The region that is North Georgia today was explored a long time ago. As early as the 1540s, Spanish explorers trekked through the Cartersville area looking for gold. None was found there, but we have a golden treasure that’s well worth preserving: our native trees.
Subdivisions are growing, and too often developers remove native species and plant fast-growing exotic ones. This is wrong on several levels. The settlers who populated the northern part of the state in earnest, some years before the American Revolution, didn’t find grasslands interspersed with a few trees of Asian and European origin. This isn’t a prairie region.
Dense forests of oak, maple, pine and many other species were covering the hills and mountains. The tree leaves, and litter accumulating on the ground, provided food for insects. Those, in turn, met the nutritional needs of Georgia’s birds.
Somehow, the perception has evolved that insects are bad for the landscape, and chemicals are used widely to battle the six-legged creatures, their caterpillars and their competition of the arachnid world, the spiders. But if you want to see and hear birds in your landscape, you have to provide a food chain for them. Caterpillars eat leaves; birds don’t. To attract the birds, we need the caterpillars.
Leaf-eating insects that aren’t an invasive species from another continent won’t damage the trees. But they also can’t feed on the leaves of exotic trees, like the landscaping plants from Asia that are so frequently used in new subdivisions.
The chemical makeup of trees is finely tuned to their native environment, rejecting insects that “don’t belong.” As a result, our native crawlers don’t find much food in exotic landscaping, which amazingly is advertised as “diverse” and “beautiful.” Replacing insects and birds with chemical treatments isn’t a sustainable means of landscaping.
Doug Tallamy, an outspoken advocate of using native species to populate the urban and suburban landscape, points out that “biodiversity is not optional.” Such diversity must be accomplished with plants that developed in our region, because introduction of foreign species severely disrupts the natural food chain.
A good example for introduction of an exotic species gone wrong is the Chinese Tree of Heaven (ailanthus altissima), brought to the U.S. in the 18th century. Popular at first, it soon became a pesky invader and displaced native species. In Massachusetts, its weedy characteristics led to a statewide ban on its importation, sale and distribution.
Rudi Kiefer, Ph.D., is a professor of physical science and director of sustainability at Brenau University.