CARBON EATERS AMONG US
During photosynthesis, growing plants and trees remove carbon dioxide (CO2) from the atmosphere. They store it in the form of cellulose in their leaves, trunks and roots, then release oxygen to the atmosphere. Trees trap or sequester much more carbon than plants, since they are bigger and live longer. In this way, trees combat global warming/climate change because they store CO2 emitted by autos and power plants before it can otherwise reach the upper atmosphere. Once there, it traps heat released from around the Earth. It is estimated that each person in the U.S. generates roughly 2.3 tons of CO2 annually. A large front-yard tree of 9 to 20 inches of diameter can sequester 19 to 43 pounds of carbon per year from the atmosphere. During a 40-year period, the U.S. Forest Service estimated that all the U.S. Forests combined sequestered enough carbon each year to offset approximately 25 precent of the nation’s carbon generated by humans.

There is much interest in identifying which trees are the most efficient in trapping CO2. Surprisingly, the “best” tree for carbon capture and storage is the Silver Maple (Acer saccharinum). Research at UC Davis suggests that one such tree can trap almost 25,000 pounds of CO2 after 55 years, 25 times more than a cherry or plum tree. The Silver Maple has been denigrated at times because of its brittle branches, shattering in storms, a tendency to clog nearby water and drainage lines and its prolific seed production. Other carbon-eater champions are the horse chestnut, black walnut, American sweetgum, white pine, Douglas fir, scarlet and red oaks, and bald cypress. By 2009, the United Nations Billion Tree Campaign had planted more than 7.4 billion trees in 170 countries to combat climate change.

To maximize climate benefits for your own property:

• plant native species adapted to your local growing conditions,
• plant a tree which will mature to a large size, while avoiding planting near power lines and underground pipes,
• choose a long-lived species that matures slowly,
• over time, plant a diverse variety of trees, least likely to be eliminated by disease,
• plant trees to block winter winds and to provide summer shade.

Frank Thorp, Tree Body member.
Adapted from an article by Janet Marinelli, National Wildlife Foundation magazine Colorado Tree Coalition.