Using lenses attached to a smartphone as a macroscopic early warning tool in the illegal timber trade, in particular for cites-listed species

Abstract

Wood anatomy is a key discipline as a tool for monitoring the global timber trade, particularly for wood listed in protected species conventions such as Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES). One of the main barriers to reducing illegal trafficking of protected species is ensuring that customs officials with appropriate training in wood anatomy are equipped with simple tools, at both the origin and destination of shipments, so they can raise an early warning about wood suspected of contravening international treaties and immediately send samples to a specialised laboratory. This work explains how lenses attached to a smartphone, capable of achieving up to 400× magnification using the phone digital zoom, can be used to distinguish features that are not visible with traditional 10× or 12× lenses, enhancing the capacity to view features not typically observable in the field. In softwoods, for example, this method permits determination of the type of axial parenchyma arrangement, whether there are helical thickenings in axial tracheids and whether axial tracheids have organic deposits or contain alternate polygonal pits, and in the rays, if the tracheids are smooth-walled or dentate and if the cross-field pits are window-like. In hardwoods, it allows verification of the presence of tyloses and deposits in vessels, the type of perforation plates and whether the intervascular pitting is scalariform; in the rays it is possible to differentiate the types of ray cells; and in the axial parenchyma, to determine the presence of oil cells. In addition, unlike macroscopic analysis with a conventional magnifying lens, this type of lens can be used with the appropriate mobile application for the biometry of important elements such as ray height and vessel diameter.