TANGLED UP IN BLUE. A methodological study of improvements in Blue Intensity and the impact of digitalization methods

Abstract

Blue intensity (BI) has proven to be an effective climate proxy within dendroclimatology, even if it does not quite match Maximum latewood density from X-ray measurements, for climate correlations on long time scales. This thesis examines different digitalization methods diving into differences between them and within methods with a focus on the blue intensity method. By digitalizing and analysing output data from different digitalization methods and parameters for BI, data was correlated to one another as well as temperature data. The thesis also includes data from other laboratories with differentiating digitalization methods for comparison. Our findings indicate that a higher resolution than what is commonly found in flatbed scanners can give a slight but certainly noticeable increase for temperature correlations for conifers trees in northern latitudes. Furthermore, there are strong indications towards resolution of the digitalization not being the sole factor for the temperature correlations variation. The parameter focusing on the cell wall did not see increased temperature correlations as parameters showed similar results.