Anthropological significance of Tilia trees in Japan

Tilia (Malvaceae) is a genus of deciduous trees widespread in the northern hemisphere. Tilia species native to Japan include three endemic species, T. japonica, T. maximowicziana, and T. kiusiana, as well as the more widespread T. mandshurica. Other species were also introduced, the most important being T. miqueliana, brought to Japan with the arrival of Buddhism and planted on temple grounds as Bodaiju. Both historically and at present, Tilia trees are valuable to the people in Japan. Some Tilia trees are considered sacred in both Buddhism and Shinto. They are also prominent ornamental and park trees, albeit less popular in Japan than in Europe. Japanese Tilia spp. are used in the manufacturing of honey, cosmetics, lumber (especially plywood and veneers), and traditional bast cloth. Many Tilia trees are significant hubs in pollinator and mycorrhizal networks, but research on Japanese Tilia ecology is scarce. Despite their importance, Japanese Tilia trees have received less scientific attention in comparison with European Tilia species. The most striking example is T. kiusiana, with virtually no scientific literature regarding the species (save for a series of publications studying its secondary metabolites and potential medical uses). Furthermore, most published resources concerning Tilia in Japan are available only in Japanese, restricting their accessibility. This review seeks to translate, collect, and organize the information available on Japanese Tilia species. By doing so, areas are highlighted where new studies are necessary. A better understanding of these important trees would also be instrumental in their conservation.