Feeling Hot? Plant a Tree.

Everyone has noticed that a hot day in a city is a special kind of hell. Most cities' temperatures range from 1° to 7° F hotter than their surrounding countryside. This effect is called an urban heat island. Cities are hotter because concrete, asphalt, brick, steel, and roofing materials all hold heat. The most intuitive solution to heat islands is also the most effective: making the city more like the country, by planting trees. A recent study shows that on a hot day, tree-lined streets can be as much as 3.48° F cooler. Even better, adding more trees—just 20—can cool an entire neighborhood by 1.39° F.

New York City surface temperature map from NASA. Can you tell where the parks are?

Climate crisis means hotter cities. Over 500 people in the Pacific Northwest and Canada died in connection with the recent historic heat wave. Adding tree cover will help mitigate this kind of threat. Cooler cities also mean people won't have to turn on their A/C's as early, lightening the burden on our straining (and privatized) power-grids. On an economic level, the EPA has found that every dollar invested in urban trees provides $1.50 to $3 of benefits.

Trees do so much more. Trees reduce noise pollution, prevent soil erosion, provide animal habitat, and prevent rainfall waste by keeping water in our neighborhoods. But perhaps it is enough for us that trees just make us happy, and remind us of our connection to nature.

Boost our immune systems

• Reduce heart rate and blood pressure

• Improve mood

• Provide shade from UV rays

• Clean pollutants out of the air

• Patients recover from surgery faster and better when they have a "green" view.