CARBON REMOVAL

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• The energy saved by trees and the resultant reduced demand for power, lowers the carbon dioxide emissions from power plants.

• A hypothetical planting of 100 million trees would save 22 billion kilowatt-hours of energy and 33 million tons of carbon dioxide annually after 10 years (Akbari, 1990).

• Reduction of carbon dioxide with urban shade tree programs could offset 0.2 - 2% of annual industrial emissions.

• Portland’s Friends of the Trees has planted over 300,000 trees. Once mature, their surviving trees and seedlings are estimated to sequester 73,000 tons of carbon dioxide at a cost of about $31 per ton.

• A single, mature Bradford pear tree has measured storage of 676 pounds of carbon dioxide in above-ground biomass.

 

 

SOIL SEQUESTRATION

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• In a mid-sized city, nearly 11,000 tons of soil are saved annually with tree cover.  

• Roots reduce soil compaction, increasing the rate at which rainfall infiltrates soil and the capacity of soil to store water, reducing overland flow.

• Decaying leaves form an organic ground layer allows water to percolate into the soil, reducing runoff and soil erosion. The leaves also act as mulch and reduce evaporation; a critical concern in times of low rainfall.

• Trees reduce soil erosion by diminishing the impact of raindrops on barren surfaces.

• Trees and other plants help remediate soils at landfills and other contaminated sites by absorbing, transforming, and containing a number of contaminants.

 

 

HEALTH BENEFITS​

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• Hospital studies have shown quicker patient recovery when patients have a view of urban canopy, trees, and greenery.

• Trees have been shown to have calming and healing effects on ADHD adults and teens.

• Urban trees enhance relaxation and improve a sense of well-being.

• Trees' absorptive effect of tailpipe pollutants, including carbon monoxide (CO), volatile organic compounds (VOC), nitrogen oxides (NOx), and particulate matter (PM) has direct health benefits.

• Trees shield children from ultra-violet exposure by 50%.

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COMMUNITY ENRICHMENT​ & SOCIAL BENEFITS

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• Recreation areas such as parks, greenways, and river corridors that are well stocked with trees tend to keep recreation seekers “at home” rather than driving many miles to find suitable places to enjoy leisure activities. With less fuel used, less pollution is created. It would be difficult to put a dollar value on robust urban playgrounds, but if each visit were valued at only one dollar, the annual total for the typical city would be in the thousands.

• An abundance of trees presents a more appealing community to newcomers and residents.

• More shade means more time between repaving. With just 20% shade, pavement conditions improve by 11%; a 60% savings for resurfacing in 30 years (Greg McPherson, 2008).

• Trees reduce storm runoff and erosion by nearly 7% and reduce the need for erosion control structures. In urban areas with trees, the use of smaller drainpipes can save city materials, installation, and maintenance funds.

• Residents that live near urban trees have better relations and stronger ties to their neighbors (Building Safety Division, Culver City).

• Active involvement in tree-planting programs has been shown to enhance a community’s sense of social identity, self-esteem and territoriality, as it teaches residents that they can work together to choose and control conditions of their environment. Tree planting programs also teach children about the environment as a commitment to the future.

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REAL ESTATE

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• The value of houses with trees is usually higher than comparable houses on lots without trees.

• Each large front yard tree adds 1% to a sale’s price. Large specimen trees can add up to 10% to property values (Greg McPherson, 2008), while property values increase 5-15% compared to properties without trees (species, maturity, quantity, and location vary).

• A tree in front of a house increases the home's sales price by an average of $7,130, according to the PNW Research Station.

• Apartments and offices in wooded areas rent more quickly, have higher occupancy rates, and tenants stay longer (The Morton Arboretum Press Release, 2019).

• Well-placed trees substitute for fences and provide privacy. In some areas, zoning ordinances restrict fences on property lines; suitable trees may make a more appealing and natural substitute.

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WILDLIFE HABITAT

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• The lowest bird diversity is in areas of mowed lawn, while the highest is in an area of large trees, tree diversity, and brushy areas.

• The highest native bird populations are in areas of highest native plant populations, thus it is important to plant native trees in urban areas to enhance natural habitats.

• Trees are living systems that interact with other living things in sharing and recycling resources.  

• The National Wildlife Federation recognized the benefits of trees in sustaining wildlife by certifying homes, schools and community settings as Certified Wildlife Habitats.

