X-ray imaging and computed tomography of conifer tree rings for climatological purposes

This paper presents images of wood structure for various measurement regimes of X-ray microtomography. This is done by obtaining tomographic slices (iSee, CTvox), averaging them with the help of a statistical script called Adobe Photoshop, converting the average images into multidimensional data sets, and then averaging the image profiles (OriginCalc) to finally obtain a two-dimensional array of dendrochronological series of tree-ring density. The results of measurements are checked by a weight method to confirm the reliability of the data processing algorithm. For dendrochronological measurements of the ring density, it is shown that, depending on the width, two modes can be used: 80-µm (for wide rings) and 30-µm (for narrow rings). A measurement mode of less than 10-µm is used to display the structure of the wood inside a ring. The results of XCT-density measurements performed with an 8-µm resolution are given to assess the daily changes in wood density during the growing season.