The Alaska Vegetation Classification - Alaska Geobotany Center ...

and others 1988). Picea glaucdAlnus cfispa-Salix spp./Vaccinium uliginosum!leathermosses (Craighead and others 1988). Picea glaucdvacciniurn uliginosum-Carex bigelowii (Craighead and others 1988). Picea glaucdLedum groenlandicum-Vaccinium vifis-idaealfeathermosses (Dyrness and others 1988). PiceaglaucdAlnusfenuifolidArctosfaphylos uva-urssiilichen (Dyrness and others 1988).l.A.3.d. Black Spruce WoodlandDescription-These open stands have a total treecover of 10 to 25 percent and are dominated byblack spruce (fig. 21). Paper birch and tamarackmay be present but provide little cover. Trees ofthese communities are very slow growing, withthe largest trees (over 100 years old) being onthe order of 15 centimeters (6 in) d.b.h. and11 meters (37 ft) tall, or smaller. Tree density isoften surprisingly great considering the opencanopy. Densities of 445 to 2900 stems perhectare (180 to 1,200 per acre) for stems withdiameters greater than 2.5 centimeters (1 in)have been reported. Basal areas are from 0.3 to6.8 square meters per hectare (1.3 to 30 ft2 peracre). Most stands have enough black spruceregeneration, usually by layering, lo maintain thewoodland cover.Tall shrubs in these stands consist of scatteredclumps of Alnus crispa 1 to 3 meters (3 to 6 11)tall, Betula glandulosa, sometimes with willowssuch as Salix lanafa, S. planifolia, and S. glauca.Low shrubs are common in most stands andinclude Vacciniurn uliginosurn, V. vifis-idaea,Ledum decumbens, L. groenlandicum, andEmpetrum nigrum. The herb layer ranges fromsparse to dense. Common herbs include Carexspp., Eriophorum vaginatum, Calamagrosfiscanadensis, Rubus chamaemorus, and Geocaulonlividum. The moss and lichen layer is continuousor nearly so. The mosses Hylocomium splendens,Pleurozium schreberi, and Sphagnum spp.generally dominate beneath the shrubs. AlthoughSphagnumspp. are commonly dominant, theyare absent or nearly so from some communities.On moist and wet sites, the areas between thetrees are usually dominated by shrubs and theassociated mosses. On drier sites, the shrubs arerestricted to the vicinity of the trees; the openingsbetween trees are occupied by fruticose andfoliose lichens (fig. 22). Important lichens includeNephroma arcficum, Cladonia spp., Cladina spp.,Cetraria spp., and Pelfigera spp.Figure 21-Needleleaf wocdland of blackspruce with a low shrub layer of Befulaglandulosa, Ledum groenlandicum, andVaccinium uliginosum and a scatteredherbaceous layer with Eriophorumvaginarum and a moss and lichen layer ofSphagnum, feathermosses, and Cladoniaspp. on a toe slope in interior AlaskaFigure 22-Needleleaf woodland of blackspruce with a scattered shrub layer ofVaccinium uliginsoum and Ledumgroenlandicum and a nearly wntinuouslichen layer of Cladonia spp. andPelrigera spp. on a well-drained soil ininterior Alaska81