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BUSINESS BENEFITS

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• Studies have shown that shoppers linger longer and make more frequent trips to shopping strips along a shaded avenue than compared to one barren of trees.

• Research shows that shoppers in well-landscaped business districts are willing to pay more for parking and up to 12% more for goods and services (The Morton Arboretum Press Release, 2019).

• Shaded thoroughfares are considered more physically comfortable and psychologically more attractive.

• Businesses leasing office space in wooded developments find their workers are more productive.

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NOISE REDUCTION

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• Although wide belts of trees in an urban setting are unlikely, there is a 7db noise reduction (about 50%) per 100 feet of forest due to trees by reflecting and absorbing sound energy (USDA National Agroforestry Center).

• Trees provide “white noise,” the noise of the leaves and branches in the wind and associated natural sounds, that masks other man-caused sounds.

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WATER CONTROL

 

• Computer simulations of deciduous trees in California’s Central Valley estimate that for every 1000 trees, rainwater runoff is reduced by nearly 1 million gallons.

• Reduced runoff directly reduces flooding in the streets.

• A secondary effect of the reduced runoff is s reduction of dirt washed into lakes, rivers and the ocean, which reduces sedimentation. Reduced runoff also means that heavy metals and other pollutants from roads, parking lots, and roofs are not carried into our water supply. This, in turn, reduces the load on water treatment facilities.

• The American Society of Landscape Architects has produced some informative animated videos on the benefits of proper landscaping for water management. Native trees are a part of their water management plans.

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ENERGY CONSERVATION

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• A tree shading a home air conditioner, but not blocking its airflow, has been estimated to improve its efficiency by 10% (Coder, 1966).

• An appropriate shade tree planted today on the west side of a home can reduce air conditioning energy bills by 3% after five years. In 15 years, the savings will be nearly 12%. An equal east side planting can warrant a combined energy savings of up to 23%.

• Three or more large trees placed on sunny sides of a house shade it from the hot summer sun. Deciduous trees are best for this use because they lose their leaves in winter, exposing the house to the warming winter sun, thus lowering the energy needed to heat the house. Coniferous trees make good screens and serve as windbreaks when placed in the path of the prevailing winds because they retain their needles year-round.

• Trees can create a reduced wind or still area and lower winter cold air infiltration and exchange in a house.

• Shade from the establishment of 100 million mature trees appropriately placed around residences (three per residence) in the United States is estimated to save about $2 billion annually in reduced energy costs (Akbari et al. 1992; Donovan and Butry, 2009).

• Data from the USDA shows that 50 million shade trees planted in strategic, energy-saving locations could eliminate the need for seven 100-megawatt power plants. Trees planted in these numbers will reduce the summertime peak demand that has led to increased prices and potential blackout.

• Evaporation from tree leaves cools the air resulting in further reduction of summer air conditioning costs (Coder, 1966).

• Want more info: The American Association of Landscape Architects has created an animated video of the energy benefits of trees that makes tree placement, function, and use of trees for seasonal shade and wind control understandable.

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AIR QUALITY

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• One acre of trees generates enough oxygen each day for 18 people.

• Trees absorb gaseous pollutants into their leaves and trap and filter particulates on and through their leaves, stems, and twigs. Pollutants partially controlled by trees include nitrogen oxides, sulfur dioxides, carbon monoxide, carbon dioxide (required for normal tree function), ozone, and small particulates less than 10 microns in size (Irga, Burchett, & Torpy, 2015).

• Trees lower local air temperatures (reduce urban “heat island” effects) by transpiring water, shading surfaces and reducing cooling costs, energy use and the resulting pollution.

• In 1994, trees in San Diego removed an estimated 1,260 metric tons of air pollution at an estimated value to society of $7.0 million (Air pollution removal by urban trees and shrubs in the United States, Nowak, Crane, Stevens, 1994).

• Want to learn more: The American Society of Landscape Architects has created an animated video that visually presents the benefits of urban forest for creating cleaner and cooler air.

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OTHER BENEFITS

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• Trees provide food for birds, wildlife, and people. 

• Trees provide wood that can be crafted into furniture, instruments, and art.

• Trees block unsightly views such as concrete walls and parking lots.

• Trees are landmarks that can give places new identities and encourage civic pride.

• Tree planting brings communities together.

• Trees provide space for human retreat.

• Trees and landscaping help reduce violence and fear.

• Trees mark the seasons.​