Yellow Birch
Seeing the Forest Through Its Trees, Part XIII
By Larry Ely
Yellow birch (Betula alleghaniensis) is one of the three co-dominant species of northern hardwood forests which also includes sugar maple and American beech. It is also the largest tree found here except for towering white pines. While yellow birch shares space in the forest with beech and sugar maple and other species including hemlock, it is much less shade tolerant, though more so than white birch, and its young saplings are unable to germinate on thick leaf litter or to thrive under a deep over-story among the maples and beech.
Yellow birch produces abundant seeds from catkins at maturity in late fall that are spread widely throughout the forest. When those seeds land on a site such as a tree stump or mossy log under a canopy opening in a cool, moist upland site or mountain ravine, the seeds germinate and begin to thrive. A large yellow birch may appear to stand on stilts made of its airborne roots. Those roots originally began perched upon an old stump or log which then decayed. Yellow birch will also wrap its spreading shallow roots around a boulder or rock outcropping where the seed germinated in a soil filled crevice. With its unique requirements, it is usually found in patches throughout the northern hardwood forest and not in pure stands. Yellow birch is adaptable enough that it is found among drier sites joining otherwise pure stands of white birch following disturbance on those sites.
“A large yellow birch may appear to stand on stilts made of its airborne roots.”
Unlike white or paper birch, this relative is much longer lived, typically 150 to 300 years, and might reach a height of 85-feet or more along with a 3-foot diameter. The mature yellow birch is identifiable by its shiny, yellow-bronze bark that flakes and peels in small horizontal strips. Forester Katie Stuart finds it to be among the most beautiful of trees in a forest when the yellow bark is glistening in the sun from a recent rain. Older trees with a diameter over one-foot begin to show a darker gray-brown bark that is somewhat platy and no longer shredding.
The tree’s wood is yellowish with a close grain, hard, strong and heavy and was often thought of as the most valuable timber tree in our woods. The heartwood is a lovely reddish color, often called red birch. It is used for furniture making, interior finishing, cabinetry, and other wood products and provides excellent heat as firewood. Its bark is an excellent fire starter and saplings were once cut in the thousands to distill wintergreen oil from its sap, leaves, and twigs for gum and candy. One quart of wintergreen oil was generated from 100 saplings - today it is synthesized in laboratories.
Yellow birch is very important to wildlife, providing food from its seeds and breeding habitat for many bird species including pileated woodpeckers, black-capped chickadees, pine siskin, and common redpolls. Yellow-bellied sapsuckers rely upon its sap for summer food. White tailed deer enjoy the leaves of seedlings through summer and the woody stems in fall, often challenging success of those seedlings.
Donald Culross Peattie writes of the yellow birch at life’s end “… when a Yellow Birch comes to the end of its life-span, it stands a long time, though decay is going on swiftly under the bark. Such a tree is then nothing but a skin of bark stuffed with punk wood.” When that tree comes down, it is ready for new life to emerge from its remains.
This is part of a continuing series looking at the life of the common trees in our Mahoosuc Mountain Region.
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