The Value of Trees
The trees we live among are much more than beautiful. They do serious work and provide many concrete benefits.
- Trees make the air we breathe cleaner by producing oxygen and removing pollution.
- With their shade, they reduce the amount of energy that is needed to cool homes in summer.
- They collect carbon dioxide, a greenhouse gas, from the air and store it in their wood for decades or centuries.
- And much more!
To help us, trees need our care—planting, mulching, pruning, and watering. But it's worth it: Researchers have studied the benefits of trees and determined that for every $1 we invest annually in trees, we get about $2.70 back in benefits.
A Greener World
Trees improve air quality so we breathe cleaner air.
- Where there are plenty of trees, they reduce the air temperature. That reduces the emission of polluting volatile organic compounds from both plants and human sources, such as gasoline. And when the air is cooler, the ozone doesn't form as readily.
- Trees temporarily remove pollution from the air by catching tiny particles on their leaves and branches. Tree leaves also absorb gaseous pollutants.
Trees help us use less energy.
- Well-placed trees shade houses so it takes less energy to cool our homes in summer. Strategically placed trees save up to 56 percent on annual air-conditioning costs.
- Evergreens that block winter winds can save 3 percent on heating.
- Reduced energy demand means less pollution from coal-fired power plants and less dependence on nuclear power and natural gas.
Trees reduce water pollution.
- Trees intercept rain that falls on their leaves, stems, and bark, so less water from storms runs off into sewers.
- Less stormwater flowing into sewers means less polluted water must be treated, saving energy. The U.S. Forest Service estimates 100 mature trees intercept about 250,000 gallons of rainfall per year in their leafy crowns. Trees trap greenhouse gas.
- Trees collect carbon dioxide—which contributes to climate change—from the air and store it inside their wood.
- Through photosynthesis, trees turn carbon dioxide into fresh oxygen.
Trees keep cities cooler.
- Trees reduce the heat island effect—the storage and radiation of the sun's heat in paved or heavily built-up areas. The heat radiated from brick and concrete in heat islands such as cities and malls raise cooling costs and can trigger asthma and other lung problems. Trees reduce the heat island effect by shading concrete, asphalt, and other surfaces that would otherwise absorb heat from the sun.
- Trees also reduce the heat island effect by absorbing water from the ground and evaporating it back into the air—a process called "transpiration" that cools their surroundings. A 48-foot-tall sliver maple can transpire up to 58 gallons of water per hour.
Trees increase the value of homes and businesses.
- On average, each large front yard tree adds 1 percent to a house's sales price. Large trees can add 10 percent to property value.
- In tree-lined commercial districts, shoppers report more frequent shopping, longer shopping trips, and willingness to spend 12 percent more for goods.
Trees help people get along better.
- Tree planting programs give inner city neighborhoods a stronger sense of community and empowerment.
- Urban trees alleviate some of the hardships of inner-city living, especially in lower-income neighborhoods.
- 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 incivilities, fewer property crimes, and fewer violent crimes.
- More than 180 Illinois towns are proud to claim the title "Tree City USA."
Health and Happiness
Trees make us feel better.
- Studies show that when people can see or be near trees, they are more relaxed and less stressed.
- Hospital patients with window views of trees recover significantly faster and with fewer complications than patients who can't see trees.
- Around trees, children can focus and learn better.
- Urban trees and forests provide emotional and spiritual experiences that are important in people's lives.
Bigger is Better
- Large, healthy trees remove 60 to 70 times more pollution than small trees because they have more surface area in their leaves and bark to capture pollution particles and carbon dioxide.
- Coarse-textured or hairy leaves do a good job of trapping tiny pollution particles.
- Large, long-lived shade trees, such as oaks, provide the most benefits over time.
- A stately sugar maple or oak increases property value more than a smaller, multistemmed ornamental tree.
- Since they keep their leaves in winter, evergreens work year-round, capturing rainwater, producing oxygen and cleaning the air.
Most facts are summarized from Trees Pay Us Back by the U.S. Forest Service and "The Role of Our Urban Forest in the Chicago Metropolitan Region's Future," October 2010.
Bring attention to trees in your community!
Your class or community group can highlight the importance of trees by tagging them. Our Tree Tagging Kit makes it a fun, easy project. The free kit was developed by the Education and Community Trees Program at The Morton Arboretum. Each Tree Tagging Kit includes:
- 20 Tree Tags
- Twine for hanging tags
- Links to lesson plans for grades three-12
- Website links to help identify trees
- Reproducible "Benefits of Trees" handout
- Invasive Pest information
- sample press release