Home Preface Synopsis History of the Study Regional System Ecosystems - 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 References Appendices PDF version

Cypress forests occupy about 2,075 km² (800 mi²) chiefly in the Big Cypress Swamp (fig. 13) and smaller areas along the eastern edge of the northern Everglades and in the southern Everglades.

In the Big Cypress Swamp area, forests include open areas of small cypress trees and a scattered sparse growth of herbaceous plants, such as sawgrass or beakrushes, growing on a thin layer of marl soil or sand over limestone. Cypress domes and strands of larger trees grow over much of the forest. Domes are circular or egg-shaped features that are dome shaped in profile on the horizon. Strands are elongate areas of large trees that follow depressions. Shrubs and small swamp trees such as wax myrtle, coco plum, and pond-apple are common understory species within the domes and strands.

A cypress dome in the Big Cypress Swamp. [larger image]

Cypress domes occur where bedrock surfaces are low. The largest trees are near the center of the dome where bedrock is lowest and organic soils and water are deepest. Trees decrease in size toward the periphery. Vernon (1947) suggested that the large trees were oldest and that domes were explained by a gradual rise in water related to sea-level rise, which allowed cypress to spread progressively out from the center of the dome. According to Craighead (1971), the change in tree size probably reflects growth rate rather than age, and trees in deep nutrient-rich organic soil grew faster than those on the thin infertile soil.

Large cypress trees were present in the strands in the early 1900's, but logging has since removed most of them. However, one major area of large virgin cypress remains at Corkscrew Swamp where the National Audubon Society maintains a sanctuary. Some trees there tower 39 m (130 ft) and have a girth of 7.5 m (25 ft).

FIGURE 13. The Big Cypress Swamp watershed. [larger image]

Cypress requires abundant moisture for 1 to 3 months after seedfall for germination. Water facilitates germination by allowing the hard seedcoats to swell and soften. Seeds covered by water as long as 30 months may germinate if the water recedes. After germination, the seedlings require dry conditions for a time, and to survive they must grow high enough to stay above the seasonal floods of the next rainy season. Once established, larger trees can grow in the absence of seasonal inundation. Lowered water levels, however, make cypress susceptible to fire.