Enhancing Wood Sample Preparation for SEM Imaging: A Detailed Study of Epoxy Resin Impregnation, Cutting, Sanding, and Polishing for Fragile and Heterogeneous Samples

Accurate characterization of wood microstructure requires high-quality sample preparation, especially for degraded, mineralized, or embedded samples. Through a detailed and systematic investigation, we suggest a simple, fast, and cost-effective method for preparing transverse surfaces of wood for scanning electron microscopy. The methodology used is easily accessible and simple. We compare traditional microtome cutting using both disposable blades and a fixed knife with sanding and polishing techniques. The choice of method is determined by the physical condition and structural characteristics of the sample. Disposable blades, when used with continuous moistening, yielded the best results for reference wood, while the fixed knife proved to be more effective for mineralized or epoxy-embedded samples due to their rigidity and resistance to deflection. Maintaining blade sharpness and surface moisture were critical in all cutting techniques. Polishing proved to be a particularly effective technique for the preparation of degraded, mineral-rich, or heterogeneous samples. In combination with epoxy embedding, it offers a practical alternative to microtome cutting, ensuring the protection of fragile structures, the long-term stability of samples, and the possibility of re-polishing. Epoxy impregnation was easy for degraded wood, while sprucewood required vacuum-pressure treatment. Care must be taken when polishing to avoid reaching non-embedded regions beneath the surface.