Description and habitat
Yellow Birch (Betula lutea, syn. Betula alleghaniensis) is a large deciduous tree abundant throughout Ontario’s Great Lakes Region. Yellow Birch can grow 35 m in ideal conditions, though most trees are shorter. It is one of Ontario’s 3 birch species – the other two are Paper Birch (Betula papyrifera), which occurs throughout the province, and Cherry Birch (Betula lenta), which is restricted to the several small areas on the Niagara Peninsula. Although Yellow Birch is common throughout its distribution, it increases in relative abundance towards the northern edge of its range. In places like Algoma District (along Lake Superior), or Algonquin Park, Yellow Birch can often dominate entire hardwood forests alongside Sugar Maple (Acer saccharum), though the latter species is usually more common.
Leaves of Yellow Birch are 8-11 cm long, alternately arranged on the twig. They are oval with a cordate (heart-shaped) base, with doubly toothed margins. These leaves can be confused with elm and hop-hornbeam leaves, but elm leaves are asymmetrical, and hop-hornbeam leaves lack the cordate base. Like other birches, Yellow Birch has horizontally peeling bark, but it is golden or bronze, instead of snowy white like Paper Birch. The flowers are in the form of catkins, appearing in May. In August, the catkins release tiny, winged seeds, each only 0.5 cm wide. Crushed twigs have the scent of wintergreen oil.
Yellow Birch occurs in moist and wet forests, most often alongside Sugar Maple (as mentioned), Red Maple (Acer rubrum), American Beech (Fagus grandifolia), and Eastern Hemlock (Tsuga canadensis). It also occurs in raised areas within swamps. Excessively dry or sandy conditions are unfavorable to yellow birch, consequentially it is absent from oak savannas. Yellow Birch can establish on old fields when conditions are favourable, though it is most frequently observed in mature and old-growth forests. In older forests, saplings often grow on fallen logs, called “nurse logs”, which gradually disintegrate as trees reach maturity. Yellow Birch is considered shade-tolerant and fire-sensitive by most ecologists. Overall, Yellow Birch is highly important tree species in the forests of the Great Lakes Region, especially as a wildlife resource.
Wildlife importance
Birch seeds are consumed by a large diversity of small mammals, birds and insects. Insects also feed extensively on the leaves. The foliage is a highly important larval food source for butterflies and moths, including the Mourning Cloak Butterfly (Nymphalis antiopa), Compton Tortoiseshell Butterfly (Nymphalis vaualbum), Slug Moths (Family Limacodidae), Ached Hooktip Moth (Drepana arcuata), Tufted Thyatrid Moth (Pseudothyatira cymatophoroides), Dotted Grey Moth (Glena cribrataria), Banded Tussock Moth (Halysidota tessellaris).
Fun facts
- Yellow Birch sap can be tapped and made into syrup, though the sap flow is less abundant than maple, thus requiring more boiling. Birch syrup has a more distinct, caramel-like flavor compared to maple syrup.
- Yellow Birch is a versatile tree species, capable of growing on rocky slopes and in acidic soils. It is long-lived and hardy tree, bearing strong, economically valuable hardwood.
- In cool microclimates, Yellow Birch often grows alongside Eastern Hemlock, offering a unique habitat for a variety of northern species within the Long Point Basin.
- The wintergreen oil mentioned earlier (methyl salicylate) was historically extracted from the bark and twigs of Yellow Birch through distillation. This oil had various medicinal and flavoring uses, although it has largely been replaced by synthetic versions today. Indigenous peoples in Canada also had traditional uses for the bark and sap.
- Methyl salicylate from birch is also utilized for medicinal purposes, especially as an antimicrobial.
Written by Matthew Palarchio, HBSc in Environmental Sciences, Western University.
Photo Credits (L-R)
Growth Form © Matthew Palarchio
Bark © Matthew Palarchio
Leaves © Carter Dorscht
Birch Forest © Matthew Palarchio
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