Knowledge Structure and Evolution of Global Ancient Tree Research: A Visual Exploration Based on CiteSpace

Ancient trees, as rare natural and cultural heritage, are a global research focus. Based on 462 publications from the Web of Science Core Collection (1998–2025), covering 68 countries/regions and 403 institutions, our analysis shows the following: (1) Publication output grew steadily, with increasing interdisciplinary integration around growth and conservation. (2) China leads with 120 publications (25.97% of the total), followed by the United States with 75 (16.24%); together they account for 42.21%. The Chinese Academy of Sciences is a key contributor, but international collaboration remains limited. (3) Keyword analysis highlights conservation, growth, biodiversity, diversity, and forest as core themes, with recent bursts in biodiversity (5.39), climate (3.85), and forest management (3.47). Future trends include holistic conservation frameworks, climate response, belowground ecology, longevity mechanisms, and big data, digital twins, and AI for precise, preventive management. This work matters because ancient trees are not just old plants—they are vital parts of our shared natural and cultural heritage that benefit ecosystems and communities worldwide.