Effects of urban tree pruning on ecosystem services performance

Pruning represents the main tree care activity in cities, where it is carried out to reduce wind-break risk, to ensure road visibility, to reduce infrastructure interactions and damages, and last but not least, for aesthetic reasons. However, pruning is also proven to increase tree susceptibility to disease and it can potentially affect their capacity to provide ecosystem services (ES). This study aims to assess the effect of three different life-long pruning scenarios on urban trees PM10 capture and CO2 stock performance. The total carbon balance of twelve tree species (Acer platanoides L., Cedrus spp., Celtis australis L., Cupressus arizonica Greene, Cupressus sempervirens L., Pinus halepensis Mill., Pinus nigra J.F. Arnold, Pinus pinea L. Platanus hybrida Brot., Populus nigra L. var. 'Italica', Quercus ilex L., and Tilia cordata Mill.) was evaluated, including the disposal of the pruning residues of the trees. In all management scenarios studied, pruning represented an opportunity to increase the crown Carbon stock up to 65 %, taking into account the full reestablishment of the crown. The results suggest considering more frequent and less intense ordinary pruning scenarios as a preferable tree management strategy to optimise the tree ES performance and minimise branch dieback occurrence. In addition, the analysis carried out on four different waste wood disposal methods showed that the open dump scenario was the lowest CO2 eq re-emission choice.