We aimed to delineate the regeneration process of Japanese beech (Fagus japonica) by sprouting under strong and frequent human-induced disturbances, such as clear-cutting, weeding, and salvage cutting, and to assess the usefulness of the species as a natural regenerating tree in unsuccessful conifer plantations after clear-cutting of natural Japanese beech forests in Nikko, Tochigi. We investigated the stand structures and analyzed the growth of Japanese beeches and their spatially neighboring trees, focusing on 2 types of unsuccessful conifer plantations, (1) the Hinoki cypress plantations where weeding and several salvage cuttings had been conducted, and which were degraded by the bark stripping by bears; and (2) secondary broad-leaved forests resulting from the poor growth of conifers planted in locations where weeding had been conducted. Japanese beech exhibited stool structures with many stems resulting from sprouting under all the human-induced disturbances mentioned above. In the Hinoki cypress plantations, Japanese beech was the most dominant species under the tree layer of cypresses; in secondary broad-leaved forests early successional species, such as Betula grossa, were dominant in the tree layer, under which Japanese beech was dominant in the shade. Besides Japanese beech, almost no late successional species was observed under the tree layer in all the types of plantations. Therefore, Japanese beech could maintain a strong ability to produce sprouts and survive in unsuccessful conifer plantations under human-induced disturbances, and might become a main tree-layer component in the future. If unsuccessful conifer plantations are converted to broad-leaved forests, Japanese beech would be the most useful natural regenerator among the surviving broad-leaved trees.