Urban trees provide a range of ecosystem services, but their effects on stormwater runoff volumes and water quality are largely overlooked due to limited data. Researchers at the University of Minnesota undertook a three-year project monitoring tree-scale water quantity and quality fluxes across Saint Paul, Minnesota, examining how local measurements related to watershed-level observations citywide. The study quantified canopy interception, transpiration and nutrient fluxes in canopy throughfall across multiple species and sites. Under most species, canopy throughfall was statistically lower than open precipitation. However, mean soluble reactive phosphorus and total organic carbon fluxes were significantly higher under ash and maple trees than in open precipitation during spring and summer seasons between 2022 and 2024, despite lower overall water volumes. At the watershed scale, the two of five urban watersheds with the highest street tree coverage showed higher phosphorus fluxes across all seasons, suggesting deciduous street tree canopy influences nutrient concentrations at both storm-event and seasonal timescales.