The gradual accumulation of partially decomposed leaf litter builds up into a thick layer of organic peat. Peat fires burn slowly, and can smolder on for several weeks. Fires are rare in the drier swamps, contrary to what you might think. Periodic floods in drier swamps wash away the leaf litter, and prevents the accumulation of a thick blanket of fuel. In the long run, fire helps maintain the cypress swamps, by preventing secondary succession towards a moist hardwood forest.
Wind is another important force of disturbance in the swamp.
Hurricanes and wind storms can cause a great deal of damage. It's much easier to topple a tree that is rooted only in mud. But mankind has become the biggest source of disturbance in the swamp. Most of our great southern swamps have been heavily logged at one time or another. The few remnants that have survived in places like Corkscrew Swamp, an Audubon sanctuary, show us how awesome these swamps must once have been.