Structural soils are a type of designed soil intended to improve tree growth in the built environment by increasing the rooting volume available to trees underneath pavement. While urban trees can experience multiple environmental stressors, tree water relations and leaf nutrients are not well studied in structural soil systems. We examined leaf level gas exchange, foliar nutrient concentrations, and crown condition to evaluate the potential effects of water and nutrient related stressors in this setting. Located in Brooklyn, NY, USA, the study site included Quercus bicolor and Q. phellos planted in both sidewalk pits underlain with structural soil and in open lawn areas. Tree size measurements indicate that around 16–20 years post-installation, lawn trees have started to become larger than those in the sidewalk, though the size differences are comparatively small. Leaf level net photosynthetic assimilation and stomatal conductance of Q. bicolor were significantly lower in sidewalk trees compared to lawn trees in 2016. Yet no differences in gas exchange were observed for Q. phellos which suggests the two species likely have different water use strategies. Out of 27 elements measured in leaf tissue, Ca, K, Ba, and Sr were significantly lower in Q. bicolor sidewalk trees. Both species appeared to have elevated foliar concentrations of Na. For Q. phellos, sidewalk trees had significantly lower crown vitality (fine twig dieback) scores, though no differences were observed for Q. bicolor. These findings suggest Q. bicolor may be more sensitive to water and nutrient stress in the structural soil system compared to Q. phellos.