American cities lose 36 million trees each year. Here’s why it’s important and how you can stop it

If you are looking for a reason to care about tree damage, record breaking heat waves can occur this summer. According to a recent study, trees can reduce summer day temperatures by up to 10 degrees Fahrenheit.

But tree cover is shrinking in American cities. A study published last year by the U.S. Forest Service found that 36 million trees a year were lost from urban and rural communities over a five-year period. This is a 1% decline from 2009 to 2014.

“If we walk this path, cities will become warmer, more polluted and more unhealthy for residents in general,” said David Novak, a senior scientist with the U.S. Forest Service and co-author of the study.

Novak said there are many reasons for our tree umbrella to fall, including hurricanes, tornadoes, fires, insects and disease. But one reason for the loss of a tree that humans can control is proper development.

Novak said, “We see that the tree cover has been changed for impassable cover, which means that when we look at the photos, what was there has now been replaced by a parking lot or building.”

More than 80% of the U.S. population lives in urban areas, Novak said, and most Americans live in forested areas along the east and west coasts.

“Every time we build a road, we plant a building and we cut down a tree or add a tree, which not only affects the site, it affects the area.”

This study gave a value to tree damage based on the role of trees in air pollution removal and energy conservation.

Heat reduction: Trees provide shade for houses, office buildings, parks and roads, cooling surface temperatures. They take in water and evaporate, cooling the air around them. Novak said, “Walk in the shade of a tree on a hot day. You can’t get it through the grass.” According to a recent study in the Proceedings of the National Academy of Sciences, tree canopy cover must be above 40% cool to achieve absolute temperature gains. The authors write, “A city block requires up to half of the twigs and leafy green network.”

Reduction in air pollution: Trees absorb carbon and remove pollutants from the atmosphere.

Reduction in energy emissions: According to a study by Novak, trees reduce energy expenditure by 4 billion billion a year. “Shading those trees on buildings will reduce your air conditioning costs. Remove those trees; now that your buildings are warming up, you are running your air conditioning more and you are burning more fuel from power plants, so pollution and emissions will increase.”

Improving water quality: Trees act as water filters, absorb dirty surface water and absorb nitrogen and phosphorus from the soil.

Flood mitigation: Trees reduce flooding by absorbing water and flowing into streams.

Noise reduction: Trees can scatter sound, you see them in the middle of roads, fences and streets and neighborhoods. They can also add sound through the pranks of birds and the sounds of the air flowing through the leaves, showing mental benefits.

Protection from UV radiation: Trees absorb 96% of ultraviolet radiation, Novak said.

Good Aesthetics: Ask any real estate agent, architect or city planner: Tree and leaf covers can enhance the look and value of any property.

Good human health: Numerous studies have found a link between exposure to nature and improved mental and physical health. As a result of these studies some hospitals have added gardens and orchards to patients. Doctors are advising children and families to walk in nature as there is evidence that exposure to nature can lower blood pressure and stress hormones. And studies have linked living near green areas with a lower mortality rate.

Wildlife Habitat: Birds rely on trees for shelter, food and nest. Around the world, forests provide a wide variety of animals.