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Forestry

The Urban Forest

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​​​RedOak_WursterPark.JPGThe urban and community forest is a defining and valued characteristic of the city of Ann Arbor, which residents affectionately call “​Tree Town,” helping make it a desirable place to live, work and play. It is made up of the trees, shrubs and woody vegetation growing along city streets; in public parks; and on institutional and private property. The urban and community forest provides many environmental, economic and social benefits to the community, including reducing stormwater runoff , improving water and air quality, ​moderating summer temperatures, lowering utility costs, improving quality of life and beautifying the cit​y. It is estimated that Ann Arbor’s city-managed urban and community forest, which includes trees growing along streets and in mowed areas of parks, provides nearly $4.6 million in benefits each year. ​

Learn more in the Urban and Community Forest Management plan​ (PDF). 

Tree inventory

Ann Arbor takes advantage of an online mapping tool that allows staff and residents alike to see the location and species of each city maintained tree within the City of Ann Arbor. Users can see this map on ​any computer or mobile device with internet access. ​

Cool calculator

Estimate the benefits of trees around your home using the National Tree Benefit Calculator -- type in your zip code, tree species and tree diameter. ​

iTree Eco analysis

In 2012, the city partnered with Davey Resource Group and the Michigan Department of Natural Resources with funding from the USDA Forest Service Urban and Community Forestry program to conduct an i-Tree Eco Analysis in Ann Arbor. The iTree Eco Analysis(1.45MB PDF) calculated the benefits that Ann Arbor's urban forest, both public and private trees, provides to the City. The analysis estimates that Ann Arbor has over 1.45 million trees; these trees remove 405/tons of pollution per year which is equivalent to the pollution produced by 358,000 automobiles annually.  

How much does the community benefit from one​ tree?

To demonstrate the value trees provide to our community, consider the benefits generated by a typical tree in Ann Arbor. A 16-inch diameter sugar maple planted on a single family residential lot provides $149 in benefits every year (National Tree Benefit Calculator).

 Lower energy costs

Value of one tree: $63.64

Value of all Ann Arbor Public Trees: $2,252,055

An individual sugar maple tree conserves 98 kilowatt-hours of electricity for cooling and reduces consumption of natural gas by 35 therms. Trees modify and conserve building energy use in three principle ways:

  • ​​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.

Higher property values

Value of one tree: $57.95

Value of all Ann Arbor Public Trees: $1,368,302

Research shows homebuyers will pay more for a property with mature trees than for a property with few or no trees. This analysis is based on the tree's leaf surface area, and the property value benefit will increase as the tree grows. 

Cleaner water​

Value of one tree: $14.10

Value of all Ann Arbor Public Trees: $519,895

Stormwater run-off is the most prevalent water quality problem in the nation. One sugar maple tree can intercept 1763 gallons of stormwater run-off each year. Together, Ann Arbor's public trees intercept 65 million gallons of stormwater. Trees in the urban environment decrease the quantity of stormwater run-off and improve the quality of run-off that eventually reaches local lakes, streams, and reservoirs.

  • The urban forest canopy, along with tree branches, bark, and mosses, captures and stores precipitation, delaying the onset of peak flows and reducing the total amount of run-off that reaches urban waterways via the storm drain system.

  • Trees slow down stormwater run-off and promote groundwater infiltration.

  • Trees take up water through their root systems and release it to the atmosphere through evapotranspiration, facilitating greater water storage potential in soils and increasing the amount of time before rainfall becomes run-off.

  • Tree roots take up nutrients and potentially harmful chemicals from stormwater​ run-off. Pollutants are filtered out as water moves through the ground.

Healthier air

Value of one tree: $11.53

Value of all Ann Arbor Public Trees: $477,402​

Air pollution is a serious health threat that causes asthma, coughing, headaches, respiratory and heart disease, and cancer. The urban forest mitigates 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, reducing the production of ozone

  • Reducing energy use and subsequent pollutant emissions from power plants

Reduced carbon dioxide levels

Value of one tree: $1.39

Value of all Ann Arbor Public Trees: $52,450

One sugar maple reduces atmospheric carbon dioxide (CO2) levels by 502 pounds per year. Collectively, Ann Arbor’s public tree resource reduces CO2 by 7,851 tones per year.

 
  • Trees sequester, or lock up, carbon in roots, trunks, branches, and leaves while growing, and in wood products after harvest.

  • Trees near buildings can reduce heating and air conditioning demands, thereby reducing emissions associated with power production.​​

​Forestry Public Works
Wheeler Service Center
4251 Stone School Road
734.794.6320
customerservice@a2gov.org