Plant and Protect

Benefits of Trees

Trees make the world better for people today and for generations to come.

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Over the past 30 years, science has demonstrated how trees provide many concrete benefits for people, society, and the environment.

Numerous scientific studies have shown that trees promote health and well‐being by reducing air pollution, encouraging physical activity, enhancing mental health, promoting social ties, and even strengthening the economy. As the world faces growing concerns about climate change—including rising temperatures and more frequent and more extreme weather events—it’s helpful to know that trees can contribute to reducing urban temperatures and provide the necessary infrastructure to support the management of stormwater.

To provide these benefits and more, trees need care—planting, mulching, pruning, and watering. It’s worth the time and money: experts have determined that every dollar invested in tree planting and management returns up to 500%. Trees also provide an estimated $18.3 billion in annual value of air pollution removal, reduced building energy use, carbon sequestration, and avoided pollutant emissions. Allocating resources for tree planting and maintenance is more than just a fiscally sound decision; it is an investment in the very well-being of people and the planet.

How Trees Help the Bottom Line

Experts suggest that every dollar invested in tree planting and management returns up to 500%. Trees provide important benefits with economic value, such as reduced energy costs associated with heating and cooling, increased home and real estate values, enhanced consumer satisfaction, and life-sustaining shelter and nourishment.

Trees reduce heating and cooling bills by saving energy. The right tree can lead to reduced energy use, lowering the cost of utility bills by naturally cooling a home during the summer months and providing shelter from cold in the winter months. For example, evergreens that block winter winds can save 3% on heating. This reduction also means that fewer greenhouse gases need to be produced in generating power.

Trees increase home values. Homes in neighborhoods with mature trees sell for at least 10% more than in neighborhoods without trees. On average, each large front yard tree adds 1% to a house’s sales price and large trees can add up to 10% to the property value. Trees and quality landscaping have also been shown to increase rental rates for office buildings. And the presence of shade trees reduces the rate of wear and tear on roads and pavement surfaces, keeping infrastructure repair costs down.

Trees are good for business. Research shows that shoppers respond to the overall aesthetics of their shopping experience; they will travel farther to shop in tree-lined business districts and tend to spend more time and money once they are there. In tree-lined commercial districts, shoppers report more frequent shopping, longer shopping trips, and willingness to spend 12% more for goods.

Trees pay dividends. The many contributions of trees have substantial economic benefits. Each year, the more than 157 million trees in the seven-county Chicago region provide services that have an estimated total worth of $195 million by capturing air pollution, storing carbon, and reducing energy costs. Urban street trees provide invaluable resources to communities, helping them to survive and thrive, even in areas of economic scarcity. In New York City, 88% of public tree species can be foraged for either food or medicinal use, including nine out of ten of the most common tree species.

How Trees Help the Environment

Trees clean the air people breathe. Air pollution (from carbon monoxide, particulate matter, polycyclic aromatic hydrocarbons, nitrogen dioxide, sulfur dioxide, and other compounds) has been linked to numerous health issues, including bronchitis, glaucoma, autism, blood pressure, cognitive developmental problems in children, and heart failure. Trees can mitigate these effects by removing pollution from the environments. Trees, especially strategically planted mature species, can reduce particulate matter and other forms of air pollution, which can reduce mortality and morbidity in urban centers. In the United States alone, urban trees remove 822,000 metric tons of pollution per year. The more trees we plant–given the proper placement and care–the more pollution they can absorb to benefit human health.

Trees treat water pollution. Because trees slow down water flow and can absorb waterborne toxic waste and then neutralize, metabolize, or vaporize it, they operate as extremely effective natural water filters. The root systems of trees can collect contaminants as water seeps through the soil, reducing the negative impacts of pollution-laden sediments, and some trees are able to uptake contaminants and store it in their woody tissue. Research shows that river basins with the greatest amount of farmland produce the most water pollution, while river valleys with the most forest coverage produce the least. Nitrogen and phosphorus from fertilizers and factory-farmed animal waste encourage the proliferation of bacteria that consume oxygen dissolved in the water. Deforestation along waterways contributes to faster rates of water flow, reducing the amount of time and trees available for absorbing contaminants from the water.

