Ecological restoration of a fragmented urban shrine forest in southeastern Hyogo Prefecture, Japan: Initial effects of the removal of invasive Trachycarpus fortunei

We investigated the species composition of a fragmented forest in Nishinomiya Shrine, southeastern Hyogo Prefecture, Japan. Two escaped ornamental species, Trachycarpus fortunei and Ligustrum lucidum, and bird-dispersed deciduous trees were invading the evergreen broadleaf forest. Invasive and bird-dispersed deciduous species were most abundant along the outer edge of the forest. In 2005, restoration measures were taken to remove all individuals of T. fortunei from the forest. We estimated that, biomass density and leaf area index (LAI, leaf area per unit ground area) of T. fortunei were 0.23 kg m⁻² and 0.77, respectively, which accounted for 8.9% and 27.9% of the biomass density and LAI, respectively, of the entire forest. After removal, canopy openness increased in the understory. However, the understory lacked seedlings and saplings of native species, indicating that active re-vegetation may be needed to accelerate reestablishment of native species in areas that were heavily invaded by T. fortunei. This study represents one of the first examples of active vegetation management in shrine/temple forests in Japan.