Water Birch
©Jo-Ann Ordano, California Academy of Sciences
Betula occidentalis, Bark
©Copyright Steve Baskauf, 2002-2005
Male and Female Catkins
©www.borealforest.org
Betula occidentalis, or water birch, is a member of the Birch family, Betulaceae. It is also known by several other names such as red birch, black birch, spring birch, mountain birch, and Rocky Mountain birch. It is a deciduous perennial tree that can grow up to 33 feet in height and each trunk can be up to 14 inches in diameter. It generally produces more than one trunk over its lifetime, which makes it look more like a dense, large shrub. It can create thickets due to its ability to grow many small trunks from the base. The crown of the tree is rounded, and it has drooping branches. The bark is thin and can be reddish brown, black, or yellowish-brown with horizontal lines in the bark (see left middle picture). The leaves are small, simple, and alternate. They are oval or elliptical in shape and green, with serrated edges. The leaves are 0.5 to 2 inches long and 0.25 to 1.6 inches wide.
Distribution:
Water birch is native to the U.S. and is found in much of the western half of the United States as well as Alaska. It is found extensively in the Rocky Mountains along streamsides and other riparian regions. Its dense rooting system keeps streamsides from sloughing off. It grows along with other riparian species such as cottonwoods (Populus spp.), willows (Salix spp.), and box elders (Acer negundo). It can be found in Ponderosa pine (Pinus ponderosa), Engelmann spruce (Picea engelmannii), and Douglas fir (Pseudotsuga menziesii) communities, as well as in big sagebrush communities (Artemisia tridentata), but requires a moist soil to survive. In Utah, it is found at an elevation between 4,000 and 8,800 ft (1220 to 2680 m), but has been found as low as 2,000 ft (610 m) in California and as high as 9,500 ft (2896 m) in Colorado.
Reproduction:
Water birch is a monoecious plant, meaning each tree has both female and male reproductive parts. The plants produce male catkins in summer which become active the next spring when they release their pollen. Female catkins grow along with the leaves and, after being pollinated, grow into cone-looking structures. The seeds are retained in double-winged samaras. The very small seeds are dispersed by the wind and need light to germinate. In Utah, water birch flowers in May to July with bright yellow flowers.
Uses:
Water birch primarily is used for forage for sheep and other animals. It is not used extensively for wood products, medicinal use, or food. As mentioned above, it may be very useful in assisting in erosion control of rivers and streams due to its extensive rooting system.
Interesting Facts:
**Water birch can hybridize with paper birch, which is found in Oregon, Idaho, Washington, and British Columbia. This hybridization produces many different birch forms.
**Because of the dense thickets it can create, water birch stands can become cover for wildlife.
**Water birch trees grow many branches, which are used by beavers to construct dams.