The only noticeable slopes are sharp terrace scarps and natural levees that rise sharply to several meters above adjacent bottom lands or stream channels. Swamps are significant in the extreme southern part of Louisiana. Virgin bald cypress growing in grassy lake in Arkansas.
Rain falls throughout the year, with a minumum in autumn.
Temperature and precipitation decrease as one moves northward. Snowfall is negligible. Pecan is also present, associated with eastern sycamore, American elm, and roughleaf dogwood. Vines are prolific along water courses.