Core business: X-ray CT toolchain for tree-ring analysis

Disentangling tree growth requires more than ring width only. Although X-ray densitometry is an established technique to determine key wood density parameters, tedious manual procedures hamper fast analyses. De Mil et al. present an X-ray computed tomography toolchain to enable high-throughput density profiling of large sets of increment cores.

3-D rendering of the sample holder volume containing the tree cores
(A) 3-D rendering of the sample holder volume containing the tree cores. (B) Cross-section of the volume with indication of the cores (green dotted circles) for batch extraction. Reference material (yellow circles) and air (blue circles) are extracted and used to convert the separate core greyscale values into wood density values. (C) Tilt and tangential alignment of the core volume for further analyses. Scale bar = 5 mm. Image from De Mil et al. 2016.

The obtained 3D archive is analysed via software routines with which traditional tree-ring analysis, as well as semi-automated density-based pattern matching, can be performed. The toolchain allows fast assessment of newly sampled increment cores, without any surface treatment or visual inspection. This offers the opportunity for large-scale screening of lesser-studied tree species, and improving current chronologies with sub-annual density information.

Reference List

Tom De Mil, Astrid Vannoppen, Hans Beeckman, Joris Van Acker, Jan Van den Bulcke, 2016, 'A field-to-desktop toolchain for X-ray CT densitometry enables tree ring analysis', Annals of Botany, vol. 117, no. 7, pp. 1187-1196 http://dx.doi.org/10.1093/aob/mcw063