Paper Birch

Paper Birch (Betula papyrifera and Betula neoalaskana)

Also known as: Canoe Birch, White Birch, Alaska birch and Yukon Birch

Bloom time: April – June

Additional photos:

• Betula papyrifera. Three male catkins hang from the branch tip, while a smaller female catkin extends above the branch.
  credit: G. Powell
• Betula papyrifera leaves
  credit: G. Powell
• Betula papyrifera
  credit: Bob Decker

General:

• There are two closely related species of Paper Birch common in the NWT, Paper Birch (Betula papyrifera) and Alaska Birch (Betula neoalaskana). These species frequently hybridize. Either species of paper birch can be observed as part of the Plant Watch program.

• Other languages:
  • Tli cho, Chipewyan, North and South Slavey: k’i
  • Gwich’in: aat’oo
  • Cree: wuskwi-atik
  • Inuvialuktun: urgiiliq
• A deciduous tree, up to 15-20 m tall (sometimes to 30 m), often with several trunks.
• The bark of mature trees is white when mature, and dark reddish-brown when young, and peels in paper-like strips. The bark is marked with brown horizontal lines of raised pores or lenticels.
• Bark is thin, smooth and darker on young trees.

Leaves & Twigs:

• Leaves are egg- to triangular-shaped, and usually 3 – 8.5 cm long. Leaves have a sharp point at the tip, are greener on the upper surface, paler on the lower surface, and have toothed edges.
• Twigs are brown to red in colour, slender and hairy. The twigs of Alaska Birch are most often covered with sticky resin glands.

Flowers & Fruits:

• Male and female flowers are in separate catkins on the same twigs. Male catkins look like yellowish-brown worms, are 2-10 cm long, and hang from the ends of twig tips.
• Female catkins appear with emerging leaves, stand erect at the branch tips at first bloom and are 2-4 cm long. Female catkins break up at maturity to release winged seeds.
• Fruits are a broad, oval nutlet, with two wings that are wider than the body of the nutlet.
• The flowering event observed for PlantWatch is pollen shed from the male catkins.

Habitat: Paper Birch is found in open to dense woodland. It grows best on well-drained but moist sites, and is widespread across the boreal forest. It needs open sunny spots and grows often in burned or disturbed areas.

PlantWatch Pointers: Tag a large, mature tree with low hanging catkins, for observation. It is best to avoid small shrub-like trees, as these can more easily be confused with other tree and shrub species.

To Observe:

• First bloom: When the male catkins first start shedding pollen in at least 3 different places on the tree. You can check this by flicking a male catkin with your finger, and observing if a small yellow cloud of pollen is visible.
• Mid bloom: About 50% of the male catkins are now shedding pollen
• Leafing: When the first leaves have emerged and unfolded completely in 3 different places on the tree.
• Sap flow: In early spring, PlantWatchers who wish to monitor sap flow can cut the tip of a young twig, and watch for first signs of dripping sap as temperatures warm and record the date of first sap flow in the ‘Comments’ section of the Plant Watch data form.

Distribution Map:

This species is monitored in:

• Alberta
• Newfoundland and Labrador
• Northwest Territories
• Quebec

Many northern Aboriginal nations consider the paper birch to be the most useful tree species. Paper birch is used to make objects including canoes, snowshoes, tipis, baskets, and paper, as well as for medicinal purposes. Birch sap can be collected and boiled down to make syrup, wine, beer and soft drinks. It takes approximately 80-100 liters of birch sap to make 1 liter of birch syrup! In comparison to about 40 liters of sugar maple sap (Acer saccharum) to make one liter of syrup.