Assistant Professor of Urban Planning V. Kelly Turner spoke to Popular Science about local government campaigns to plant trees to mitigate rising urban temperatures. In Los Angeles, for example, Mayor Eric Garcetti’s “Green New Deal” from 2019 calls for the planting and maintenance of 90,000 trees by this year. Turner said the effectiveness of this type of climate intervention depends on many factors. “I think that there’s typically this sort of blind faith that we place in trees, that they will provide all of these wonderful social benefits,” she said. “But the environmental benefits that trees provide are entirely context-dependent.” It takes years for trees to mature into full-fledged shade-providers, so there is much to learn about the success of this type of  initiative. In the future, Turner said, cities will need to ask not only if they hit a numerical goal for planting trees but how well those trees brought about the cooling benefits that the community needs.