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Ecosystems of south Florida

Freshwater and terrestrial ecosystems

Mixed swamp forests

History of the Study
Regional System
- Freshwater
and Terrestrial

  -  System relations
  -  Effects of man
  -  Canals & lakes
  -  Ponds & sloughs
  -  Sawgrass marsh
  -  Wet prairies
  -  Pine forests
  -  Cypress forests
  >  Mixed swamp forests
  -  Bay heads
  -  Hardwood hammocks
  -  Palmetto & dry prairies
- Coastal
- Man-dominated
Hydrologic Systems
Final Word
PDF version
Mixed swamp forests are areas of dense stand of tree, shrubs, vines, ferns, and epiphytes that usually occur as elongated strands that follow low drainage areas. Elevation of land with in a forest is variable. Most of the forest, however, is seasonally flooded for months. The forest is usually a mix of shrubs and trees. Cabbage palm, red maple, wax myrtle, coco plum, sweetbay, and redbay are widely distributed. Cypress, willow, pop ash, and pond-apple tend to be more common in deeper water. Hammock vegetation, such as laurel oak, dahoon, wild coffee, myrsine, and occasionally live oak and pine, grow on the higher land. Although the forests are generally a mixture of trees, one species may predominate over a small area. Willow often dominates burned areas. Pop ash, pond-apple, or cypress are often predominant in deep water. Bay trees are sometimes dominant, especially on tree islands in parts of the Everglades; such islands are called bay heads. Cabbage palm predominates at the seaward end of some strands. Large cypress trees dominated much of the forest before logging.

The Fakahatchee Strand is the largest mixed swamp forest in the Big Cypress Swamp. The strand was logged in the late 1940's and early 1950's, and virtually all large cypress trees were removed. Maple, oak, willow, and other swamp hardwoods became dominant after the removal (Alexander and Crook, 1973).

The strand is still known for its rich and diverse flora, which includes at least 39 species of orchids, some of which are found nowhere else (Luer, 1964), 20 species of ferns, and 11 species of bromeliads (Finn, 1966). Numerous small lakes are distributed along the axis of the strand.

Trees and shrubs are the primary producers of the mixed swamp forest. Their production sustains the animals and microbes. The Fakahatchee Strand, an undrained swamp, produced twice the total biomass and four times the woody growth as a nearby, but recently drained, swamp. Stress on the drained swamp-forest system was indicated by a thinning of the canopy; leaf litterfall was 45 percent greater in the drained swamp than in the undrained swamp. Thinning of the canopy decreases productivity and increases sunlight penetration. Increased sunlight accelerates drying of leaf litter and makes the system vulnerable to fire damage (Carter and others, 1973).

Cycling of mineral nutrients on the swamp-forest floor is also controlled by moisture conditions. Moist conditions accelerate litter decomposition by at least a factor of 1.3, creating favorable conditions for macrodecomposers to further accelerate the process by 1.6 times. As a result, concentrations of mineral nutrients increase more rapidly in the litter of the Fakahatchee than in the drained strand (Carter and others, 1973).

photograph of a remaining stand of large cypress
aerial photograph of the Fakahatchee Strand
(left) A remaining stand of large cypress. [larger image] (right) An aerial view of the Fakahatchee Strand. Large royal palms rise above the forest canopy. [larger image]

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