Rising Termite and Fungal Decay Hazard for Korea’s Wooden Architectural Heritage, 1973 to 2025: A Climate-Based Framework for Biodeterioration Risk Assessment

Abstract

Wood-decay fungi and subterranean termites shorten the service life of timber, and both become more active as temperatures rise. This study presents a climate-based framework for assessing the biodeterioration hazard of wooden heritage and applies it to all 506 state-designated wooden heritage buildings in the Republic of Korea from 1973 to 2025. Daily temperature and precipitation at each building were estimated from a bias-corrected one-kilometer climatology (cross-validated root-mean-square error 0.66 °C). Year-to-year variation was taken from anomalies at 61 long-term stations. Five annual indicators were derived: mean annual and January temperature, termite activity days, a climatic termite hazard index, and the Scheffer climate index for fungal decay. Between the first and the last decade of the record, mean annual temperature rose by 1.49 °C and January temperature by 1.65 °C; termite activity days increased by 7%, the termite hazard index by 27%, and the Scheffer index by 12%. The termite index rose more than the Scheffer index at 459 of 506 sites; these are relative changes in climate-based indices for different exposures, not measured deterioration rates. The framework supplies the hazard component of a heritage risk assessment and a baseline for projecting hazard under climate change and planning preventive conservation.