USING COMPUTED TOMOGRAPHY SCANNING TECHNOLOGY TO EXTRACT VIRTUAL WOOD CORES, DERIVE WOOD DENSITY RADIAL PATTERNS, AND TEST HYPOTHESIS ABOUT DIRECTION, CORE SIZE, AND YEAR OF GROWTH
Computed tomography (CT) scanning technology was used to collect millions of three-dimensional data called “CT numbers”, on two sets of white spruce (Picea glauca [Moench] Voss) wood disks. Data collected were then converted to wood density estimates using a calibration equation for wood. Virtual wood cores with three different sizes (i.e., 1 voxel – the smallest volumetric unit on which a CT number was computed, 5 mm and 12 mm in diameter) were extracted from pith to bark and in four orthogonal directions. This made it possible to test the effects of core direction and size on the wood density estimates obtained. The average values as well as the radial patterns of wood density as estimated from CT scanning data were found to be typical of the values and patterns reported for the white spruce tree species in the literature, especially in relation to cambial age as the experimental trees were of different ages. In conclusion, wood science application of CT scanning technology allows extracting data subsets in 3D to perform density estimation, pattern analysis and hypothesis testing, and the results are valuable complements to those obtained with other technologies such as X-ray densitometry
