Proceedings e report - Firenze University Press

NON DESTRUCTIVE IMAGING FOR WOOD IDENTIFICATION
Junji Sugiyama*, Suyako Mizuno, Yoshiki Horikawa, Chiori Ito, Misao Yokoyama
Laboratory of Biomass Morphogenesis and Information, Institute for Sustainable Humanosphere, Kyoto
University, Gokasho, Uji 611-0011, Japan
Abstract
Wood identification of Sesin-bosatsu-rituzou, registered national treasure, curved by UNKEI in Kamakura
period, has been performed by means of micro-CT imaging at SPring-8, Japan. The small fragment less than
1mm was investigated and 3-D information at 0.7 µm special resolution was obtained. Although the samples was
compressed in tangential direction and partly deteriorated, we could identify as Katsura, Cercidiphyllum
japonicum
1. Introduction
Wood identification based of anatomical features requires the observation of microstructure from 3
directions, axial, radial, and tangential. A way to do is to use a razor blade for making a thin slice from
wood blocks, and prepare the microscopy preparation of corresponding 3 directions. Nevertheless this
method becomes simple after training and experience, it is not applicable for example when only too
small sample is given as is always the case for national heritage class wood works or artifacts.
Therefore, we investigated the use of the synchrotron radiation facility(1) to shed a light on the
anatomy of national and world heritage wooden objects. X-ray micro-CT imaging at BL20XU was
carried out on specimens including cultural assets with a resolution of 0.7 micrometer. Sample twig
was trimmed less than 1 mm diameter (long along longitudinal axis), and 11 softwood species has
been carefully investigated with a series of programs developed by BL20XU, such as SLICE(2). The
resolution is good enough to visualize most of the species-specific anatomical features necessary for
the identification
2. Material and methods
The wooden statue Sesin-bosatsu-rituzou, registered national treasure, curved by UNKEI in Kamakura
period. was investigated. The sample was collected during its repair, a small piece the detached small
fragments with a dimension of 0.4 mm (R), 0.2 mm (T) 1.5 mm (L) as shown in Fig1. The sample was
so brittle to be sectioned without embedding. Furthermore, the sample was compressed in tangential
direction so that the surface was not clear enough to be explored by a scanning electron microscope.
As such, the sample was most suitable for X-ray CT imaging to be tested. X-ray micro-CT imaging
was done at BL20XU, SPring-8, Harima, Japan(1) and the data were analysed by a series of software
developed by BL20XU, such as SLICE(2)
* email: sugiyama@rish.kyoto-u.ac.jp
Fig 1 Seshin Bosatsu Ritsuzo, foot parts (R and L) and samples corrected.
Joseph Gril (edited by), Wood Science for Conservation of Cultural Heritage –Braga 2008: Proceedings of the International
Conference held by COST Action IE0601 (Braga - Portugal, 5-7 November 2008, ISBN 978-88-6453-157-1 (print)
ISBN 978-88-6453-165-6 (online) © 2010 Firenze University Press