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Ancient ecosystems bring to us a sense of posterity and a reminder of the balance of natural forces over time. Many forests, such as longleaf pine savannas, play important roles in the natural processes for clean air and water upon which humans depend. Because our natural forests have suffered destruction over the past century, many people have an increased awareness of this dramatic loss. Consequently, natural resource conservationists are trying to become better stewards to protect remaining fragments of these unique forests. In many cases, however, preservation efforts are no longer possible and restoration of badly degraded longleaf pine habitats, or sandhills, is necessary. Numerous restoration techniques are now being tested for use in these ecosystems.
The longleaf pine ecosystem once occupied a major part of the southeastern United States, including peninsular Florida. It has now been reduced to about 10 percent of its original coverage. This unique forest ecosystem is known for its dominant stands of longleaf pine ( Pinus palustris ) and pineland threeawn ( Arisida stricta ), with scattered turkey oak ( Quercus laevis ) and bluejack oak ( Quercus incana ). These forests are adapted to fire, a fact demonstrated by the thick, fire-insulating bark of pine and mature oak trees. Many herbaceous species, such as pineland threeawn, are stimulated by fire in the growing season to produce viable seed. In natural longleaf pine forests, intervals between burns were 3-4 years. When fire is suppressed, longleaf pine sandhills will succeed to mesic hardwood forests. Although the specific types of hardwood forests that invade are determined by the seed supply, all of these forests are characterized by higher shading, greater litter accumulation and less herbaceous ground cover than are present in longleaf pine forests.
Many vertebrate species are dependent on the longleaf pine community that dominates Florida's xeric sandhills. These include the federally endangered red-cockaded woodpecker ( Picoides borealis ) and the state-endangered Florida mouse ( Podomys floridanus ). Other animals in danger are the gopher tortoise ( Gopherus polyphemus ) and Sherman's fox squirrel ( Sciurus niger shermanii ), both of which are Florida-listed "species of special concern." These animals are important to the longleaf pine ecosystem because they serve important ecological functions such as seed dispersal and nest cavity construction. The gopher tortoise is considered a "keystone species" because its burrows provide refuge to many other species of vertebrates and invertebrates which, in turn, serve other important roles in the sandhills.
The major reason the animals of the longleaf sandhill ecosystem are in peril is that their habitat over much of the state has been destroyed or degraded through mismanagement. One method forest managers are using to restore or rehabilitate the longleaf pine ecosystem is reintroduction of summer fires to the sandhills of Florida. However, fire is a successful restoration tool only when sufficient ground cover of grass and pine needles is present as a fuel source. In stands that have been excluded from fire for 15-30 years, lack of ground fuel greatly restricts fire's intensity and its ability to spread. Consequently, new methods for restoration must be introduced.
Forest herbicides such as hexazinone have been used to suppress the growth of midstory oaks while encouraging the understory growth of pineland threeawn and longleaf seedlings. Before large-scale use of hexazinone occurs, however, a thorough evaluation of this herbicide's full impact on longleaf recovery, oak suppression and overall ecosystem functioning should be documented. Careful study of hexazinone's effects will provide a better understanding of how to restore and manage these natural forest systems in the future.