Fragmentation effects on the structure of some urban forests in Istanbul

Forest fragmentation is the separation or division of large forests into smaller units. Areas with non-forest lands significantly threaten the health, function, and value of the remaining forest. This study describes the effects of fragmentation on diversity of forest in the city of Istanbul. We obtained inventory data from local forest management and silvicultural plans (2002-2007). The data were used to determine the spatial variation in forest structure and biodiversity across six urban forest fragments in Istanbul, Turkey. We calculated a core set of patch- and class-level metrics in order to predict forest basal area within sample plots. We tested a number of regression models and employed the best-fitted model to extrapolate forest diversity across the urban forest fragments. Results indicate consistent relationship between spatial and silvicultural variables, suggesting the impact of fragmentation on the forest structure and biodiversity in Istanbul. Species richness of green spaces in urban areas was higher when compared to that of peri-urban areas. The location and the sizes of urban forests were associated with difference in societal expectations from these areas. As a consequence of the expectations, there was a change in forest structure in Istanbul. This study could be conducted for any other urban areas including large growing cities and megalopolis.