ECOSYSTEM SERVICES IN URBAN PARKS: A CASE STUDY OF SLOTTSSKOGEN

Abstract

Urban areas have grown substantially over the last century and are on course to being the overwhelming setting by which most people on our planet live. With urbanisation comes disproportionate environmental and anthropogenic impacts on the local, regional, and global scale. Challenges with urbanisation include air pollution, weakening storm water drainage, habitat loss, urban tree cover regression and more. Urban ecosystems, like parks, are therefore becoming increasingly important to the health and well-being of cities residents and the environment. Parks and other green spaces have the ability to provide vital ecosystem services such as storm water mitigation, pollution removal, carbon storage and carbon sequestration along with human health benefits in the form of recreational use, improved mental health, physical wellbeing and more. The main objective of this thesis was to quantify and describe the ecosystem services provided by Slottsskogen, a park in central Gothenburg, to the municipalities residents. To achieve this, the i-Tree Eco model was used to quantify ecosystem services based on tree characteristics along with a qualitative approach based in expert opinion and relevant literature. This study utilised an inventory of the trees of Slottsskogen conducted by NärNaturen-VästSverige AB and Jacksons Trädvård Sydväst AB at the request of Stadsmiljöförvaltningen. The inventory included diameter at breast height and species type for all trees studied. By encompassing new tree characteristics such as tree height, crown diameter and base crown height in a new inventory of 29 trees we were successful in comparing i-Tree Eco estimates between inventories. We found differences in the data output for pollution removal and runoff mitigation between the inventories but none for carbon storage and carbon sequestration. This study also uncovered differences in i-Tree Eco estimates on a species basis and with regard to tree size and other characteristics. Furthermore, we found that allometric relationships between tree characteristics (diameter at breast height, tree height, crown diameter) have strong statistical correlations with each other. This indicates that the different tree characteristics provide similar input to modelling estimates. The results of this study may be of interest to the City of Gothenburg in their work with preserving the services contributed by urban green spaces along with providing a basis for decision-making processes. The main findings from this study demonstrated that the inventoried trees of Slottsskogen provide ecosystem services in the form of carbon storage and sequestration, runoff mitigation, pollution avoidance along with qualitative services such as mental and physical health benefits to the residents of Gothenburg and beyond.