Tree planting is elementary.

A group of 3rd, 4th and 5th graders, bothered by a lack of trees behind their school, mastered GIS software to prove the value of increasing tree cover adjacent to busy Interstate 10 in San Antonio, Texas.

The students, members of a 4-H after-school program at San Antonio's Dellview Elementary School, were troubled by the noise, air pollution, and lack of shade trees on their playground. Working with Tom Fawcett, a 4-H volunteer leader, they learned how trees can ameliorate these problems and improve their learning environment.

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The students used CITYgreen software, developed by AMERICAN FORESTS, to model the benefits of adding five red oak trees adjacent to I-10 and two cedar elms on the playground. But first they enlisted the help of David Vaughan, an arborist from Etter Tree Care, to teach them the role trees play in the ecosystem and how to properly inventory the 58 trees on the school grounds.

Students collected data about each tree's diameter, canopy width, height, health, and growing conditions. Global Positioning System receivers recorded each tree's location so the data and locations could be imported into the Geographic Information System (GIS) program in their computers.

Back in the classroom, 4-H leader Fawcett worked with the students one-on-one, teaching them how to use ESRI's ArcView 3.3 GIS software and the CITYgreen extension to determine the benefits of their trees. Some students excelled in using the software and were responsible for digitally tracing impervious landcover features from an aerial photo base map. Other students created a canopy data file that included the 58 trees and all their field-collected attributes.

With digital data in hand, students input information into CITYgreen to analyze the school's landcover. The resulting report details the trees' ecological and economic value: They remove 105 pounds of air pollutants every year and store 54 tons of carbon. Planting five more red oaks in the area next to US 1-10 and two cedar elms on the playground, they found, would remove an extra pound of air pollutants annually.

Students then modeled the growth of all the trees on the school campus over a period of 25 years. The resulting additional tree canopy upped the amount of air pollutants removed each year by 53 pounds and increased the amount of carbon stored in biomass by 27 tons. Comparing the numbers, the students learned that the actions they take today by planting additional trees on their campus will have lasting environmental benefits long into the future.

The students presented their findings in a computerized presentation to fellow students, teachers, parents, and school administrators on Dellview's GIS day. The students explained that upping tree canopy at the school would not only better shade the playground, it would have a lasting impact on the health of the community by reducing air pollution and storing atmospheric carbon. Although the five red oaks and two cedar elms have not been planted due to lack of funding, these motivated students now have the knowledge and tools to push decisionmakers to consider effective planning practices for Dellview.