The Alaska Vegetation Classification - Alaska Geobotany Center ...

hummocky substrate and usually are dominated by Alnus crispa or A. sinuata (asopposed to A. tenuifolia, which typically dominates alder shrub swamps). Red alderis considered a tree, so stands of this species are classified as broadleaf forest.Photographs-Figure 39, this publication.Primary references-Batten and others 1978; Hanson 1951; Racine and Anderson1979; Viereck 1962, 1963.Communities-Alnus crispa/Calamagrostis canadensis (Hanson 1953; Hulten 1960,1962; Jorgenson and others 1986; Racine and Anderson 1979; Viereck 1962; Youngand Racine 1977). Alflus crisp-Salix planifolia/Arcfagrostis latifolia-Equisetumarvense (Craighead and others 1988). Alflus crispdSpiraea beauverdiana (Craigheadand others 1988). Ahus crispa/Festuca altaica-Arcfagrostis latifolia (Craighead andothers 1988). Alnus crispa/Carex bigelowii-Festuca altaica-Arcfagroosfis latifolia(Craighead and others 1988). Alnus crispa/€quisefum arvense (Craighead and others1988). Alnus crispa-Salix glauca-S. planifolia/€quisefum arvense (Craighead andothers 1988). Alnus crispa-Salix arbusculoides-S. glauca/Delphinium glaucum-Aconitumdelphinifolium-Calamagrosfis spp. (Viereck 1963). Alnus sinuata (Battenand others 1978, Cooper 1942, Palmer 1942, Young and Racine 1978). Alnussinuata/Calamagrosfiscanadensis (Hanson 1951; Hulten 1960, 1962; Worley 1980).Alnus sinuafa/Rubus specfabilis (Heusser 1960, lsleib and Kessel 1973, Strevelerand Paige 1971). Alnus tenuifolia (Hogan and Tande 1983, Van Cleve and others1971). Alnus fenuifolia/Calamagrosfis canadensis (Hanson 1953).ll.8.l.c. Closed Tall Shrub Birch ShrubDescription-These communities are dominated by Betula glandulosa or hybrids ofB. glandulosa and 6. papyrifera. The shrub canopy is generally 1.5 meters (5 ft) tallor taller and provides 75 percent cover or more. A few tall willows may be presentbut do not provide much cover.Distribution and site characteristics-Closed tall shrub birch communities arerather uncommon types that occur primarily in forest openings near tree line ininterior Alaska and on moderate, protected slopes beyond tree line in westernAlaska, especially on the Seward Peninsula.SUCCeSSiOnal status-Successional relations are largely unknown. On sites withintree line, these communities are probably late in a successional sequence thatoriginated after some disturbance.Closely related types-Closed tall shrub birch communities resemble other shrubbirch communities (open tall shrub birch, closed low shrub birch, and open low shrubbirch) but differ in having a tall shrub canopy at least 1.5 meters (5 ft) high with acover of at least 75 percent. They also are similar to closed tall shrub birch-willowcommunities but have less willow cover.Primary references-Hanson 1953, Jorgensen and others 1986.Communities-Betula glandulosa (Hanson 1953). Betula glandulosa/Ledumdecumbens-Vacciniumspp. (Jorgenson and others 1986).115