Measuring a tree’s carbon footprint
More and more people are aware of their daily carbon footprint. Humans have calculated the carbon footprint of train travel, transatlantic jets, TVs, washing machines, presidential campaigns and more. But what is the carbon footprint of a newly planted tree?
Planting a tree is largely regarded as an environmentally friendly act. But when it comes to absorbing and emitting CO2, some landscaping trees are friendlier than others. Now, thanks to researchers at the American Society for Horticultural Science, we know the carbon footprint of the flowering Forest Pansy, or redbud tree.
As part of a new study on the positive economic and environmental benefits of landscaped trees, researchers Charles R. Hall and Dewayne Ingram demonstrated how the carbon and economic footprints of a variety of plants can be calculated -- so everyone from farmers to backyard gardeners to urban planners can make more intelligent purchasing and planting decisions.
Expressed in units of tons (or kilograms) of carbon dioxide equivalents (CO2e), a tree’s carbon footprint is the measure of all greenhouse gases emitted during its life cycle -- that means its planting and care at its original nursery or farm, its transportation from birthplace to new home, and its maturing days lived out in yard, park, garden or forest.
“Knowing the carbon footprint of production and distribution components of field-grown trees will help nursery managers understand the environmental costs associated with their respective systems and evaluate potential system modifications to reduce greenhouse gas emissions,” explained Ingram and Hall. The researchers also monetized the different costs involved in raising and planting trees, including labor, equipment and transportation.                     
The economic cost of the redbud’s lifecycle was calculated at roughly $98, and its carbon footprint was measured at negative 63 kg CO2e. “Our findings validate those of previous studies that found that input costs of production processes (machinery, water, fertilizers, pesticides, and energy) are a significant portion of the nursery variable operation costs,” the authors wrote. “Thus, a more efficient use of these environmentally sensitive inputs cannot only reduce production costs for the nursery, but reduce their environmental risks or impacts as well.”