Applications of computed tomography (CT) scanning technology in forest research: A timely update and review

Abstract

Organic materials of woody plants are complex and show internal, structural, and morphological variations due to genetic and environmental influences. Variability can be observed in stems, branches, leaves, and roots. Nondestructive and noninvasive technologies have been proposed to assess this variability. Computed tomography (CT) scanning, originally designed for medical diagnostics, permits the measurement of wood properties in situ (e.g., wood density, moisture content, internal defects, annual growth) and crown traits that characterize branching pattern geometry and canopy space occupancy for small-sized trees. Since Wei et al.’s (2011, Can. J. For. Res. 41(11): 2120–2140, doi:10.1139/x11-111) review on the assessment of wood quality for optimized manufacturing processes using a CT scanner, several important developments have occurred, motivating the preparation of an update. We provide technical clarifications about the scales of observation and resolution; report on recent studies in which CT scanning was applied with research objectives beyond wood quality assessment for an optimized manufacturing of forest products; and stress the importance of analytical procedures for the graphical and quantitative analyses of CT scanning data (images and numbers) and the need for specialized algorithms and software. With this review, readers are expected to be well informed of the avenues offered by CT scanning technology in forest research in general.