Up Front | Findings

June 1999: Vol. 78, No. 3

Acid rain drains soil's nutrients

Markewitz found that, among its mulitude of sins, acid rain also robs the soil of nutrients and threatens future forest productivity.

In addition to damaging paint on cars, corroding marble statues, and destroying fabrics, acid rain also depletes the soil of important nutrients, thereby posing a threat to future forest productivity. This information is part of a new study conducted by forestry professor Daniel Markewitz.

Acid rain is created when vehicle and other man-made emissions are released into the atmosphere. Converted into acids and dissolved in water, Markewitz says they deplete the soil of calcium and magnesium, nutrients trees need to grow.

Nutrient depletion could affect sites that are intensively managed, such as pine plantations, where trees are grown and then cut for industry use.

"Since there's an acceleration of calcium depletion, instead of taking three or four rotations to use the calcium pool, it might take one or two," says Markewitz, whose findings were published in the October 1998 issue of the Soil Science Society of America Journal. "We'll need to think about inputting calcium sooner than if there was no acid rain."

Acid rain can't be blamed for all of the nutrients draining out of the soil, Markewitz says, because nutrient depletion is natural in some cases. Trees respire like humans, and the carbon dioxide molecules they release become acids that also deplete the soil of nutrients. However, Markewitz's study found that nearly 40 percent of the increasing acidity can be attributed to acid rain.

"I'm not crying wolf just yet," Markewitz says. "But we should all be good stewards of the environment and try to drive our cars a little less."

—Stacie Sutton

Even scientists call it Hotlanta

Atlanta is an island unto itself—an "urban heat island"—where temperatures can run up to 10 degrees higher than in surrounding areas, giving the city its own weather patterns and causing thunderstorms.

That's the conclusion of a new NASA-sponsored study by the Atlanta Land-use Analysis: Temperature and Air-quality (ATLANTA) project, which enlisted help from researchers at several universities, including UGA, Utah State, San Jose State, and Colorado State.

Materials used in roads and roofs create the problem by absorbing heat during the day and holding it long after the sun sets. And a 10-degree rise in temperature doubles the chemical reaction that produces ozone—and, hence, smog.

Using aerial photos and satellite data to study Atlanta's growth, geography professor C. P. Lo and grad student Xiaojun Yang found that from 1973-98, nearly 350,000 acres of forest area were cleared in 13 metro counties. Since 1973, developed suburbs have doubled to nearly 670,000 acres. Commercial development also doubled. Expanding population and loss of vegetated land lead to more roofs and roads—and, thus, to a larger urban heat island.

WITH ATLANTA'S POPULATION AT FULL GALLOP, GROWTH IS THE KEY TO UGA'S STRATEGIC PLANNING
With four metro Atlanta counties among the nation's top 10 fastest-growing counties—including Forsyth at No. 1—a UGA demographer recommends that UGA keep a close eye on the state's growth as it formulates a strategic plan for the next decade. "Sixty percent of the growth in Georgia is from new people moving into the state," says Doug Bachtel, who notes that migrants tend to be younger and have higher income and education levels—which increases the pool of college-bound students. In the 1980s, 43 percent of the state's population had no high school degree. That figure dropped to 29 percent in the 1990s and should be even lower in the next decade, says Bachtel, noting that there's still room for improvement.

"The presence of forest has a large modification effect," says Lo. "We can't tell exactly where it begins or how much it changes the local climate. What we can say is that there is a huge increase in urban heat, making Atlanta an island."

—Phil Williams

Out-of-field teaching a national problem

It's no secret that out-of-field teaching—when teachers are assigned to subjects in which they have little education or training—has become a national problem. A recent survey reports that one-third of all secondary school math teachers, one-fourth of English teachers, and more than half of physical science and secondary school history teachers have neither a major or a minor in the subject they teach.

But the reasons for the spread of out-of-field teaching have been diagnosed incorrectly, says UGA sociologist Richard Ingersoll, whose article analyzing out-of-field teaching was recently published in Educational Researcher.

In the past, says Ingersoll, reformers have pushed for tougher teacher-certification standards, more rigorous academic course work, and testing of teaching candidates as an antidote. Many new programs designed to entice professionals into a mid-career change to teaching have been implemented. And President Clinton has even proposed a major initiative to recruit and train new teachers to serve in low-income schools.

But the real issue is more fundamental and may begin with how the teaching profession is perceived in the U.S.

"Unlike many European and Asian nations," says Ingersoll, "in this country elementary and secondary school teaching is largely treated as lower-status work and teachers as semi-skilled workers."

As a result, he says, teaching is plagued by problems of both recruitment and retention that have made out-of-field teaching a common practice in American schools. As Ingersoll (a former high school teacher himself) points out, high-quality teaching requires expertise and skill, and teachers should not be treated like interchangeable blocks that can be placed in any empty slot, regardless of training.

The solution may lie in the way schools are managed, and in the continuing treatment of teaching as semi-skilled labor. Reforms that ignore this problem will simply not work, says Ingersoll, and, in fact, may do more harm than good.

Ingersoll says schools should offer incentives or provide retraining to attract and retain teachers. Second, principals should cut back on out-of-field assignments for beginning teachers to help cut down on the large exit of such teachers from the profession. But the long-term way to upgrade the quality of teachers, he says, is to upgrade the quality of the teaching job itself.

"Few would require cardiologists to deliver babies, real estate lawyers to defend criminal cases, or sociology professors to teach English," says Ingersoll. "And if we treated teaching as a highly valued profession, there would be no problem attracting and retaining more than enough excellent teachers."

—Phil Williams