%0 Journal Article %T Review of Plant Species Diversity in Managed Forests in Japan %A Takuo Nagaike %J ISRN Forestry %D 2012 %R 10.5402/2012/629523 %X The effects of conifer plantation management and forest fragmentation on plant species diversity in Japan were reviewed. While most studies have demonstrated that the practice of thinning in coniferous plantations can enhance species diversity of naturally regenerated trees, such as broad-leaved trees, some have shown that thinning reduces plant species diversity through the direct physical disturbance to forests. In addition, plant species diversity in plantations has also been shown to be dependent on the distance from seed sources. Extensive forest fragmentation due to land use changes has occurred, particularly in forests near urban and suburban areas. Although the number of species per unit area in abandoned coppice forests is not clearly related to the extent of forest fragmentation, most species attributes (such as rare species) are negatively influenced by forest fragmentation. Some of the forests owned by shrines and temples in urban areas are similar to island forests and are relatively well protected from human disturbance. To more clearly understand and evaluate changes in biodiversity through forest management, elucidating the interactions between management and plant species diversity, species composition, and the ecological traits of various species is therefore necessary. 1. Introduction Forest management typically has a marked affect on plant species diversity, which is an important ecological indicator (e.g., [1]). Understanding the effects of forest management practices on plant species diversity is important for achieving ecologically sustainable forest management [2]. Most of the forests that cover Japan¡¯s surface are managed; these include plantations, coppices, and selection or selectively cut forests [3]. The plant species diversity of these managed forests is thus important for maintaining, conserving, and restoring biodiversity in Japan. Globally, forest management policy has changed in response to changes in public awareness of the multiple functions of forests [4]. In Japan, studies of plant species diversity in the managed forests of the country have increased markedly since 2000 [5, 6]. Species diversity is an important index in community ecology (e.g., [7]). Although species richness and diversity are useful indicators of the effects of forest management practices, species diversity per se is also important in biodiversity. For example, forest stands with relatively higher species richness or diversity are not always much better for biodiversity, as undesirable species (e.g., invasive or exotic species), which frequently %U http://www.hindawi.com/journals/isrn.forestry/2012/629523/