The Alaska Vegetation Classification - Alaska Geobotany Center ...

Mature birch can survive low-intensity ground fires, but the aerial parts are easilykilled by moderate and severe fires. If the roots survive the fire, the stumps sproutvigorously, which leads to an abundance of multiple-stemmed trees in the resultingforest.Closely related types-Closed paper birch communities resemble open paper birchcommunities but have a greater overstory cover. Birch communities with spruce understoriesjust beginning to reach into the birch canopy may resemble spruce-birchmixed forest, but they have less spruce in the canopy. If aspen is present, birchcommunities may resemble birch-aspen communities but with less aspen.Photographs-Foote 1983, figures 4 and 5; figure 26, this publication.Prlmary references-Foote 1983, Neiland and Viereck 1977, Viereck and others1983.Communities-Betula papyriferaIAlnus crispa/Calamagrostis spp. (Buckley andLibby 1957, Lutz 1956, Viereck 1975). Betulapapyrifefda/Viburnum edule (Foote1983). Betula PapyriferdAlnus spp.-Salix spp. (Racine 1976). Betula papyrifera/Ledumgroenlandicum/fleurozium schreberi-Polytrichum juniperinurn (Jorgensonand others 1986).I.B.1.e. Closed Quaking Aspen ForestDescription-These stands are dominated by aspen and total tree cover is 60 percentor more (fig. 27). The largest aspen trees reach 25 to 36 centimeters (10 to14 in) in d.b.h. and 18.3 meters (60 ft) in height. Aspen may grow in pure stands orbe associated with small quantities of white spruce, black spruce, balsam poplar, orpaper birch. White spruce seedlings and black spruce regeneration may be present.Tree densities range from 1,200 trees per hectare (480lacre) for mature stands(50 to 80 years old) to 700 trees per hectare (280lacre) for overmature stands.Scattered clumps of Alnus crispa and Salix bebbiana that are several meters tallare commonly present. A broken to nearly continuous shrub layer 1 to 2 meters(3 to 6 ft) high consists primarily of Viburnum edule, Rosa acicular;& Salix spp., andShepherdia canadensis. The herb layer is poorly developed, but scattered plants ofCalamagrostis canadensis, Epilobium angusfifolium, Equisetum arvense, fedicularislabradorica, Linnaea borealis, Geocaulon lividurn, and Galium boreale usually can befound. Mosses and lichens are scarce.Figure 27-Closed broadleaf forest of quaking aspenwith a shrub layer of Rosa acicularis, Viburnum edule,and Shepherdia canadensis; a scattered herbaceouslayer of Calamagrosfis canadensis and Epilobiumangusfifolium; and the creeping subshrub Linnaeaborealis on a south-facing slope with a thick depositof loess in the uplands of interior Alaska89