May 1, 2007 A research team found 31 hardy trees that sequester carbon efficiently for the New York region, mitigating against the impacts of high deforestation and carbon release into the atmosphere in that area.
Global warming is a highly debated political issue these days. Many people wonder what one person can do to help. Planting trees can play a powerful role in cleaning up the local environment, but they're disappearing from cities across America.
Cities in the United States have lost more than 20 percent of their trees in 10 years. Richard Smardon, Ph.D., is an Environmental Planner at SUNY College of Environmental Science and Forestry in Syracuse, New York, attributes the disappearing trees to more construction around the country. Dr. Smardon says one huge benefit of trees is that they store so much carbon, which is good for the environment.
He explains, "The more carbon we store in the tree, the less goes into the atmosphere." Dr. Smardon and forester Allan Drew, Ph.D., have found the perfect mix of trees for Syracuse, New York, a combination that packs a hefty environmental punch. Dr. Drew says they are working on changing one city at a time. He told Ivanhoe, "We are making a conscious effort to produce communities that have better air quality and better health for the people that live there."
In a year-round venture, Dr. Smardon and Dr. Drew found 31 trees that are high performers in the region, like the sycamore. Their goal is to get people to protect and plant those trees in their neighborhoods, so everyone can make a change. Dr. Smardon says it's easy, "It's like using solar cells on your roof or driving a hybrid car. It's something the individual can do so they know they are making a difference."
Trees absorb and store greenhouse gases. A USDA study shows the trees in New York City alone remove 1,800 metric tons of air pollution from the local atmosphere. They provide shade, which also reduces how much energy we use.
The American Geophysical Union contributed to the information contained in the TV portion of this report.
BACKGROUND: As part of a research project, students and faculty members at the State University of New York's College of Environmental Science and Forestry have determined the precise combination of trees that would be most effective in reducing the level of greenhouse gases in the air around Syracuse, New York. If the combination of trees were planted it could reduce carbon dioxide -- a greenhouse gas -- by 2% by the year 2046, the team estimates. While the initial recommendations are just for New York, the project members can give recommendations for all across the United States.
HOW IT WORKS: During photosynthesis, trees remove carbon from the atmosphere and store it away in the tree's wood. This 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.
A WINNING COMBINATION: 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 SUNY group also recognized that it was necessary to include a lot of different types of trees, and avoided 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 group 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.
ABOUT PHOTOSYNTHESIS: Photosynthesis is the process of converting light energy to chemical energy and storing it in the bonds of sugar. This process occurs in plants and some plant-like algae. Plants need only light energy, carbon dioxide and water to make sugar. The light reaction converts light energy to chemical energy via chlorophyll, a green pigment, and several other pigments such as beta-carotene. Each differently-colored pigment can absorb a slightly different color of light and pass its energy to the central chlorophyll molecule to do photosynthesis. The energy harvested via the light reaction is stored by forming a chemical called ATP, a compound used by cells for energy storage. The dark reaction converts carbon dioxide to sugar. This reaction doesn't directly need light in order to occur, but it does need the products of the light reaction (including ATP).