Effect of Shredded Scots Pine Cones (Pinus sylvestris) on the Mechanical Performance of Three-Layer Particleboards

This study investigates the use of shredded Pinus sylvestris (Scots pine) cones as a partial replacement for industrial wood chips in the surface layers of three-layer particleboards. Boards were produced at a density of 700 kg/m³ and thickness of 16 mm using urea-formaldehyde resin, with cone particles replacing 10–60% of wood chips in the outer layers. Mechanical tests showed that all boards met EN 312 flexural strength requirements, with up to 15% improvement in surface screw pull-out resistance at the highest cone content. SEM analysis revealed that pine cone particles have a complex, entangled fibrous structure, unlike conventional chips, enhancing mechanical interlocking with the resin. This improved interfacial bonding contributes to better stress transfer and reduced porosity in the outer layers. Additionally, boards gained unique aesthetic features from the natural coloration of cones. The results support the use of underutilized biomass for sustainable, structurally sound, and visually appealing wood-based panels.