Some 2,500 years ago the river began building a delta in the area that is now New Orleans. Within each delta, the river may occupy several different channels. This delta had at least three main channels, and one of them, Bayou des Families, deposited the sediments that underlay the present-day preserve. Ecology Plant Life . In the delta, a combination of soil-type, elevation, moisture, and salinity control what plants grow where.
Hardwood forests grow on the elevated land of the natural levee.
Here, majestic Live Oaks take advantage of the dry ground. On the back-slope of the levee, the forest changes to one dominated by an understory of palmetto. Swamp covers the lowest portion of the natural levee, where water stands for much of the year. This forested wetland is home to the stately Baldcypress. Beyond the swamp lies the flat treeless marsh, the eastern end of one of the largest expanses of floating freshwater marsh in the world.