Most trees, including the majority of deciduous and flowering trees, grow best in well-draining soil. Some have roots that can handle long periods of standing water or boggy conditions without damage, including willow trees. Only a few types of trees can thrive while growing in water. These kinds of trees, called swamp trees, are usually found in the cold- and warm-water marshes and swamps of the United States.
Mangrove trees are one of the few trees that grow and thrive even when its roots are continually submerged in salt water. There are three dominant species of mangrove trees in the United States, all of which are found in Florida. Worldwide, there are over 50 different types of mangrove trees. Mangrove trees are extremely beneficial to the coastal environment. They provide a home for marine organisms and birds, and help prevent coastal erosion.
The pumpkin ash tree (Fraxinus profunda) is a species of ash that thrives in standing water. It is called a pumpkin ash because the bottom of the trunk swells when growing in water, therefore forming a shape similar to that of a pumpkin. The tree is found in swamps and along the rivers of the Atlantic coastal plain. A tall, fast-growing tree, the pumpkin ash easily reaches heights of 130 feet.
The tupelo tree is found in swamps and areas where standing water occurs for much of the year. It withstands flooded conditions easily, and provides food and a habitat for birds and other wildlife, including raccoons. The tree grows in the swamps of the Deep South, but also in wet, boggy areas farther North. The average height of the tupelo tree is 50 feet tall. Like the pumpkin ash, the base of the tree often swells where it enters the water.
When most people think of the swamps of the Deep South, they picture bald cypress trees. These large trees, which are frequently draped with moss, feature long, slender needles and can live up to 600 years old. The bald cypress is well-known for its trunk, which develops "knees" at the base. The knees are extensions of the roots, which protrude in knob-like shapes above the water. The trees are called "pneumatophores," and are thought to help the roots obtain oxygen from the air when the area around the tree is flooded. Bald cypress trees grow in both standing and flowing water, and like the tupelo, they are an important source of food and shelter for wildlife.