When city planners in Rennfield proposed lining every downtown avenue with maples, they justified the expense with a single promise: shade would lower summer temperatures enough to cut air-conditioning bills across the district. The council's report leaned heavily on a study from a coastal town where newly planted oaks coincided with a 12 percent drop in residential energy use over five years. Critics noted, however, that the coastal town had also replaced its aging power grid and subsidized efficient appliances during those same years. They argued that the report treated a tangle of causes as if a single thread—the trees—had done all the pulling. Supporters countered that shade physically blocks sunlight from striking pavement and walls, a mechanism no grid upgrade could explain. Yet even they conceded that maples, unlike the coastal oaks, drop their leaves by October, offering no barrier during the shoulder months when Rennfield's cooling season begins. The debate, one columnist wrote, had become less about whether trees cool a city than about whether this particular plan, in this particular climate, would deliver the savings its price tag assumed.