Successional and Environmental Relationships of the Forest Vegetation of North Central Florida

The southern mixed hardwoods, mixed hardwood swamps, bayheads, sand pine scrub, sandhills, pine flatwoods, and cypress heads are the major forest community types in north central Florida. The first three are climax communities (on upland, wet fertile, and wet acid sites, respectively) the latter four are successional. With improvement of drainage or the elimination of fire, succession may proceed in a variety of directions. The sandhill and scrub community types occur on dry sterile soils and are fire-maintained. Succession proceeds toward the southern mixed hardwoods. The pine flatwoods are fire-maintained and are on poorly drained soils. With release from fire, succession proceeds toward either of the three climaxes. The direction appears related to soil moisture and fertility. Cypress heads are limited by flooding. With improved drainage they may be converted to mixed hardwood swamps or bayheads depending upon soil fertility. An environmental similarity index, based on 11 variables, was calculated for the six community types as well as for 45 tree species that occurred in five or more stands. Three general groups of species are recognized: (1) successional, (2) climax pioneer, and (3) climax exclusive. The successional and climax pioneer are habitat generalists in that their environmental similarity indices are lower than that of the community types. Floristic continuity in large-scale vegetation is maintained by the presence of the habitat generalists while the element of discontinuity may be attributed to the climax exclusives. The mean of 11 variables for 45 tree species was used to position the species spatially. The spatial relationships relate the six community types without aberrant transitions.