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Hardwood hammocks are areas of dense vegetation including hardwood trees and shrubs, palms, ferns, and epiphytes. They are widely distributed and grow in most terrains where conditions of favorable land elevation and fire protection occur. Hammocks grow on land slightly higher than that of surrounding marshes, wet prairies, cypress forests, or mangrove forests and in open country where they stand out on the horizon as tree islands. Tropical hammock forests are among the most diverse systems in south Florida, containing more than 100 species of trees and shrubs. The animals of hardwood hammocks are represented by many of the pine-forest species.

In the northern part of the region, temperate-zone trees, such as red maple and laurel oak, predominate in the lower hammock forest areas, and live oak and cabbage palm predominate in higher areas. To the south, broad-leaved tropical trees and shrubs, such as strangler fig, wild tamarind, pigeon plum, gumbo limbo, poisonwood, redbay, and coco plum. become dominant on numerous small tree islands in the Everglades, in pine forests, or as hammocks along Florida Bay or on the higher Keys. Many tree islands of relatively low, elevation, particularly in the Everglades, have swamp hardwood trees.

Hardwood hammocks grow on higher land that is seldom flooded and is protected from fire. [larger image]

Hammock forests represent a climax community developed in the absence of fire. Areas surrounded by deep water or areas of dense vegetation that retain high humidity and soil moisture are protected from fire and thus may favor the growth of these forests. Hammocks develop slowly as organic material accumulates and builds up the land. The general sequence is shown in figure 8.

Temperature and water salinity, in addition to fire, influence hammock development and diversity. Frost restricts some tropical species, and coastal spray or tidal flooding, especially during storms, inhibit species near the sea.

Because hammocks are on higher land, they have long been sites of human occupation. Most large hammocks in the Everglades show signs of habitation such as old pottery, metal containers, or planted citrus trees. Indians lived on and farmed these hammocks originally; later they were used by white settlers and hunters. Large areas of hammock forest along the Caloosahatchee River, along the Atlantic Coastal Ridge, and on Key Largo have been destroyed fairly recently by agricultural and urban development. Hammocks have also been affected both by lowered water levels, which increase the chance of severe fires but which also favor hammock growth in areas formerly flooded, and by exotic species which have invaded some areas.