bigger One possibility is to use many RCS curves to standardise producing series of tree indices with means roughly 1.0 and then to use the relative magnitudes of the RCS curves (to each other) to "reinstate" overall growth rate of each individual tree before averaging to get a chronology. I will try this on your trees as well. Sounds interesting. Kurt