Aside from providing oxygen and beautifying our cities, trees help keep us cool. With up to 80% of the US population living in urban and suburban environments, trees are a little slice of nature in concrete landscapes. As summers get hotter and hotter, an abundance of trees in urban landscapes has been shown to drop the temperature by as much as 10 degrees Fahrenheit.
Unfortunately, our trees are not safe. The US Forest Service study found that we lost 36 million trees annually from urban and rural communities over a five-year period. Rising temperatures, insects, disease, and other natural disasters shoulder some of the blame, but there is also the push to use every available space. So trees are being removed and replaced by parking lots and towers.
If we continue on this path, "cities will become warmer, more polluted and generally more unhealthy for inhabitants," said David Nowak, a senior US Forest Service scientist and co-author of the study.
"We see the tree cover being swapped out for impervious cover, which means when we look at the photographs, what was there is now replaced with a parking lot or a building," Nowak said.
"Every time we put a road down, we put a building and we cut a tree or add a tree, it not only affects that site, it affects the region."
Trees provide many vital beneifts to an urban landscape. They provide shelter on hot days, they help clean their air from pollutants , and they help reduce energy emissions by lowering air conditioning costs. In addition, they help soak up excess rain from flooding, they help protect from UV radiation, and they're a big buffer for soaking up the noise of the city. Finally, they give birds a place to roost and they help provide psychological comfort to urban dwellers.
So there are tremendous benefits to designing and managing tree canopies in our cities to help "affect the air, to affect the water, to affect our well-being." But it does require actual effort on the part of the government and citizens to plant and maintain the trees. Organizations like Trees Atlanta in Atlanta, GA have volunteers planting and maintaining young saplings.
"We try to prune trees for 10 years to make sure they get a good healthy structure." Greg Levine, co-executive director for Trees Atlanta, says. "We also add mulch around trees to help keep the moisture in the ground so the tree doesn't dry up. We have to have a lot of patience with planting trees around pavement, making sure that they can rise to the challenge. "
If you want to get involved, there are some things you can do to help. Clean and prune dead limbs, allow trees to grow on your property, tend to the trees you regularly pass by, and educate yourself on what the natural spaces in you community need.