Fig. 1

Study sites. a Map of study sites. In each forest site, a number in a parenthesis indicates the number of plant species/taxa observed in the 240 terminal root samples from which sequencing data were successfully obtained. The map published by DesignEXchange Co., Ltd. was purchased by the corresponding author (H.T.), who has the right to edit and publish it. b Relationship between the number of samples and that of plant species/taxa observed. A rarefaction curve obtained from 240 terminal-root samples is shown for each study site