Range and Habitat
Yellow Birch (Betula alleghaniensis) is a native tree that ranges from southern Newfoundland and Nova Scotia west across Canada to Minnesota, and south to New Jersey and Pennsylvania, then further south in the Appalachian highlands to northern Georgia. The northern limit of its range closely parallels the 50 degrees north latitude line. Yellow Birch favors the moist, well-drained soil of mountain slopes and ravines; it is especially common in the transition zone between low elevation hardwoods and higher elevation Spruce and Balsam Fir. Further south in its range, it finds the cool habitat that it prefers in swamps, although these trees tend to be less robust than those growing in upland habitats. It will not grow well on dry soils and is intolerant of drought.
Description
Yellow Birch is the largest and longest-lived member of its genus in North America, with an average height of 20 – 25 meters (65 – 80 ft.) and a lifespan of 200 years. On favorable sites it may reach 30 meters (100 ft.) and live for over 300 years. An old growth specimen on Mount Wachusett in Massachusetts is estimated to be 400 years old! The bark on young trees is silvery to golden yellow, somewhat shiny, and peels in thin, horizontal strips; the bark on older trees develops thick, irregular plates. The relatively shallow root system is comprised of several large lateral roots. The leaves are ovate, double-toothed, and up to 12 cm long; they turn an attractive yellow in autumn. Twigs have a pleasant wintergreen odor and are used to make a tasty tea.
Flowers and Fruits
The male catkins form in late summer at the twig tips and expand the following spring, soon releasing their pollen. Female catkins form in early spring to receive the wind-borne pollen; they ripen to become cylindrical, brown aments, each holding hundreds of tiny, winged seeds. The seeds are dispersed by wind, sometimes with the help of small birds, who scatter them as they feed. The seeds can travel 100 meters from the parent tree, and those that land on crusted snow may travel considerably further. Germination is usually the following spring, but some seeds survive in the soil into the second year, showing a slight ability to seed bank. Seedlings are moderately shade-tolerant, but will not long survive under a closed canopy, they require a light gap created by treefall or other forest disturbance.
Wildlife Value
The seeds are favored by Chickadees, Goldfinches, Pine Siskins, Redpolls, and other small passerines. Red Squirrels are known to harvest and cache the mature aments as a winter food supply. Yellow-Bellied Sapsuckers drill rows of feeding holes in Yellow Birch to consume the free-flowing sap; these coincidentally feed other birds and are also visited by insects. Beavers and Porcupines strip the bark of young trees as a food source, which is sometimes fatal to the tree. The leaves and twigs of Yellow Birch, and its relatives Paper Birch and Black Birch, are highly preferred by Moose, White-tailed Deer, and Snowshoe Hare. One study found a browse index rate of 4 for Birch twigs, meaning they were consumed at 4 times the expected rate compared to their availability.
Disease
The Bronze Birch Borer (Agrilus anxius) is a small native beetle whose larvae burrow into the bark and feed on the vascular tissue of several Betula species. Although it is ornamental birches, such as European White Birch, that are most often affected, native birches are also attacked. Look for characteristic D-shaped exit holes in the bark (about 5 mm in diameter) made by the adults as they exit the tree. In a heavy infestation several of the branches, and sometimes the entire tree, can die, with die back beginning at the top of the tree and spreading down.
Wood
Yellow Birch is the most important hardwood for the logging industry in Quebec, where roughly half of all Yellow Birch trees grow; not surprisingly, Yellow Birch is the provincial tree of Quebec! Most wood sold as Birch is this species. The wood is medium-heavy and medium-hard, with reddish brown heartwood and cream-colored sapwood. It is strong but easily worked, and is used for making fine furniture, doors, flooring, cabinets, veneer, and plywood.
Specimen photo
References
Peattie, Donald Culross. 1950. A Natural History of Trees of Eastern and Central North America. Houghton Mifflin, Boston.
Sullivan, Janet. 1994. Betula alleghaniensis. In: Fire Effects Information System [online]. United States Department of Agriculture. United States Forest Service.