Cypress‐Gum Communities in the Blue Girth Swamp Near Selma, Alabama

Abstract

Cypress-gum forests are common along the seaward margin of the Coastal Plain from Texas to Virginia. In addition, there are numerous stands in the low backhands of many of the streams in the interior of the southeastern states (Coulter, '04). Throughout the broad alluvial valleys these swamp forests are usually composed of bald cypress (Taxodium distichum) 2 and tupelo gum (Nyssa aquatica), whereas in pineland ponds they include pond cypress (Taxodium ascendens) and swamp black gum (Nyssa biflora) as the predominant species. In the shallow swampy areas of the lower portion of the Gulf Coastal Plain, slash pine (Pinus caribaea) may be an important associate of pond cypress and swamp black gum. Each of these five swampland species has been observed in pure stand. In some areas these species may occur as companion species, especially where pineland streams flow into broad river valleys. The tupelo gum-cypress-swamp black gum and the tupelo gum-cypress forests investigated have been designated as variants of Cover Types Numbers 94 and 95 by the committee on forest types of the Society of American Foresters (Hawley, R. C. et al, '40). The following species have been listed as common associates: red maple (Rufacer drummondii), planer tree (Planera aquatica), pumpkin ash (Fraxinus profunda), water ash (Fraxinus caroliniana), and black gum (Nyssa sylvatica). These forests are of much importance economically since they yield timber crops on annually flooded soils in addition to harboring some of the most valuable and interesting animals indigenous to southern United States. The stands herein reported are located in the Blue Girth Swamp in Dallas County, Alabama. This swamp is approximately 5 miles east of Selma and is in communication with the Alabama River 4 miles southwest of where the swamp is crossed by State Highway Number 14. The swamp is accessible by numerous field roads, the Southern Railroad, and a cable suspension bridge. Each of these approaches lies to the north of State Highway Number 14 (fig. 1). Blue Girth Swamp lies in an elongated basin which is approximately 10 miles in length and averages about one-third of a mile in width. MiVost of the surrounding terrain is under cultivation, the major crops being cotton, corn, and peanuts. The swamp is spring-fed and possesses a nearly continuous hydroperiod. The average annual fluctuation during normal stream flow approximates 3 feet. Following excessive precipitation during April, 1938, the Alabama River experienced a rise of some 10 feet above flood stage with a corresponding rise in the water level of the swamp. Such a water level, however, is unusual in the Blue Girth Swamp. In the swamp, stands of the tupelo gum-cypress complex are characteristic of the deeper waters (2-7 ft.), while samples of the tupelo gum-cypressswamp black gum forest are found along the marginal areas in shallower waters (0-2 ft.). Pure forests of swamp black gum and marshes of bur-reed (Sparganium americanum) are present in the shallow waters south of State Highway Number 14. Contiguous stands of tupelo gum-cypress-swamp black gum, tu1 Contribution from the Botany Department, Tulane University, New Orleans, Louisiana. The authors wish to thank Mrs. Faith P. Mackaness for drawing the map of Blue Girth basin and environs. 2 Nomenclature follows Small's Manual of the Southeastern Flora, 1933.