(Upload on September 26 2012) [ 日本語 | English ]

Betula papyrifera Marsh.

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

Betula L. (カバノキ)
Kamikanba (カミカンバ, 紙樺) * tentative translation (not in wide use), paper birch (American white birch / canoe birch)
Lifeform: deciduous tree < 30 m high
Distribution: boreal regions in North America (even in Washington State)
Habitat: a pioneer tree after various disturbances, including wildfire (森林火災) and logging
Varieties: regional populations
var. papyrifera
var. commutata (Regel) Fern. (western paper birch)
var. cordifolia (Regel) Fern. (mountain paper birch)
var. kenaica (W. H. Evans) Henry (Kenai birch)
var. neoalaskana (Sarg.) Raup (Alaskan paper birch)
var. subcordata (Rydb.) Sarg. (northwestern paper birch)

Betula species in Alaska

1. Leaves rounded in apex

2. Leaves small up to 2 cm long, crenate, serrate, petioles short, densely fine-pubescent; wing of nutlets narrow

3. Leaves orbicular, with truncate or cordate base, often broader than long, crenulated all around; decumbent dwarf shrub ___ B. nana ssp. exilis, dwarf birch
3. Leaves obovate, with cuneate toothless base; upright shrub _____ B. glandulosa, shrub birch

2. Leaves large ___ B. nana × B. glandulosa

1. Leaves acute or somewhat acute in apex

2. Leaves yellowish-green, especially below, with distinctly prolonged caudate apex _____ B. occidentalis
2. Leaves dark green, paler below, lacking caudate apex

3. Leaves triangular or diamond-shaped, with white hairs in margin; wings of nutlet as broad as body or narrower _____ B. kenaica
3. Leaves ovate, double-serrate; wings of nutlet broader than boty _____ B. papyrifera var. commutata

(Hultén 1968)

Betula papyrifera in Alaska

var. neoalaskana

Birch1 Birch2
[1/2] at Poker Flat that was burnt in the summer of 2004 on August 10 2012.