Street tree stormwater control measures can reduce runoff but may not benefit established trees

Abstract

Directing stormwater runoff to irrigate urban trees has the potential to simultaneously: (i) reduce the volume of runoff generated by impervious surfaces and (ii) reduce tree drought stress and increase growth. Many papers promote this concept, but few have quantified both potential benefits. In this study, we quantified both the runoff retention performance of infiltration trenches retrofitted alongside established street trees and tree drought stress and growth. We compared retention for different soil types, tree phenological types and inlet designs over a period of 18 months. Retention was low on average (18.3%) but was highly variable among infiltration trenches (5.2–43.7%), driven by v..