This story was originally published by the Guardian and is reproduced here as part of the Climate Desk collaboration. It was a relatively cool spring day in Phoenix, Arizona, as a tree-planting crew dug large holes in one of the desert city’s hottest and least shaded neighborhoods. Still, it was sweaty backbreaking work as they carefully positioned, watered and staked a 10ft tall Blue palo verde and Chilean mesquite in opposite corners of resident Ana Cordoba’s dusty unshaded backyard. “If I ever retire, I’d like to be able to spend more time outside.