Species, size, and location of "giant trees" in Tokyo's urban area and western suburbs.
The Japanese landscape has been characterised by the occurrence of ancient, massive trees described here as "giant trees", and many of these have had major historic, cultural, and religious significance. However, modern Japan has experienced significant and rapid urbanisation and in relation to ancient woods and trees, "cultural severance" too. This study identified the species, size, and locations of the giant trees growing in Tokyo's urban centre and its western suburbs, by conducting field surveys and collecting data from published studies. Classification of sites according to tree girth, with giant trees, revealed six broad locations: (1) forest and agricultural lands of managed secondary and later abandoned woodland with deciduous, broad-leaved trees; (2) public gardens, comprising useful and ornamental plants introduced from southern Japan; (3) parks, including mostly exotic species; (4) shrine sites, including Zelkova serrata, conifers, and evergreen broad-leaved trees; (5) temple sites, including many Torreya nucifera; and (6) Imperial lands, with rare species of trees in low numbers. The highest percentage of giant trees (36%) were found in parks, followed by temple and shrine sites (32%), whereas only 10% were found in other historical places. This study highlights the importance of studying giant tree habitats and history and identifying the relationships between human activities and living trees.