x-ray computed tomography is a widely used method for nondestructive visualization of the interior of different samples - also of wooden material. Different to usual applications very high resolution is needed to use such CT images in dendrochronology and to evaluate wood species. In dendrochronology big samples (up to 50 cm) are necessary to scan. The needed resolution is - depending on the species - about 20μm. In wood identification usually very small samples have to be scanned, but wood anatomical characters of less than 1 μm in width have to be visualized. This paper deals with four examples of x-ray CT scanned images to be used for dendrochronology and wood identification.