Back To The Future With Tree-Ring Standardization: Maybe Schulman Did It The Right Way

This talk reflects over 45 years of research and contemplation by me on the tree-ring standardization problem. There is no optimal solution to this problem because the statistical properties of the raw ring-width data we typically process are very complicated and their expressions of radial growth over time are totally unobserved. It has recently become apparent to me that we spend too much time letting the computer do the standardization for us without taking time to look at the data. This realization has taken me back to the days of Edmund Schulman when tree-ring series were standardized graphically and by hand. It is not possible to relive those days in any practical sense, but revisiting the way Schulman detrended his data as described in his landmark Dendroclimatic Changes in Semiarid America monograph provides an interesting perspective nonetheless. No solutions will be provided in this talk because none actually exist. Only some insights and suggestions on how we might avoid making some mistakes and how we should spend a bit more time looking at our data in a computer-assisted way.