The Alaska Vegetation Classification - Alaska Geobotany Center ...

I.C.2.b. Open Quaking Aspen-Spruce ForestDescrlptlon-These communities are dominated by mixtures of quaking aspen andwhite or black spruce. The Only communities described (Yarie 1983) have had blackspruce as the codominant species; however, open aspen-white spruce stands areknown to exist. Both aspen and black spruce are stunted, rarely reaching 10 centimeters(4 in) d.b.h. The aspen usually are taller than the spruce. In one standdescribed, reproduction of both aspen and black spruce was present but not insufficient quantities to make canopy closure likely.Common understory low shrubs include Rosa acicularis, Vaccinium uliginosum,V. vitis-idaea, and Empetrum nigrurn. Common herbs include Cornus canadensis,Epilobium angustifolium, Calamagrostis canadensis, and Pedicularis spp.Dlstribution and site characteristics-Open aspen-black spruce stands arecommon on uplands of the Porcupine Plateau. The soils generally are PergelicCryorthents or Pergelic Cryaquepts. They are poorly drained but may be relativelydry because the surface organic layer has been removed by fire.Successional status-Open aspen-black spruce stands are common on burnedoverlands that previously supported black spruce. These stands probably will persistfor some time, until the shorter lived aspen drops out of the stand and the surfaceorganic layer becomes thick enough and the soils cold enough to inhibit growth ofaspen roots and root suckers. The resultant climax vegetation is expected to beopen black spruce or open black spruce-white spruce forest.Closely related types-Open aspen-spruce communities are similar to open aspen,open white spruce, and open black spruce communities but consist of more or lessequal mixtures of both aspen and spruce. They also are similar to closed aspensprucecommunities but have less than 60 percent tree cover.Primary reference-Yarie 1983.Communities-Populus tremuloides-Picea mariana/Vaccinium uliginosumPolyfrichum spp. (Yarie 1983).l.C.2.c. Open Paper Birch-Balsam Poplar-Spruce ForestDescription-Described stands fitting this community have been dominated bywhite spruce, paper birch, and black cottonwood. All three species grow taller than10 meters (32 ft). Tall shrubs include Alnus spp. and Salix spp. Common low shrubsinclude Vaccinium uliginosum, V. vitis-idaea, Cornus canadensis, Empetrum nigrurn,Spiraea beauvefdiana, Rubus arcticus, Rosa acicularis, and Ledum groenlandicum.Common herbs include Calamagrostis canadensis, Equisetum spp., €pilobiumangustifolium, Trientalis europaea, Merfensia paniculata, Streptopus amplexifolius,and Geranium erianthum.Distribution and site characteristics-Spruce-birch-cottonwood forests have beendescribed from creek bottoms in south-central Alaska.Successional status-The balsam poplar or cottonwood is expected to drop out ofthe stand over time, thereby leaving white spruce and paper birch. Over even moretime, the paper birch also may drop out. In some south-central Alaska settings, paperbirch appears to regenerate itself and persist in climax associations (Neiland andViereck 1977).105