Evolving Conservation Trends for Earthen Heritage: A Systematic Review of Terra Conference Proceedings (1972–2022)

Earthen heritage constitutes a significant yet vulnerable component of the world’s cultural legacy, encompassing archeological sites, historic monuments, vernacular buildings, and living cultural landscapes. Over the past five decades, approaches to its conservation have evolved in response to changing heritage paradigms. Since their inception in 1972, the international Terra events have played a pivotal role in shaping this field by providing a recurring platform for international exchange, knowledge production, and methodological development. This study aims to examine the shifts in research and practice through the lens of the Terra gatherings. Using a systematic review methodology conducted in accordance with the PRISMA 2020 guidelines, 638 papers from thirteen Terra proceedings (1972–2022) were analyzed and classified by geographic focus, disciplinary background, knowledge area, heritage type, construction techniques, deterioration factors, and intervention methods. The findings reveal a clear transition from early material and monument-centered approaches toward more holistic, interdisciplinary, and people-centered frameworks, with increasing attention to vernacular heritage, cultural landscapes, heritage management, and capacity building. The analysis also identifies persistent regional imbalances, a strong link between conference location and geographic representation, and a growing focus in recent decades on sustainability, disaster risk reduction, and climate change. Overall, the study demonstrates how trends reflected within the Terra proceedings have evolved and contributed to the discourse in earthen heritage conservation.