<p>Rapid deforestation and accelerating human pressures throughout the twentieth century reshaped forest landscapes worldwide, raising urgent questions about the role of heritage relics in ecological resilience. We compiled a national database of 363,282 heritage relic sites in China, including 307,666 heritage trees, 8,155 traditional villages, 5,060 cultural heritage sites and 42,401 religious sites, and integrated it with historical forest coverage data (1900–2020) and a high-resolution human footprint index (2020). Here, using geostatistical analysis and machine learning, we show that heritage relics function as long-term refugia, preserving forests during periods of deforestation and enhancing recovery during large-scale restoration. Heritage trees and traditional villages are associated with higher forest coverage and faster regeneration than religious or cultural heritage sites, especially in southern China and in regions of lower anthropogenic pressure. Yet these protective effects diminish as human footprints intensify, revealing the conditional resilience of relic-associated forests. Our findings demonstrate that biocultural heritage is not merely a repository of cultural values but also a dynamic ecological infrastructure that sustains biodiversity and ecosystem services over centuries. Integrating relic protection into conservation strategies offers an underused pathway for achieving global biodiversity and sustainability targets, including the Kunming–Montreal global biodiversity framework and the sustainable development goals.</p>