1920] Dozier: Insects of Florida 337' 



ECOLOGICAL SUCCESSION. 



All recent geological formations when first elevated above- 

 sea-level consist of sand dunes and hills, with swampy depres- 

 sions or even lakes between them. A little east of Gainesville 

 in what Harper ('15) calls the East Florida Flatwoods belt, we 

 get a plant association that he calls scrub. This is the first 

 association to take possession of the low hills. 



There are two distinct ways in which hammocks originate. 

 (1) Going from high pine land to hammock and (2) swamps and 

 lakes to hammock. 



Starting with High Pine Land we find it composed mostly 

 of long-leaf pine with grasses and a few saw-palmettoes on the 

 forest floor. There is very little shrubbery. After a little 

 humus has gotten into the soil the black-jack, turkey, post and 

 red oaks begin to come in.* This stage is known as Piney 

 Woods. 



Hickories and water oaks begin to come in and in dry 

 situations we get the live oaks. This is the beginning of the 

 Hammock. Now the oaks and hickories become more- 



numerous, sweet gum enters, and the shrubbery thickens. 

 In the last stage the magnolia becomes the dominant tree and 

 the shrubbery becomes, in many instances, an almost impen- 

 etrable jungle. 



Starting with the shallow lake, we have in the deeper water 

 pond lilies (floating all around in the water are the recently 

 introduced water hyacinthes). Coming near the shore we find 

 saw-grass, rushes, and a little willow; the buttonbush is typical 

 of such places. Cypress comes in, forming a cypress swamp. 

 Tupelo is nearly always mixed in with the cypress. As sand is 

 washed in and dead trees fill up the swamp, among the old 

 cypress and tupelo and in dry situations, the red maple comes in. 

 In turn follow the ash, water oaks, hornbeam, and sweet gums. 

 Finally, when everything is filled up and well-drained, the- 

 magnolia and hickories begin to come in, giving us the climax 

 magnolia-hickory-oak association. 



*It is reasonably certain that if fires were kept out of a long-leaf pine forest 

 long enough, hardwood trees of various kinds would come in and choke out the 

 pine (which does not thrive in shade), and thus gradually convert the pine forest 

 into a hammock. Hammock trees require humus and are sensitive to fire, and 

 consequently they cannot invade the pine land very fast as long as fires prevail. 



