papyrifera – Latin for ‘paper-bearing’ from papyrus meaning ‘paper’ + fetura meaning ‘bearing’ or ‘producing’

Native range: North America

Leaves:

• alternate
• simple
• serrate
• ovate (much larger than B. pendula)
• rounded base
• deciduous stipules

Flowers:

• males:
  • pendulous catkins
  • w/ 3 flowers in each scale axil
• females:
  • short
  • 3 flowers in axils

Fruit:

• winged nut
• scale-like bracts
• 1/8”
• T-shaped

Other characteristics:

• deciduous tree or shrub
• bark grayish white
• lenticels in bark
• bark will peel in horizontal strips

Relevant info:

• maximum height is reached at 60-70 yrs
• rarely lives longer than 140 yrs
• root sprouts, found in groves
• native to Washington north of Everett
• bark can be peeled off in large, flexible, waterproof sheets, which were used by native people inland from the NW Coast for canoes and baskets

Ecology & Adaptations:

• native to Alaska to Oregon, east of the Cascades except in northwest Washington, east to the Atlantic coast
• found in moist, open to dense woods, from lowlands to lower mountain slopes
• typically on well-drained sites but also on or around bogs and other wetlands and alluvial (riverine) sites
• sexual reproduction:
  • male catkins are partially formed in the fall, remain dormant in the winter, and expand to a length of about 4 inches (10 cm) before flowering in the spring
  • female catkins appear in the spring before the leaves are fully expanded.
• pollination by wind
• seed dispersal – light, winged seeds are dispersed readily by wind
• vegetative regeneration:
  • sprouts from stump base or root collar following cutting or fire
  • re-sprouting vigor diminishes with age of tree
• adapted to wetlands:
  • lenticels (pores) in bark enable transfer of oxygen to roots in saturated soil
  • shallow root system increases access to oxygen
• herbivore defense – leaves contain condensed tannins that reduce digestibility of tissue by binding with proteins
• succession – shade-intolerant species rapidly colonizes open disturbed sites created by wildfire, windthrow, or avalanche but lasts only one generation (cannot self- replace) before it is replaced by shade-tolerant conifers or northern hardwoods
• adapted to fire:
  • at the population level, recovers quickly by means of seedling establishment and vegetative regeneration
  • undamaged trees needed to re-colonize exposed mineral soils of burned areas
  • thin bark renders young trees susceptible to injury, though thick bark of older trees is more flammable once it begins to exfoliate
  • compared to conifer-dominated forest types, canopy has a high moisture content and the understory is lush so crown fires may stop at the boundary of large birch stands or become slow-moving ground fires
  • large paper birch trees often survive fire in pure stands, and thus become seed trees for post-fire establishment
• wildlife – deer and moose browse twigs in winter