Pilot Study of 3D Spatial Distribution of -Pinene Emitted by Norway Spruce (L.) Karst Recently Infested by Ips typographus (L. 1758) (Coleoptera: Scolytinae)

The Eurasian Spruce Bark Beetle (Ips typographus) (L. 1758) (Coleoptera: Scolytinae) poses a significant threat to Eurasia's Norway spruce (Picea abies) (L.) Karst, forests. Early detection of infested trees is crucial to control beetle outbreaks and allow salvage logging before the next generation emerges. Besides traditional methods, new approaches focus on monitoring volatile organic compounds, mainly monoterpenes, emitted by infested trees. Using analytical chemistry, we studied the distribution of these compounds, particularly alpha-pinene, around infested trees. In lab trials, we optimized alpha-pinene detection using dynamic absorption and solid-phase microextraction (SPME), analyzed by gas chromatography with flame ionization detection (GC-FID). We conducted forest trials, revealing varying alpha-pinene abundance due to changing conditions. However, consistent trends emerged: levels were highest near the infested tree stem and 1.3 m above ground in the first trial and at a 1 m distance from the infested stem in the second. We generated a three-dimensional cloud depicting the distribution of alpha-pinene around infested trees in their natural habitat. These findings open avenues for detecting bark beetles on a large scale by mapping elevated concentrations of volatile organic compounds emitted by infested trees, potentially leading to alternative pest management methods. Scanning methods, such as electronic sensors combined with remote sensing, hold promise for this application.