Sand Pine (Pinus clausa)
The only real tree in Florida scrub, sand pine is uniquely adapted to live in a plant community that depends on periodic fire for its continued existence. The cones of sand pine remain on the tree and do not open until the tree actually burns to death. Only the heat of a killing fire can melt the wax that seals the cones, thus allowing the release of seeds to start a new generation. This way, seeds are not wasted as they would be if they fell in the shade of the parent tree. And, the species is able to repopulate the site quickly after a devastating fire. (In recent decades modern man has reduced the frequency of and even eliminated fire in many Florida scrubs. This has allowed the occasional sand pine "sport" that already happened to have cones that open without fire to reproduce successfully. In effect, man has selected for sand pines that release their seeds without fire, and today you can see trees with open cones in many scrubs.) Sometimes, if conditions are just right, sand pine seedlings survive in tremendous numbers and the species comes to dominate the site, creating a sand pine forest and shading out the scrub perennials and shrubs. But if it doesn't rain when the tiny sand pine seedlings are getting started, most will die and the survivors will be scattered in a true scrub with other scrub plants.
See also Floridata's profile of the sand pine (Pinus clausa)