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Each of our tree specimen inventory pages utilizes the "Tree Benefit" formula to determine both the financial and ecological benefits of trees found at the Yellowstone Arboretum. You can utilize the benefit calculator by accessing the tree benefits website here:


The tree Benefit Calculator allows anyone to calculate a first-order approximation of the benefits individual street-side or parkland trees provide. This tool is based on i-Tree’s street tree assessment tool called STREETS. With minimal inputs of location, species and tree size, users will get an understanding of the environmental and economic value trees provide on an annual basis.

The Tree Benefit Calculator is intended to be simple and accessible. As such, this tool should be considered a starting point for understanding trees’ value in the community rather than a scientific accounting of precise values. For more detailed information on urban and community forest assessments, visit the i-Tree website.

    •    The National Tree Benefit Calculator was conceived and developed by Casey Trees and Davey Tree Expert Co.
    •    This tool is powered by i-Tree; the data generating the results comes from the i-Tree Tools CD ROM:
    •    Significant text and graphical content was originally published by the USDA Forest Service’s Center for Urban Forest Research through their Tree Guide series of publications. Credit should be given to authors of these publications.
    •    Facts about personal carbon production based on driving and flying courtesy of Conservation International
    •    For questions about this tool, contact Scott Maco (Davey Tree Expert Co.)

Here's some examples based on a 21" diameter Ash tree in a parkland setting

overallbenefitsFRPE21Park or other vacan

This 21 inch Ash provides overall benefits of:

$143 every year. 

While some functional benefits of trees are well documented, others are difficult to quantify (e.g., human social and communal health). Trees' specific geography, climate, and interactions with humans and infrastructure is highly variable and makes precise calculations that much more difficult. Given these complexities, the results presented here should be considered initial approximations—a general accounting of the benefits produced by urban street-side plantings. 

Benefits of trees do not account for the costs associated with trees' long-term care and maintenance. 

If this tree is cared for and grows to 26 inches, it will provide $147 in annual benefits.


Your 21 inch Ash will intercept 2,674 gallons of stormwater runoff this year.


Urban stormwater runoff (or "non-point source pollution") washes chemicals (oil, gasoline, salts, etc.) and litter from surfaces such as roadways and parking lots into streams, wetlands, rivers and oceans. The more impervious the surface (e.g., concrete, asphalt, rooftops), the more quickly pollutants are washed into our community waterways. Drinking water, aquatic life and the health of our entire ecosystem can be adversely effected by this process. 

Trees act as mini-reservoirs, controlling runoff at the source. Trees reduce runoff by:
    •    Intercepting and holding rain on leaves, branches and bark
    •    Increasing infiltration and storage of rainwater through the tree's root system
    •    Reducing soil erosion by slowing rainfall before it strikes the soil

For more information visit: The Center for Urban Forest Research


Your 21 inch Ash will conserve 208 Kilowatt hours of electricity for cooling and reduce consumption of oil or natural gas by 18 therm(s).


Trees modify climate and conserve energy use in three principal ways (see figure above):

    •    Shading reduces the amount of heat absorbed and stored by buildings.
    •    Evapotranspiration converts liquid water to water vapor and cools the air by using solar energy that would otherwise result in heating of the air.
    •    Tree canopies slow down winds thereby reducing the amount of heat lost from a home, especially where conductivity is high (e.g., glass windows).

Strategically placed trees can increase home energy efficiency. In summer, trees shading east and west walls keep buildings cooler. In winter, allowing the sun to strike the southern side of a building can warm interior spaces. If southern walls are shaded by dense evergreen trees there may be a resultant increase in winter heating costs. 

Located in front of a park or other vacant land, this 21 inch Ash will raise the property value by $73 this year.


Trees in front of single family homes have a greater property value benefit than those in front of multi-family homes, parks or commercial properties. Real estate agents have long known that trees can increase the "curb appeal" of properties thereby increasing sale prices. Research has verified this by showing that home buyers are willing to pay more for properties with ample versus few or no trees.

This model uses a tree’s Leaf Surface Area (LSA) to determine increases in property values. That’s a researcher’s way of saying that a home with more trees (and more LSA) tends to have a higher value than one with fewer trees (and lower LSA). The values shown are annual and accumulate incrementally over time because each tree typically adds more leaf surface area each growing season. The amount of that increase depends on the type of tree – some add more, some less. 

airqualityFRPE21Park or other vacant lan

Air quality benefits of your 21 inch Ash shown in the graph above. 


Air pollution is a serious health threat that causes asthma, coughing, headaches, respiratory and heart disease, and cancer. Over 150 million people live in areas where ozone levels violate federal air quality standards; more than 100 million people are impacted when dust and other particulate levels are considered “unhealthy.” We now know that the urban forest can mitigate the health effects of pollution by: 

    •    Absorbing pollutants like ozone, nitrogen dioxide and sulfur dioxide through leaves
    •    Intercepting particulate matter like dust, ash and smoke
    •    Releasing oxygen through photosynthesis
    •    Lowering air temperatures which reduces the production of ozone
    •    Reducing energy use and subsequent pollutant emissions from power plants

It should be noted that trees themselves emit biogenic volatile organic compounds (BVOCs) which can contribute to ground-level ozone production. This may negate the positive impact the tree has on ozone mitigation for some high emitting species (e.g. Willow Oak or Sweetgum). However, the sum total of the tree’s environmental benefits always trumps this negative.

For more information visit: The Center for Urban Forest Research

CO2BenefitsFRPE21Park or other vacant la

This year your 21 inch Ash tree will reduce atmospheric carbon by 874 lbs.


How significant is this number? Most car owners of an “average” car (mid-sized sedan) drive 12,000 miles generating about 11,000 pounds of CO2 every year. A flight from New York to Los Angeles adds 1,400 pounds of CO2 per passenger. Trees can have an impact by reducing atmospheric carbon in two primary ways (see figure at left): 

    •    They sequester ("lock up") CO2 in their roots, trunks, stems and leaves while they grow, and in wood products after they are harvested.
    •    Trees near buildings can reduce heating and air conditioning demands, thereby reducing emissions associated with power production.

Combating climate change will take a worldwide, multifaceted approach, but by planting a tree in a strategic location, driving fewer miles, or replacing business trips with conference calls, it’s easy to see how we can each reduce our individual carbon "footprints." 

For more information visit: The Center for Urban Forest Research

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