The Alaska Vegetation Classification - Alaska Geobotany Center ...

Closely related types-Depending on the proportions of the dominant species inthe canopy, these communities might resemble open white spruce, open sprucebirch,open paper birch, or open cottonwood communities. They also could resembleclosed birch-cottonwood-spruce communities but have less canopy cover (25 to60 percent).Primary reference-US. Department of Agriculture 1986.Communities-Betula papyrifera-Populus balsamifera-Picea glauca (see footnote 2).I.C.2.d.Open Spruce-Balsam PoplarDescription-These communities are characterized by white spruce and balsampoplar dominance in the overstory. Total tree cover falls between 25 and 60 percent.Stands described thus far have been dominated by white spruce and balsam poplar.Important shrubs include Salix spp. and Alnus sinuata 2 or more meters (6 or morefeet) tall, and Viburnum edule. Rosa acicularis, Oplopanax horridus, and Rubusidaeus growing 1 to 2 meters (3 to 6 fl) tall. The herbaceous layer includes Epilobiumangustifolium, Cornus canadensis. Trientalis europaea, Pyrola spp., Mertensiapaniculafa, Equisetum spp. and the ferns Athyrium filix-femina, Dryopferis dilafafa,and Gymnocarpium dryopteris. Mosses are common on the forest floor.Distribution and site characteristics-Open white spruce-balsam poplar forestshave been described from south-central Alaska where they occur in rather localizedareas within low shrub vegetation at treeline, just above the elevational limit of openwhite spruce forest. In some locations they appear to be associated withhigh-elevation streams.Successlonal status-The successional status of these stands is unknown.Closely related types-Open spruce-balsam poplar (black cottonwood) communitiesare similar to closed poplar-spruce communities but have less than 60 percent treecover. They also can be similar to open white spruce, open balsam poplar, or openblack cottonwood communities but are dominated by mixtures of coniferous andbroadleaved trees.Primary reference-U.S. Department of Agriculture 1986.Communities-Picea glauca-Populus balsamifera (see footnote 2).bC.3. Mixed WoodlandMixed woodland communities have from 10 to 25 percent total tree cover.Dominance in the tree canopy is shared by both needleleaf and broadleaf treespecies, with each group contributing from 25 to 75 percent of total tree cover.I.C.3.a.Spruce-Paper Birch Woodlandblack spruce or white spruce, or both. Total tree cover is 10 to 25 percent. PublishedDescrIptlon-Spruce-birch woodlands are dominated by mixtures of paper birch anddescriptions of these communities are lacking. Spruce-birch woodlands probably aresimilar to open spruce-birch forests but have less tree cover and the trees generallyare smaller.