The need for accurate and rapid field identification of wood to combat illegal logging around the world is outpacing the ability to train personnel to perform this task. Despite increased interest in non-anatomical (DNA, spectroscopic, chemical) methods for wood identification, anatomical characteristics are the least labile data that can be extracted from solidwood products, independent of wood processing (sawing, drying, microbial attack). Wood identification using anatomical characteristics is thus still a viable approach to the wood identification problem, and automating the process of identification is an attractive and plausible solution. The undisputed increase of computer power and image acquisition capabilities, along with the decrease of associated costs, suggests that it is time to move toward non-human based automated wood identification systems and methods. This article briefly reviews the foundations of image acquisition and processing in machine vision systems and overviews how machine vision can be applied to wood identification.
Xylem anatomy is fundamental in studies of the evolution of terrestrial plants, tree ecophysiology, forestry, and wood science. Traditional xylem anatomical studies by light microscopy utilize wood sections. However, the procedures are laborious, and high-quality histological sections have been particularly challenging to achieve from recalcitrant wood species and dry wood material. Modern microscopy offers opportunities for speeding up the xylem anatomical preparations. In this regard, the merits of using a sanded surface for wood anatomical research have been largely overlooked. Sanding of wood surfaces is practiced in dendrochronology and wood identification studies exclusively for the investigation of macro features, such as tree rings, wood porosity, or parenchyma patterns. We conducted microscopic level investigations of sanded surfaces of difficult-to-section high-density woods such as Dalbergia and Quercus species by reflected white light and epifluorescence microscopy. Reflected white light or combinations of reflected light and fluorescence could clearly show xylem micro-features in sanded wood surfaces. The resolution of cell types after sanding with 1000-grit was similar to the resolution obtained by transmitted light microscopy in histological slides. The advantages of sanded wood surfaces compared to traditional wood sections can be summarized as cost- and time-effective sample preparation, large sample area, intact cell walls and tissue structure, preservation of chemical content and extractives, and even focus of the field of view. A simple procedure of wood sanding instead of microscopic slides can be used for xylem microscopy and automatic image analysis of xylem structure.
Diospyros L. (Ebenaceae) is an important source of ebony, a precious wood used for several economically important timber products. Species are overexploited in many regions, including Madagascar, for both the national and international trade, but little is known about their wood anatomy, despite its importance for forensic identification. Wood anatomy has a major role to play in ensuring the sustainable and equitable utilization of Diospyros species that are not threatened by extinction, and in law enforcement to protect threatened species from illegal logging. This study aims to identify, describe, and test the usefulness of anatomical features to support a taxonomic revision of the genus in Madagascar and to enrich databases for wood identification. Ninety-nine wood specimens were collected from the various bio-geographical regions of Madagascar, representing 15 endemic species (twelve previously described and three new) of large trees (reaching DBH ⩾ 20 cm and/or height ⩾ 20 m) were investigated. Standard methods for wood anatomical studies were used. Statistical analysis of the data using Factorial Analysis on Mixed Data was performed for 14 wood anatomical characters. Detailed descriptions and comparisons of the wood anatomy of the 15 species are provided, along with a wood identification key. Analyses showed that all the characters are highly significant () in the separation of the species studies.