ITRAX

This technique, implemented using the ITRAX system, enables high-throughput analysis of wood density variations at 20 µm resolution (radiographic imaging at the intra-ring scale), combined with anatomical observation (optical imaging) and chemical microelement analysis at 50 µm resolution. The system can detect a wide range of elements, including Al, Si, P, S, Cl, K, Ca, Ti, V, Fe, Ni, Cu, Zn, As, Rb, and Sr. ITRAX is unique in providing joint analysis using these three complementary techniques (Fig. 1), although each method can also be performed separately if only one type of measurement is required.

Figure 1 : Example of ITRAX use, combining optical image, radiographic image, and chemical analysis of calcium content

Service scope

Our service includes sample preparation (cutting 2 mm-thick laths from cores or other samples), scanning, and data acquisition with the ITRAX, followed by:

• Interpretation of microdensitometry data using in-house software (CRAD, CERD, CESD) developed by the research unit (Mothe et al.)
• Interpretation of XRF spectra using the manufacturer’s software, including visualization, overlay for comparison, and semi-automated evaluation

The service can be provided partially (supervised equipment access) or fully (from acquisition to interpretation).

Microdensitometry results

In addition to the radiographic image, results include processed datasets with:

• Ring age and calendar year
• Mean, minimum, and maximum wood densities
• Earlywood and latewood densities and widths
• Simplified ring profile represented by vingtiles (each representing the mean density of a tangential band equal to 5 % of ring width)
   

Applications and research context

This system is currently used to study spatial variations in wood density (20 µm resolution) in relation to cellular structure, to explain:

• Seasonal patterns in conifer ring structure
• Effects of drought and other climatic variables
• Impact of functional biodiversity (e.g., mixed plantations) on wood formation and properties
   

These analyses have supported numerous collaborations and led to publications in New Phytologist, Forest Ecology and Management, and Annals of Forest Science (2014, 2015). They are linked to major societal issues such as:

• Monitoring environmental change
• Assessing carbon and nutrient budgets in forest ecosystems
• Evaluating industrial wood quality for new uses and processing methods

Contact :

• Equipment and unit coordinator: Julien Ruelle julien.ruelle@inrae.fr