33. Paper Birch
Betulaceae
Betula papyrifera
Also known as the White Birch or Canoe Birch
Specimen Size: 43.5ft tall, 16.25in in diameter.
Location: Southeast corner of Thomson Hall, in the planter towards the HUB east of the last entrance steps.
Historical Background: Native people inland from the west coast use the waterproof papery bark for baskets, canoes, roofing tiles, and more. The wood can also be used as fuel and food. The Athabaskan Indians experienced a buzz from chewing on the birch gum, containing terpenes. Birch resin contains a disinfecting compound called zylitol and is sold as a teeth cleaner. In parts of North America, the sap is used in syrups, wine, and beer.
Native
Native Range: Northern North America: Canada, Alaska, B.C., Washington to Montana, and more
Identifying Features: The most distinctive feature of the birch is its white papery bark, peeling in papery strips and flecked with horizontal dark lines of raised pores. In the wet climate of the PNW it is not uncommon for the bark to be split by sections of rougher almost black thick bark which appears due to an abundance of water allowing the tree to swell. Leaves are ovular to round and toothed, tapering to a point and a dull light green on top, lighter and hairy on the bottom. Flowers appear in the form of long hanging catkins extending from twig tips.
Identifying Features In Depth:
Form: Small to medium sized tree, growing up to 100” (30m), often expressing medium apical control and open canopy.
Leaves: Oval to round and pointed on the tip with toothed edges and a dull green color on top (paler and hairy on bottom). Leaves are deciduous and alternate, up to 4’ (10cm) long, and occasionally have shallow lobes. Leave often turn a bright yellow in fall.
Bark: Birch bark often is generally quite distinctive, papery and white to coppery-brown, peeling in strips and covered with dark brown horizontal lines. Older trees or those in wetter climes may experience deep furrowing and thickening of the bark which exposes dark to almost black bark ridged bark (some of which may be seen on this specimen).
Reproductive Bodies: Male and female flowers both appear in separate catkins, hanging protrusions that look somewhat like a bushy cats tail. They are between about 1-2’ (2-4cm), sometimes smaller, and flower at the same time prior to fresh leaves. Catkins break up after flowering and females give way to opposite dual winged nutlets.
Native range of Betula papyrifera in North America, compiled by Native Plants Pacific Northwest.
Below is the description found for this species on the original Brockman Memorial Tree Tour:
Historic Tree Tour Information: At the southeast corner of Thomson Hall stands a white-barked Paper Birch, a species whose native range extends from Alaska all across Canada and the northern United States. Native in Seattle, it is rare here, and is vastly outnumbered by its European cousin Weeping European White Birch. Its leaves are larger than those of the European Birch. Paper Birch also has a whiter trunk. The tree we single out at this stop has been hurt by the wall constructed next to it, so its top is thin and its leaves smaller than when it was healthy. Larger examples can be found elsewhere on campus.
Paper Birch is a pioneer species, quickly recolonizing disturbed land. However it is easily overtaken by other species that reproduce better in shade. The thin outer white bark of this species is easily harvested without killing the tree and is resinous, tough, durable, and waterproof. This was used to make drinking vessels, canoe skins, roofing tiles, buckets, and sunglasses to prevent snow blindness. A brown to red dye can be obtained from the inner bark. The wood is useful as a fuel because it burns well with a considerable amount of heat even when green, but it tends to coat chimneys with a layer of tar.
