Study on Biodegradation of Wooden Components in the Sunjialou Cultural Relic Building in Nanyang City Using an Integration of Polarized and Fluorescence Microscopy and FTIR Spectroscopy

To evaluate the biodegradation status of wooden components in the Sunjialou cultural relic building in Nanyang City and provide a scientific basis for conservation, this study employed an integration of polarized and fluorescence microscopy, as well as FTIR spectroscopy, to characterize biodegradation in major timber species. The results show that the timber species are divided into two degradation categories: larch, Chinese fir, and elm were classified as severely degraded, with complete destruction of crystalline cellulose regions and total cleavage of lignin aromatic rings, while red pine and oak were moderately-severely degraded, retaining partial crystalline structure of cellulose but with complete lignin degradation. The biodegradation of wooden components results from the synergy between intrinsic wood properties and external environmental factors. Based on these findings, targeted classified conservation strategies and built environment optimization measures are proposed. This work provides scientific support for the preservation and restoration of the wooden components of Sunjialou.