Urban forestry for cooler cities faces three critical hurdles

Urban trees can protect city residents from extreme heat, but tree planting programs seldom provide sufficient shade where it is most needed. We synthesize evidence highlighting three rarely fulfilled prerequisites for the effective use of trees in heat adaptation. Urban forests are a critical tool for heat adaptation, but often underperform for three reasons. Trees must be healthy (not thirsty or soil-constrained), densely planted, and carefully protected from premature removal to deliver effective cooling in urban settings.