Timber species identification and selection principles of wooden components in the Sunjialou Cultural Relic Building, Nanyang City

To support the scientific restoration of Sunjialou Cultural Relic Building (Nanyang City), optical microscopy was employed to identify the timber species of key wooden components. The results are as follows: (1) Timbers belong to four families and five genera including Larix sect. Multiseriales, Pinus sect. Cembra, Cunninghamia lanceolata, Quercus sect. Cerris, and Ulmus sect. Madocarpus. (2) Timber selection exhibits dual characteristics of functional adaptation and regional resource dependence: High-strength hardwoods were utilized for core load-bearing components; decay-resistant softwoods for secondary ones; and easily workable softwoods for non-load-bearing/decorative components. Most timber species are local or near-source, aligning with the principle of local or near-source material utilization. (3) The findings systematically reveal the timber selection characteristics of Sunjialou architecture, confirming the traditional construction wisdom of function-oriented material selection. Simultaneously, this study provides a scientific basis for its restoration and serves as a representative case for related research in southwestern Henan Province.