Species dynamics and colonization patterns in an abandoned forest in an urban landscape

Species dynamics in an abandoned urban forest of Central Japan is described in this paper. The dominant species in the urban plantation were Cryptomeria japonica and Chamaecyparis obtusa. A variety of eight patches of the canopy was produced by previous forest management practices. Progressive and retrogressive species dynamics within these eight patches are investigated in this paper. The study elucidates the deterministic role of patchiness in the nature of species colonization and the maintenance of species diversity in an urban forest. Altogether 139 native and/or naturalized species, including 23 shrub and 35 tree species, were recorded in the study area of 3.2 ha. The performance of species varied according to their successional attributes indicating a selective canopy influence. Twenty percent of the tree species were shade-intolerant pioneers (e.g. Cornus spp., Rhus javanica var. roxburghii) re-established under selective tree-felling. Thirty percent were shade-tolerant climax species (e.g. Neolitsea sericea, Persea thunbergii) dominant in remnant closed patches. The remaining 50% belonged to various seral types with aggressive deciduous species (e.g. Aphananthe aspera, Celtis sinensis) in most of the patches. Some ruderal herbaceous species dominated heavily disturbed clear-felled patches. This study suggests that canopy modification influences the subsequent colonization pattern. Furthermore, heterogeneous patches contribute to greater species diversity and dynamics in isolated woodlands.