Materials and Construction Techniques of Unified Silla Wooden Architectural Members Excavated from Wolji, Korea

Comprehensive studies on the material characteristics, construction techniques, and decorative practices of architectural components excavated from Wolji, Gyeongju, remain limited despite the site's importance as a palace complex of the Unified Silla period. This study investigated architectural members excavated from Wolji through wood species identification, X-radiography, and XRF and XRD analyses. Wood species analysis showed that pine (Pinus spp.) was the predominant timber used in the structures. XRF and XRD analyses identified hematite (Fe₂O₃)-based red pigment on both eave and balustrade members, indicating that red coloration was applied throughout the buildings. X-radiography revealed that architectural members were assembled using timber joinery reinforced with iron nails, while metal analyses demonstrated a functional distinction between structural iron fasteners and decorative copper-alloy elements. These findings indicate that Unified Silla palace architecture employed integrated systems of timber selection, joinery, metal reinforcement, pigmentation, and metal ornamentation. The study provides archaeological evidence for reconstructing the construction technology and decorative practices of Unified Silla wooden architecture and contributes comparative data for understanding East Asian timber-building traditions during the seventh to ninth centuries.