Urban green spaces provide multiple services to humans, such as recreation, disaster-prevention, amenity and amelioration of the environment. They also function as habitat, conduits and sinks for wildlife in urban areas. A cost-effective and technically feasible way to exploit the multiple benefits of urban green space is to utilize existing green space rather than to create new ones. Shrine/temple forests, in which indigenous regional vegetation has been preserved in near-natural state, can potentially act as centers for preservation and management of urban green space. Research in shrine/temple forests began with the phytosociological description of the vegetation. In recent years, the realization that shrine/temple forests are a type of fragmented forest, has lead to research regarding community structure/dynamics, habitat functions, and physicalenvironment. Research has spread, both quantitatively and qualitatively, to the effects of social factors on forest structure/dynamics, such as management both within and around the forest, separation of Shinto and Buddhism and policy such as the Urban Parks Law. Research has elucidated the need to assess the functions of shrine/ temple forests from a large-scale perspective and to consider human and social factors in addition to ecological factors. In addition, we now have a scientific basis to argue that human management is essential in order to utilize shrine/temple forests as central urban green space. We must accumulate and integrate research at multiple scales using multiple methods for future conservation and management of not only shrine/temple forests, but urban green space in general.

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[in Japanese]

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The forests and precincts of shrines and temples play an important role as habitats for wildlife in urban areas. However, urban green spaces have been heavily developed and the ecosystem has been affected by various negative impacts. We discuss conservation of shrine forests and precincts as habitats for plants based on previous studies. The size of habitats is a main environmental factor that influences the number of plant species in shrine forests and precincts. Preventing the reduction of habitat size is essential to conserve plant species in urban areas. The fern species that prefer wet environments tend to be absent in small forests. It is necessary to preserve wet environments such as the lower slope of a valley wall and the bottom of a valley in order to conserve these species. Increased isolation diminishes populations of diploid fern species in shrine forests. The complex shape of forest habitats increases woody species that prefer edge environments. The distribution pattern of plant species in shrine forests and precincts in urban areas demonstrate nested subsets in area order. The combination of small green spaces is usually superior to one large green space in terms of number of species because the distribution pattern is not perfectly nested in reality. Most red-listed species in shrine forests are forest interior species that prefer stable environments and inhabit relatively large forests, whereas red-listed species in precincts were ruderal and segetal species that prefer human-settled environments. For conservation of red-listed species, it would seem desirable to conserve large sites for species in shrine forests and to conserve large and small sites for species in gardens.

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Various invasive species and escaped ornamentals have been reported to thrive in urban forest fragments. We found Trachycarpus fortunei Wendl. thriving in the shrine forest at Nishinomiya Shrine in southeastern Hyogo Prefecture. In this paper, we report on the complete removal of this species from the forest, the extent of the invasion, and the effect of the removal on the understory light environment. In addition, we assessed the cost of removal in relation to the amount of T. fortunei removed. T. fortunei density in the forest was 649 individuals per hectare, contributing 23% of the total number of trees taller than 1.3 m. Total basal area of T. fortunei was 1.7m² ha^-1, contributing only 3.4% of the total basal area, whereas in high-concentration areas leaf area index of T. fortunei was as high as 2.49-4.60. T. fortunei was especially concentrated in the northern edge of the forest facing a road and in the southwestern edge facing a parking lot. Reproductive individuals were also concentrated near the forest edge. In high-concentration areas, canopy openness in the understory was as low as 6-11%. After removal of T. fortunei, canopy openness increased by 2.2% on average (maximum 5.5%). The total cost of the removal of T. fortunei was 1, 390, 000 yen of which 72.0% was labor costs indicating that the cost of removal increases with the extent of the invasion. Shrine forests have traditionally been left unmanaged. However, this study showed that, active management is necessary to control invasive species if the objective is to sustain near-natural forest conditions. In fragmented urban forests, lack of management does not necessarily result in natural conditions. As such, human intervention may be needed to realize the management objectives of the land owner.

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