River birch

Betula nigra
Family: Betulaceae

Natural Historyriver birch branch
Leaves of river birch
Photo credit: Larry Korhnak, University of Florida

River birch, also called red birch, black birch, or water birch, is the only southern birch that grows in coastal plains. However, it is not very flood-tolerant and may suffer during extended inundation.

Habitat & Range

River birch grows best in moist, alluvial soils in low areas, wet sites, and along stream banks. However, it is somewhat tolerant of acidic and clay soils. It is most often seen with mixed hardwoods.

Wildlife Use

Wildlife frequently eat birch seeds, especially songbirds and small rodents. White-tailed deer are known to browse on the twigs and foliage.

Human Use

The wood, which is strong and able to be turned easily, is used to make woodenware and gift items, as well as for toys, artificial limbs and fuel wood. Extracts from the bark are used in the tanning of leather. Some species in the genera produce extracts that are used to make birch beer, an old-fashioned soft drink. Herbalists make a laxative tonic from the leaves, along with treatments for gout, rheumatism and kidney stones. The leaves and bark have astringent properties that are useful in treating skin eruptions, especially eczema. Birch tea is also said to be effective as a diuretic and to reduce fevers.

The trees are sometimes grown as ornamentals, but are also planted to control erosion. Since the species will grow in acidic habitats, it is often used to help reclaim areas that have been strip-mined and have high residual coal acids in the soil.


 

Identifying Characteristics

Size/Form: River birch is a medium-sized, deciduous tree that grows 70 to 80 feet tall and 15 to 30 inches in diameter. About 15 to 20 feet above the ground, the tree tends to divide into large, arching branches, forming an irregularly spreading crown.
Leaves: The leaves are simple, alternately arranged and diamond-shaped, about 1 ½ to 3 inches long and 1 to 2 inches wide. The leaf margin is doubly serrate, with the lower 1/3 entire and wedge-shaped. The leaf tip is acute. Leaf color is deep green above and paler below, with hairs underneath and on the flattened petiole.
Twigs: The orangish-brown twigs are slender and smooth or slightly pubescent. Additionally, they lack a terminal bud.
Bark: The bark is thick, shaggy, coarsely scaled and peels easily. It is a gray-brown color with a distinct salmon-pink tinge. Young twigs are reddish-brown, slender and hairy, and have a zigzag pattern due to the lack of a true terminal bud.
Flowers: The river birch is a monoecious species. Both male and female flower are greenish-colored catkins.
Fruit: The fruits are small, hairy, winged nutlets encased in a small, cylindrical cone-like structure on a slender stalk.
Similar Trees on the Florida 4-H Forest Ecology Contest List:
There are a few other trees on our list that also have simple, alternate leaves with pinnate venation and serrate margins.

 

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