Water Tupelo

Water tupelo, or tupelo gum, survives on swampy and poorly drained land, provided water recedes by the time the growing season begins and first-year height growth is above the growing season water level of the succeeding year. Under continuous inundation from winter on, seedlings and young saplings maintain dormancy into July and then proceed to grow normally. Because of butt swell, dbh measurements are meaningless: a stand of 200 ft.2 per acre above the butt swell would exceed 1000 ft.2 if measured at breast height. Butt swell "bottlenecks" increase with wetness of the site, tree size, and tree age.

Associated with water tupelo are baldcypress and swamp tupelo trees. In deeper swamps, swamp tupelo is absent, indicating that depth of water is a limiting factor in the distribution of the species. Swamp tupelo, but not water tupelo, occurs in the Okefenokee Swamp and in deep bogs of the Louisiana and Tennessee Delta. Species occurrence reflects the secondary distinctions within the Coastal Plain: muck swamps, small estuaries, and piney-woods tributary stream bottoms. In those locales, water tupelo, if present, inhabits the fresh, moving water sites along drainage courses and alluvial swamps. The two species meet along the margins of moving water swamps, in some minor stream bottoms on their respected preferred sites, and in the smallest estuaries. Standing water in water tupelo swamps is generally deeper, though of shorter duration, than in the swamp tupelo sites.

Figure 4.26 Quality hardwoods in a southern swamp. These tupelo gum trees, like many other broadleaf species growing in wet sites, developed buttressed bases. The site was free of standing water when the seeds fell and germinated and continued to be so until the seedlings were established, probably several years. (USDA Forest Service photo)

Figure 4.26 Quality hardwoods in a southern swamp. These tupelo gum trees, like many other broadleaf species growing in wet sites, developed buttressed bases. The site was free of standing water when the seeds fell and germinated and continued to be so until the seedlings were established, probably several years. (USDA Forest Service photo)

Seeds of water tupelo retain viability for up to 14 months of submergence. This is significant, for southern swamps supporting this species are typically flooded throughout the winter and spring months, occasionally remaining under water for an entire year. Thus, water tupelo seeds are able to germinate when the flood waters have drained, while the seeds of competing species, especially baldcypress, have succumbed.

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