Trees help handle storm runoff and reduce flooding. During heavy rainstorms, the roots of trees soak up and filter stormwater. Trees collect raindrops on their leaves, where the water can evaporate. These actions can greatly reduce the volume of water that enters storm sewers, which diminishes the risk of flooding and the amount of sewage-polluted stormwater that cities must treat. The US Forest Service estimates that 100 mature trees intercept about 250,000 gallons of rainfall per year in their leafy crowns.

Trees can mitigate the effects of a changing climate. Climate change can directly impact all aspects of human life, including increasing heat‐related deaths and aggravating the severity of storms. Strategic urban tree planting can help lower temperatures in built environments and reduce environmental stressors, such as excess flooding and pollution. Not only do trees provide shade through absorbing light, but through evapotranspiration trees actively cool the air. In fact, trees incorporated into the built environment can reduce a city’s temperature by as much as 9°C. This reduction of temperature in urban centers can help ameliorate the impact of climate change on human health.

Trees store carbon, a major contributor to climate change, and the more mature a tree is, the more carbon it can store. Research has shown that urban trees in the United States sequester some 22.8 million tons of carbon each year and that the urban forest in this area stores 700 million tons of carbon. Although trees are not the only answer to the problems posed by climate change, they can help mitigate the problem.

How Trees Help People’s Health

Trees give oxygen. Through photosynthesis, trees turn carbon dioxide into the oxygen we need to live.

Trees save lives. By capturing fine particles of air pollution, urban trees and forests are saving an average of one life every year in each of 10 U.S. cities, according to a recent study. In New York City, for example, trees save an average of eight lives every year. Trees catch tiny particles from the air on their leaves and branches.

Trees make people healthier. There is a documented link between trees, green spaces, and mortality rates. Residents of tree‐lined communities have reported feeling healthier and been shown to have fewer cardio‐metabolic conditions than their counterparts; they are more likely to be physically active and less likely to be overweight or obese. Trees have been strongly linked to reduced symptoms of depression and increased life satisfaction. The presence of trees has also been proven to improve the condition of people with neurodegenerative disease.

How Trees Make People’s Lives Better

Trees help people relax. The sight of trees reduces blood pressure and helps people to be more productive. Exposure to trees and nature reduces children’s stress, which can reduce symptoms of attention deficit disorder. Drivers who can see trees and nature are less frustrated. A view of trees can help hospital patients recover more quickly and has been shown to reduce diastolic blood pressure and stress.

Trees keep people cooler. By casting shade and giving off moisture from its leaves, a big shade tree can reduce the surrounding temperature by 10 to 15 degrees. In cities, planting a large amount of trees can reduce the “heat island effect” caused by heat stored in paving and masonry buildings.

Trees make streets quieter. Trees reduce noise by absorbing sound, especially at high frequencies. A band of trees and shrubs planted on a raised berm can reduce highway noise by 6 to 10 decibels.

Trees make cities safer. On a community-wide level, the presence of trees in urban neighborhoods has been linked to reducing aggression and lowering criminal activity. In city areas with nearby trees and natural landscapes, there is less domestic violence. On tree-lined streets, people drive more slowly, reducing accident risk. Studies have shown that trees contribute to stronger ties among neighbors, a greater sense of safety, closer supervision of children in outdoor places, healthier patterns of children’s play, more use of neighborhood common spaces, fewer property crimes, and fewer violent crimes. Adolescents in urban communities may display less aggressive behavior if they live in neighborhoods with more greenery. And some studies suggest that the presence of trees simply makes urban residents feel safer overall.

Trees surround people in beauty. Green in summer, golden in fall, lovely even in winter when their branches are outlined with snow, and glorious in spring, trees bring life to city streets and grandeur to suburban boulevards. Without trees, neighborhoods would be stark and lifeless. Without trees, the horizon would be empty. Without the woods, where would the trail go?

Sources

To learn more about how research demonstrates the value of trees, see these sources: