Influence of tree management (pruning, irrigation) on growth and ecosystem service provision of Platanus x acerifolia

Urban trees grow in a very heterogeneous environment. In addition to the demanding growing conditions due to small planting pits with limited rooting space and sparce water availability, heat, pollution and much more, above-ground space requirements because of safety reasons and aesthetic demands affect urban tree growth. Management practices such as pruning are a common measure for many urban tree species to adjust the crown for aesthetic requirements and size constraints such as buildings, other trees or above ground cables. On the other hand, these pruning measures alter tree growth and thus ecosystem services such as cooling, CO2 sequestration and runoff reduction. To maintain or improve growth and the provision of ecosystem services despite the challenging conditions in urban environments, trees can be irrigated, particularly during periods of drought. Our research analyzes the influence of management (pruning and irrigation) on tree growth and the provision of ecosystem services such as cooling on the common urban tree species Platanus x acerifolia in cities. Plane trees are often selected for aesthetic pruning due to their high pruning tolerance, robustness and fast growth. For this study, the tree structures more than 350 pruned and unpruned trees in Munich and in a tree nursery were measured and their growth conditions compared. The modeling tool CityTree was used to calculate the biomass accumulation and provided ecosystem services carbon storage and cooling by shading and transpiration of pruned and unpruned trees, with and without irrigation. The results show clear differences in growth, tree parameters such as leaf area, biomass, photosynthesis and provision of ecosystem services between pruned and unpruned trees, with irrigation helping to survive drought periods. The results can be useful for urban planners regarding management practices in urban tree planning to create more efficient management plans and increase the vitality of urban trees.