734.794.6320Replacement Value
Ann Arbor's inventoried trees: 51,806
Estimated replacement value of Ann Arbor's inventoried trees: $92 Million
The urban forest provides many benefits. Sustained planting and maintenance efforts have led to an increase in the number of large trees (those reaching maturity) and small trees representing newly planted trees. Some of the benefits provided by these trees are detailed below.
Cleaner water
5.7 million gallons of annual rainfall intercepted
Annual Value of all Ann Arbor Public Trees: $52,487
Stormwater run-off is the most prevalent water quality problem in the nation. 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
24,000 pounds of annual air pollutants removed
Value of all Ann Arbor Public Trees: $89,706
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
862,000 pounds of annual CO2 sequestered
Value of all Ann Arbor Public Trees: $74,884
Carbon capture is the process of capturing carbon dioxide formed during power generation and industrial processes.
Carbon storage
65,832,000 pounds of CO2 stored
Value of all Ann Arbor Public Trees: $5,613,781
Trees sequester, or lock up, carbon in roots, trunks, branches, and leaves while growing, and in wood products after harvest so that it is not emitted into the atmosphere.
Lower energy costs
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
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.
