Balancing chronology and conservation: Near-Infrared spectroscopy for cellulose assessment in archaeological wood

Trees are fundamental to human survival and progress, serving as essential resources throughout history. From early societies to modern civilizations, they have provided materials for shelter, tools, transportation, and fuel. The development of ancient societies was often closely tied to forests, which supplied wood for construction, shipbuilding, and daily implements. Beyond their practical uses, trees hold profound symbolic and spiritual significance in many cultures, representing life, wisdom, and resilience. Moreover, their preserved remains continue to shape historical and environmental research, offering invaluable insights into ancient timelines, climatic shifts, and human activity. Tree rings serve as natural archives of past environmental conditions, while their organic material provides a crucial foundation for radiocarbon dating, one of the most reliable methods for establishing absolute chronologies in archaeology. By analyzing the carbon isotopes in ancient wood, scientists can precisely date artifacts, settlements, and cultural transitions, refining our understanding of human history and the broader prehistoric world. A major challenge, however, is that radiocarbon dating is a destructive method, requiring the removal and chemical pre-treatment of a portion of the wood sample necessary for the ¹⁴C age determination. This process permanently alters or consumes the analyzed material, posing a significant dilemma for archaeologists, especially when working with rare or culturally significant wooden artifacts. Therefore, sampling must be minimized as much as possible while still ensuring accurate ¹⁴C measurement. To address this issue, this study explores the potential of Near Infrared (NIR) spectroscopy as a non-invasive diagnostic tool for assessing cellulose preservation in archaeological wood specimens before radiocarbon dating.

The Near-Infrared (NIR) technique was applied to a set of well-characterized archaeological wood samples covering a wide range of chronological periods, provenances, and depositional environments. Short-Wave Infrared (SWIR) hyperspectral data were acquired from the specimens and analyzed through a combination of qualitative spectral interpretation and chemometric methods, including Principal Component Analysis (PCA) and single-band spectral mapping.

Overall, the results indicate that NIR spectroscopy represents a rapid, reliable, and completely non-destructive approach for assessing the suitability of archaeological wood for radiocarbon dating. By guiding targeted and minimally invasive sampling, this method improves the efficiency and robustness of ¹⁴C analyses while reducing unnecessary material loss. The proposed workflow contributes to more sustainable radiocarbon practices and aligns analytical requirements with the principles of cultural heritage preservation. Furthermore, the integration of hyperspectral imaging and chemometric analysis offers promising perspectives for broader applications in archaeological science and conservation, including the non-invasive characterization and monitoring of wooden cultural heritage objects.