Resliced X-ray µCT scans of 17 tropical wood species – multiresolution experiment

When considering X-ray µCT for identification of a wooden sample, the question remains which resolution will be sufficient to visualize the wood anatomical features. This dataset contains the X-ray µCT scans, resliced along the three wood directions (transverse, radial and tangential), of 17 different wood species at four different resolutions. These scans form the foundation of a comparative study to evaluate the success of wood anatomical description resolutions ranging from 1 to 15 µm. The dataset of 17 scanned species is made available online to serve as a first step towards a reference database of scanned wood species, facilitating and encouraging more systematic use of X-ray µCT for the identification of wood species.

The 17 wood species studied in this paper were selected according to their occurrence among the objects of the Congolese heritage collection of the RMCA. In the past, 7% (3814 out of 55.000 objects) of the museum’s collection of wooden cultural objects was analysed and identified by the wood biology department of the RMCA. Based on this dataset of identifications (available here: 10.5281/zenodo.10671337), the most occurring wood species were selected:

RUBIACEAE Crossopteryx febrifuga Afzel. Ex G. Don EUPHORBIACEAE Ricinodendron heudelotii (Baill.) Pierre ex Heckel APOCYNACEAE Alstonia congensis Engl. BURSERACEAE Canarium schweinfurthii Engl. RUBIACEAE Nauclea pobeguinii (Pobeg.) Merr. VERBENACEAE Vitex madiensis Oliv. BORAGINACEAE Cordia millenii Baker MORACEAE Milicia excelsa (Welw.) C.C. Berg RUBIACEAE Nauclea latifolia Sm. BIGNONIACEAE Markhamia tomentosa (Benth.) K. Schum. Ex Engl. FABACEAE Albizia zygia (DC.) J.F. Macbr. FABACEAE Pterocarpus tinctorius Welw. FABACEAE Pterocarpus angolensis DC. APOCYNACEAE Funtumia Africana (Benth.) Stapf MORACEAE Ficus mucuso Welw. ex Fical VERBENACEAE Vitex ferruginea Schumach. & Thonn. OLACACEAE Strombosiopsis tetranda Engl.

Each sample was prepared for scanning by subdividing it into small cubes, tuned to the scan resolution: cubes of 1x1x10 mm for the 1µm scans; cubes of 5x5x5 mm were made for the 3µm resolution scans, and for the 8µm and 15µm scans the cubes were cut to 1x1x1 cm. The wood samples were scanned at 4 different ‘resolutions’ -more correctly the approximate voxel pitch of the scans but further referred to as resolution. The Nanowood X-ray µCT scanner was used to make the 68 scans (17 wood species at 4 resolutions). This scanner was custom-built at the UGent Centre for X-ray Tomography (www.ugct.ugent.be) and recently refurbished in collaboration with TESCAN-XRE (www.XRE.be, part of the TESCAN ORSAY HOLDINGS a.s.), a UGCT spin-off company.

The .jpeg files in this dataset are named as follows: Wood species_Tw number_resolution_wood plane_sequence number.

The Tw number references the 'Tervuren Wood' collection, or the Xylarium of the RMCA, which can be consulted via this website: https://www.africamuseum.be/nl/research/collections_libraries/biology/collections/xylarium

The resolution of the scans - more correctly the approximate voxel pitch of the scans - is indicated in µm 

The three wood planes are abbreviated in the file names: transverse (xs), radial (rls), tangential (tls)

The sequence number: for each scan, at least 3 reslices were made for each of the three wood planes. This to take full advantage of the three-dimensional nature of the scans.