"It takes, I think, nine trees to supply a lifetime's worth of oxygen for one person," she said, though she wasn't sure of her figures.
According to the Arbor Day Foundation, the U.S. Department of Agriculture says an acre of forest absorbs six tons of carbon dioxide and emits four tons of oxygen - enough to meet the annual needs of 18 people.
You don't have to be a modern "greenie" to be well-versed on the subject. An early tree advocate was J. Sterling Morton, a 19th-century journalist and naturalist who persuaded the Nebraska legislature to sponsor the first Arbor Day. On April 10, 1872, Nebraskans planted about a million trees, and by the middle 1880s, most of America was celebrating Arbor Day on the last Friday in April. (Harford County schedules its celebration to coincide with Good Friday, a school holiday.)
On Friday, the 137th anniversary of Morton's brainchild, the National Arbor Day Foundation in Nebraska again recognized Harford County as a "Tree City USA" - a municipality that spends at least $2 per citizen on tree initiatives while meeting a few other criteria. (Harford County, population 233,000, spent more than $920,000 this fiscal year.)
More than that, it gave aspiring Sterling Mortons a chance to get outside and take part in a project with no apparent downside.
Bethany and her friends Maggie Roszko, 9, and Rebecca Hudson, 10, were getting credit toward their Girl Scout Bronze Awards. Justin Jones, 19, of Aberdeen, and Joshua Ray, 17, of Baltimore, cadets from the Freestate Challenge Academy, a residential school for at-risk youth, were also getting community-service credit.
But some benefits were harder to quantify. Judy Schaeffer of Whiteford, a gardener by avocation, took a moment from her digging to look at the rows of new young seedlings.
"They'll grow up before you know it," she said. "It's beautiful. Who doesn't love a tree?"
