R. L. Johnson
Water tupelo (Nyssa aquatica), also called cottongum, sourgum, swamp tupelo, tupelo-gum, and water-gum, is a large, long-lived tree that grows in southern swamps and flood plains where its root system is periodically under water. It has a swollen base that tapers to a long, clear bole and often occurs in pure stands. A good mature tree will produce commercial timber used for furniture and crates. Many kinds of wildlife eat the fruits and it is a favored honey tree.
Regularity: Regularly occurring
-The native range of water tupelo.
Soils and Topography
Soils that commonly support water tupelo range from mucks and clays to silts and sands and are in the orders Alfisols, Entisols, Histosols, and Inceptisols. Most are moderately to strongly acidic; subsoil frequently is rather pervious. Site index of water tupelo for several Midsouth soils ranges from 21 to 27 m (70 to 90 ft) at 50 years (4).
Average summer temperature within the range of water tupelo is 27° C (81° F); average winter temperature is 7° C (45° F). Temperature extremes are 46° to -29° C (115° to -20° F). An average of 231 frost-free days occur annually over its range.
Associated Forest Cover
In several other forest cover types water tupelo may be a minor associate: Longleaf Pine-Slash Pine (Type 83), Slash Pine (Type 84), Slash Pine-Hardwood (Type 85), and Baldcypress (Type 101).
Species associated with water tupelo throughout its range are black willow (Salix nigra), swamp cottonwood (Populus heterophylla), red maple (Acer rubrum), waterlocust (Gleditsia aquatica), overcup oak (Quercus lyrata), water oak (Q. nigra), water hickory (Carya aquatica), green and pumpkin ash (Fraxinus pennsylvanica and F. profunda), and sweetgum (Liquidambar styraciflua). Swamp tupelo (Nyssa sylvatica var. biflora), pondcypress (Taxodium distichum var. nutans), and redbay (Persea borbonia) are common associates in the Southeast.
Small tree and shrub associates of water tupelo include swamp-privet (Forestiera acuminata), common buttonbush (Cephalanthus occidentalis), waterelm (Planera aquatica), sweetbay (Magnolia uirginiana), Carolina ash (F. caroliniana), poison-sumac (Toxicodendron vernix), southern bayberry (Myrica cerifera), and dahoon (Ilex cassine).
Diseases and Parasites
A foliar disease, Mycosphaerella nyssaecola, has caused premature defoliation, but impact has been negligible.
Reaction to Competition
Table 1- Root characteristics of swamp tupelo and water tupelo as affected by drainage (13) Root characteristics Roots well aerated Roots flooded Morpology Small diameter and fiborous except at the apex Succulent with very little branching Epidermis Highly suberized Little or not suberization Endodermis Highly organized, with Casparian strips Poorly organized, Casparian strips not evident Adventitious water root None Prolific just below water line¹ Intercellular space in cortex Abundant Abundant Oxides-
rhizospheres in anaerobic conditions No Yes ¹May be absent on water tupelo under many types of flooding.
Life History and Behavior
There are no practical techniques for reproducing water tupelo through cuttings or layering.
Seed Production and Dissemination
Flowering and Fruiting
Seeds may be sown in fall in the nursery or may be stratified over winter and sown in the spring. For stratifying, seeds are kept in moist sand or plastic bags at 2° to 4° C (35° to 40° F) (30). Up to 30 months storage does not reduce viability of seeds that have a moisture content of 20 percent or less and are kept in polyethylene bags at a temperature of about 3° C (38° F) (3).
Nursery-sown seeds may be drilled 13 to 25 mm (0.5 to 1 in) deep at the rate of 50/m (15/ft) of row, or they may be broadcast and rolled into the soil. A seedbed density of 110 to 165 seedlings/m² (10 to 15 seedlings/ft²) is recommended. From 25 to 37 mm (I to 1.5 in) of sawdust mulch is recommended for broadcast seeds.
Growth and Yield
In poorly drained swamps in the southeastern United States, average annual production of water tupelo stands was found to be between 6.3 and 7.0 m³/ha (90 and 100 ft³/acre). Ten-year average diameter growth for trees free to grow in unmanaged stands on an average site is about 8 cm (3 in) (28). Growth and Yield were tabulated at 10-year intervals for unmanaged stands in the Atchafalaya Basin of southern Louisiana as follows (9):
Age Average D.b.h. Height Total merchantable volume (peeled wood) yr cm m m³/ha 30 16.8 14 156 40 24.1 17 243 50 42.2 25 331 in ft ft³/acre 30 6.6 46 2,225 40 9.5 56 3,475 50 16.6 81 4,725 Under management, a pure even-aged stand carried to 107 cm (42 in) in diameter above the bottleneck is estimated to have an accumulative total yield of 676 m³/ha (48,282 mbf/acre, Doyle log rule) in logs and 441 m/ha (70 cords/acre). These yields are based on an assumed cutting cycle of from 8 to 15 years (28).
Basal areas between 57 and 69 m²/ha (250 and 300 ft²/acre) are not uncommon in pure unmanaged second-growth stands. For a less dense water tupelo stand in Florida, the following volumes were recorded (24):
Age Average diameter above bottleneck Total merchentable volume (outside bark) Basal area yr cm m³/ha m²/ha 60 31.8 355 38.6 70 34.8 429 44.5 in ft³/acre ft²/acre 60 12.5 5,077 168 70 13.7 6,133 194 Growth and yield of water tupelo in plantations are generally unknown. One small 17-year-old planting at a 1.7 by 1.7 m (5.5 by 5.5 ft) spacing on Falaya silt loam had 89 percent survival. The trees that grew best averaged 13.2 cm (5.2 in) in d.b.h. and were 14.9 m (49 ft) tall (5).
Molecular Biology and Genetics
No racial variations or hybrids have been recognized for forest-grown water tupelo.
National NatureServe Conservation Status
Rounded National Status Rank: N4 - Apparently Secure
Relevance to Humans and Ecosystems
Water tupelo wood has fine, uniform texture and interlocked grain. When dried properly, the lumber is used for boxes, pallets, crates, baskets, and furniture. Buttresses of trees growing in flooded areas contain wood that is much lighter in weight than that from upper portions of the same trees. The butt portion is probably best suited for pulping products
Nyssa aquatica, commonly called the water tupelo, cottongum, wild olive, large tupelo, sourgum, tupelo-gum, or water-gum, is a large, long-lived tree in the tupelo genus (Nyssa) that grows in swamps and floodplains in the Southeastern United States.
A large mature tree can produce commercial timber used for furniture and crates. The swollen base of the Nyssa aquatica is the source of a favored wood of wood carvers.
- "ARS Germplasm Resources Information Network (GRIN) - species account Nyssa aquatica".
- Bailey, L.H.; Bailey, E.Z.; the staff of the Liberty Hyde Bailey Hortorium (1976). Hortus third: A concise dictionary of plants cultivated in the United States and Canada. New York: Macmillan. ISBN 978-0-02-505470-7.
- U.S. Forest Service silvics manual - Nyssa aquatica treatment
- Werthner, William B. (1935). Some American Trees: An intimate study of native Ohio trees. New York: The Macmillan Company. pp. xviii + 398 pp.
- New Oxford American Dictionary, 2nd Edition.
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