Application of imaging tools for investigation of penetration and distribution of protective agents in wood
(Topic A.2)

– In which anatomical structures do (novel) protective agents move? 3D computed tomography imaging will help to answer this –

For a long-term utilization of wood a deep and homogenous protective treatment (wood preservation, wood modification) is required. This is especially evident for non-durable wood, such as European beech and Norway spruce. However, these protective treatments do not ensure an absolute protection against wood decay, even at an early stage. This early-stage decay of treated wood is mainly caused by an uneven penetration of protection agents.
During the impregnation, the protective agents, however, do not always spread homogenous in the wood. Consequently, local areas with an incomplete protective effect occur throughout the wood. Wood-destroying fungi can easily infect such unprotected regions of the treated wood. Thus, a deep and homogenous penetration and distribution of protective agents into the wood are required for a long-term utilization. Up to now, however, the (anatomical) features that cause an improper impregnation of protective agents are not fully understood. This limited knowledge is particularly caused by the restrictions of the classical imaging methods (transmission light and scanning electron microscope) which are based on destructive imaging of the wood tissue.
In this study, the innovative X-ray based micro-computed tomography (nanotom® s, GE, Wunstorf, Germany) is used as primary investigation method. The purpose of this non-invasive technique is to obtain a genuine 3D imaging of the internal structure and composition of wood. The main objective of this study is to gain detailed knowledge of the still not well known distribution pattern of especially novel and more eco-friendly protective agents (e.g. micronized copper) by using this powerful technique.
Concerning the increased and unused resources of hardwoods, this study focuses mainly on the impregnation pattern of hardwoods (beech, ash, poplar). Beside hardwoods, this study examined also two softwoods species (Scots pine, Norway spruce).
The gained knowledge of the distribution of protective agents in hardwoods could contribute an adaptation of wood protection processes on hardwoods which are still dominated on softwoods. In addition, this adaptation could promote an increased and sustainable usage of native (non-durable) hardwood species in the practical application.