Wednesday, September 3, 2003

Georgia's ever-changing forests

The perfect forest, in most people's minds, is open woodlands with towering trees hundreds of years old. These are the forests we want to save when we think of forest conservation. Beginning with a few plants, forests go through a process of "succession" ideally arriving in a climax or old growth condition. Disturbances such as fires, tornadoes or diseases interrupt succession and creating totally different situations from the "perfect" forest. In reality, all forests are in a constant state of continual disturbance. Succession may progress toward the climax forest, but true climax is seldom, if ever reached. The forests the first settlers saw were probably more disturbed than stable. The same natural disturbances are present today; some are obvious, while others are less apparent.

The impact of flooding can be minimal or do major damage. The effects can range from total destruction setting the forest back to early stages of succession, to minor changes in species composition. Drought directly affects trees by weakening or killing some species and releasing others. Periods of drought alone would maintain some dry woodland situation, but usually predisposes a forest community to fire.

Wind, occasionally in the form of tornadoes or severe thunderstorms, knock down trees, returning a site to an early successional stage. The removal of larger trees in a forest releases the understory speeding up or slowing down secession. Wind also disperses seeds over long distances, and when added to the creation of open space can greatly change the species composition of a forest. Animals can influence the species makeup of a forest. Large grazing and browsing animals have a more serious direct impact, while smaller mammals do not. Insects and diseases can have an even more devastating impact, from killing just a few trees to wiping out entire forests.

Natural fires (lightning) usually account for about one percent of all fires in Georgia. Low intensity, repeated fires create and maintain a thin canopy of fire resistant trees and fire tolerant vegetation, resulting in a savanna or woodland situation. Less frequent fires are more intense and have a regenerating effect on a forest. Without fires to reduce fuel buildups, fires burn hot and can kill trees. Severe fires can destroy ground litter and humus and set a forest back to early succession stages.

Human disturbances are thought to have a more serious and long lasting effect. Cutting, burning, land clearing, pollution and erosion are more frequent and severe. They are outside the range of tolerance of the natural forest and change the forest forever. Becoming educated on wise land use practices will reduce detriment to the environment, enhancing forests and wildlife habitat.

Forests in Georgia will rarely, if ever reach a climax state. They are perpetually disturbed in one way or another, always moving ahead from one succession type to another, briefly reaching near climax conditions, only to be disturbed once again either by nature or by man, resulting in ever changing forests.

You can have a positive impact on your woodlands by implementing wise forest management practices. Contact your local office of the Georgia Forestry Commission for more information or assistance at 770-227-5522 or 770-358-1459. Visit www.gfc.state.ga.us.

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