Environmental Information Series
The Right Mix of Trees

As part of a research project, students and faculty at SUNY ESF have determined the precise combination of trees that would be most effective in reducing the level of greenhouse gases in the air around Syracuse. The tree combination could reduce carbon dioxide by fifty-seven-percent by the year 2046, the team estimates. While the initial recommendations are just for Syracuse, New York, the project members’ methods would apply across the U.S.

During photosynthesis, trees remove carbon from the atmosphere and store it away in the tree’s wood. The process is known as sequestration, and it reduces levels of carbon dioxide in the air. Trees also provide shade and lower air temperatures, reducing the amount of energy that buildings use and, therefore, the amount of work required – and carbon dioxide released – by power plants. Trees with denser wood, such as hawthorn trees, are most effective at removing carbon dioxide from the air. Other trees emit volatile organic compounds, which contribute to the formation of ozone. Ozone in the upper levels of Earth’s atmosphere can have a protective effect, but particles of ozone in the air we breathe are considered pollutants.

To create the ideal combination of trees for Syracuse, the group chose trees with the best carbon-sequestering ability and lowest emissions of volatile organic compounds. Large and long-lived trees are crucial, particularly for the shade they provide. The team also recognized that it was necessary to include a lot of different types of trees, and avoid trees that are very susceptible to disease, such as the American Elm. Based on these criteria, the group suggested that the optimal vegetation for Syracuse would be a combination of 31 different types of trees, including dogwood, red hickory and hawthorn. Furthermore, the trees would be most valuable if they were planted in the center of the city, where areas of continuous asphalt typically send CO2 straight into the atmosphere.