Classification Distribution Vegetation Accuracy

Tree canopy cover is less than 10% (or absent). Shrub birch, ericaceous shrubs and low willow (20 centimeters to 1.5 meters tall) individually contribute 25% to 75% of the total shrub cover; and total shrub cover is 25% to 100%. The class is comparable to the Viereck et al. (1992) hierarchical levels closed low scrub (IIC1), and open low scrub (IIC2).

The low shrub birch-ericaceous-willow landcover class is an ecologically broad class ranging from sites dominated by open willow to Betula nana and ericaceous shrubs. The class is a dominant type above the boreal forest region and below alpine on gentle to moderate slopes within the foothills and broad valleys bordering the Kantishna Hills, the north side of the Alaska Range, and within Broad Pass. The elevation ranges from 204 to 1,068 meters based on field data (Table 3). It dominates several ecoregions including the Cook Inlet-glaciated hills and plains, Alaska Range-front range, Alaska Range-Kantishna Hills and Alaska Range-Teklanika mountains and plateaus ecoregions (Tables 4a and 4b; Clark 1998). It covers 9.5% (570,700 acres) of Denali National Park and Preserve (Table 5). Because this class covers a wide range of site conditions across the park, it is found adjacent to numerous landcover classes. However, it is most commonly found elevationaly above needleleaf classes and mixed in with other shrub classes.

Species composition and cover often fluctuate within and between sites. The dominant species are Betula nana, Chamaedaphne calyculata, Salix barrattiana, S. glauca, S. planifolia, Ledum decumbens, Vaccinium uliginosum, and Empetrum nigrum. Herbaceous species include Achillea species, Calamagrostis lapponica, Epilobium angustifolium, and Rumex species. Mosses are common on some sites and lichens are rare.

The producer’s accuracy for the low shrub birch-ericaceous-willow class is 83.4%, with a user’s accuracy of 75.3%. Most of the errors of commission and omission are with the low shrub-sedge class.