Sign up for the Slatest to get the most insightful analysis, criticism, and advice out there, delivered to your inbox daily. The late city planner Alexander Garvin used to tell his students at Yale about the genius of Frederick Law Olmsted’s Central Park Mall. With its canopy of interlocking elms, this promenade kept New Yorkers cool in the summer, but let them bask in the winter sun during the colder months. Olmsted’s genius, perhaps, but mostly the genius of deciduous trees, whose seasonal shade is perfectly aligned with the temperature preferences of the humans (and other animals) beneath. So why, as the United States bakes under another summer of heat waves driven by climate change, are they so few and far between on the streets of our cities? A National Shade Map, released last week by UCLA and the nonprofit American Forests, lets you explore some of the shade disparities between cities and neighborhoods on the summer solstice. Shading our sunniest neighborhoods would require planting 30 million trees. We are confronting a serious shade shortage. Much of it is by design. Trees have been banished from our roadways as just another “immovable fixed object” that poses a danger to drivers and obscures their sight lines. Canopies and awnings are subject to onerous permitting rules. Buildings have been extensively regulated to keep shade off the street. Unsurprisingly, the absence of shade maps neatly onto just about every other index of socioeconomic and racial division, and the temperature can vary by 30 degrees between sunny and shady parts of town. In a new book, Shade, Sam Bloch makes the case for rethinking our relationship with this “forgotten natural resource.” The most controversial piece of Bloch’s argument is that cities should embrace the shade cast by tall buildings. Skyscrapers are something like the opposite of Manhattan’s elms: They cast the most shade at the coolest hours of the day and year. A new “shade” layer on American Forests’ Tree Equity Map illustrates this phenomenon: At noon, almost all urban shade comes from trees. But as the afternoon goes on, tall buildings provide relief as well. An extreme example of this phenomenon can be seen in Paris, where narrow streets and six-story buildings make the streets so shady there’s a map to help Parisians find a terrasse in the sun. Shade-first city planning would upend more than a century of conventional wisdom about zoning. The early embrace of sunshine as an antiseptic, formalized in New York’s wedding cake towers that were required to step back gradually from the street, soon morphed into a generalized opposition to tall buildings. Shadow studies have killed tall buildings in San Francisco and New York. But more pernicious are all the local design guidelines that eschew sophisticated sun-path analyses for simple street width–to–building height ratios, regardless of where the sun is. When I spoke to him this week, Bloch pointed to Phoenix as a place that is taking shade seriously. In November, the city announced a $60 million investment in fulfilling the goals from a Shade Master Plan, which calls for trees and shade structures to be built around town. Few cities have been as focused on the benefits of shade as Los Angeles, where shade has been a popular topic at City Hall for the better part of a decade. There is not much to show for it, however. The great Sombrita debacle of 2023, in which Los Angeles held an ill-advised press conference to debut a bus-stop parasol the size of a skateboard, revealed how bureaucratic infighting made it hard to shade even a few square feet of sidewalk. Alissa Walker, whose newsletter Torched chronicles the efforts to heat-proof the 2028 Summer Olympics, wrote recently that she “tried to get a few parkway trees planted in the empty wells around our baked-asphalt elementary schoolyard, only to have the city, a local tree-planting nonprofit, and LAUSD all pointing fingers at each other like the Spiderman meme (and they’re still not planted!).” The issue is so emotional that when a homeless man calling himself an arborist cut down a dozen trees in downtown Los Angeles this spring, the act prompted a statement from Mayor Karen Bass, who called it “beyond comprehension.” The man faces more than six years in prison. Edith de Guzman and Monica Dean recently launched Shade LA, an organization that provides tools and resources to help Angelenos get their sunny city on a real program of tree planting. De Guzman, who also curated an art show called “Roots of Cool” about trees, noted that Los Angeles seems to actually shrink during the hotter months, as if recoiling from the sun. “It’s time to think about shade as civic infrastructure that should get a budget line item like roads and bridges,” she told me. What’s stopping us from building a shadier world? In warm-weather cities, the obstacles are prosaic. One is money. Especially in the arid Southwest, street trees require significant care to survive until their roots can reach water underground. Far from gearing up to spend more money on trees, L.A. is facing a billion-dollar budget deficit, and Donald Trump’s Cabinet is clawing back money for any projects related to climate or equity. The rules might be easier to address. You can’t plant a tree within 45 feet of an intersection in Los Angeles, for example, and there are other rules concerning a tree’s distance to driveways, telephone poles, and streetlights. “Every project we work on seems to have a protracted process of determining where [trees] can be placed to dodge other objects in the public way,” the architect Brian Lane wrote in 2022. “Half of what we (and our landscape architects) think is reasonable doesn’t end up working. There is literally so much urban junk (light poles, utilities, parking meters, driveways, etc) in the public way that it precludes the tree-lined avenues communities want and City Planners endorse.” A recent University of Southern California study found that loosening the city’s tree placement guidelines would increase potential tree density by as much as 26 percent. Planting the trees takes time, but the regulations can be changed tomorrow. In many northern climes, the public is still on the side of the sun, even if the winters aren’t as cold as they used to be. Perhaps we should also rethink our metaphorical invocation of sunlight (good) and shadow (bad). Laura Hartman, a professor of environmental studies at Roanoke College, recently developed a Bible study on urban heat that draws attention to moments of darkness in scripture, such as the description of God in the book of Isaiah as “a shade from the heat.” “These passages remind us that too much sun can be harmful, and that safety and comfort are to be found in the darker, shadier places,” she writes. “God may have separated the light from the dark in Genesis 1, but God declared them both to be good.”