Woodlands across Swedish urban gradients: Status, structure and management implications

More than 70% of the European population live in urban areas, and the level of urbanisation is steadily increasing. As a result urban and peri-urban woodlands are decreasing due to infill development within cities and sprawl (or expansion) outside cities, respectively. However, comparative assessments of urban woodland resources at international and national levels are lacking. We used GIS analyses to quantify the proportion of urban woodlands in 100 Swedish cities with >10 000 inhabitants. Field surveys were used to measure vegetation structure in 474 urban woodlands across an urban gradient in a subset of 34 cities. Our results showed that the proportion of the city area comprised of urban woodland varied between 1 and 40% with an average of 20%. Commuter cities close to the largest cities and cities with stable populations had higher proportion of urban woodland than cities with large population increase. Urban and peri-urban woodlands cover an area larger than the total area of protected forests in Sweden and had higher amounts of dead wood than typical non-protected forests. Thus, these woodlands are potential areas supporting conservation of species depending on dead wood. Commuter cities are expected to have a large population increase in the upcoming years, which may lead to further fragmentation of urban woodlands in these cities. Management greatly affected the vegetation structure in woodlands across the urban gradient, and decision makers and urban planners need to be informed about the ecological consequences of different management actions.