Information on the Birch Tree

Birch trees are an elegant addition to most backyards, but beware the pollen.

The birch tree is considered an ornamental tree. This means the tree either produces flowers, scent or fruit, requires maintenance, or possesses distinguishing features. These attributes make ornamentals common additions to gardens. To meet the demands of its ornamental status, birch trees require yearly raking of their leaves. The birch tree features distinctive bark and an elegant appearance.

Habitat/Species

Over 40 species of birch tree thrive in the Northern Hemisphere, including the white birch, silver birch, black birch, river birch and yellow birch. The tree flourishes from planting zones 1 to 10, which range from Alaska to Texas. This means that the tree has a high cold tolerance since zone 1 possesses an average low temperature of -50 degrees F. The tree adapts extremely well as zone 10 has an average low temperature of 40 degrees F. Many species of birch thrive within the same range in the Eastern Hemisphere. Most species live in cooler climates like Pennsylvania, Canada and Minnesota.

Characteristics

The birch tree has peeling bark in various colors from red to white. The loss of too much bark kills a birch tree. If it doesn't peel, then the tree bark is textured, like the striped birch tree's green and white bark. Birch trees generally grow thin and tall, looking like a graceful ballerina. It may have one stem or many and reach 50 to 80 feet in height. The tear drop-shaped leaves turn yellow in autumn before the tree drops its leaves to prepare for winter. The birch tree generally lives about 50 years, though some species like the white birch live only 20 years. It prefers moist soil for its shallow root system.

Uses

Birch trees, with the help of humans, are turned into paper, hence the common name of paper birch, belonging to the white birch. Birch tree wood is used to make furniture and fuel for wood stoves. The sap makes candy, syrup and birch beer. The Native American used the bark of the birch, particularly the white birch, for canoes, wigwam coverings, hunting and fishing gear, musical instruments, decorative fans, sleds, toys, containers and beadwork.

Reproduction

Male and female catkins, the flower and seed of the tree, grow on the same tree. The male catkins begin to grow in late fall. The female caterpillar-shaped catkins bloom in spring. The wind carries the pollen on the wind to fertilize other trees. The catkin dries in late summer to early fall. The wind, birds and other wildlife carry the winged, paper-thin, insect-like seed to its new resting place, where it hopefully, germinates.

Allergy

Landscapers like to use the birch tree because of its unusual texture, visual appearance, and grow-anywhere adaptability. This puts the birch tree in the backyard of many homes. Unfortunately, the birch tree produces pollen that instigates allergic reactions. Allergy sufferers combat the tree's pollen with antihistamines and avoidance of the tree. Seventy-five percent of people with a birch allergy also suffer from oral allergy syndrome. A chemical, similar to birch pollen, produced in fresh fruits, nuts and vegetables like sunflower seeds, cucumbers, and bananas incites itching, burning and lumps in the mouth.

References

• NativeTech: Native American Technology and Art: Uses For Birch Bark
• United States National Arboretum:Beautiful Bark: Beyond Flowers, Fruit, and Foliage
• Alaska Science Forum: Birch Sap Sugaring Off
• Pollen Auckland Allergy Clinic: Pollen Allergy and Cross-Reactions in New Zealand
• USDA Forest Service: How to Grow and Maintain a Healthy Birch Tree

Resources

• Department of Forestry Virginia
• Arbor Day Foundation