The Alaska Vegetation Classification - Alaska Geobotany Center ...

Successional status-Successional relations are mostly unknown. Many standsmay be fairly stable. Drying trends may produce changes toward shrub-tussocktundra. Increased moisture may cause a decrease in willows and shift toward wetsedge meadow.Closely related types-Willow-sedge tundra is similar to open low willow communitiesbut has a strong sedge component. They are similar to willow-graminoid bogsbut occur in tundra (arctic) settings. They also are similar lo sedge-willow tundra buthave more than 25 percent shrub cover, primarily willows.Photographs-Figure 48, this publication.Primary references-Komarkova and Webber 1978, Webber and Walker 1975,Webber and others 1978.Communities-Salix planifolia-Carex aquafilis (Komarkova and Webber 1978, 1980).Salk lanata-Carex aquafilis (Webber and Walker 1975, Webber and others 1978).Salix lanafa-Carex vaginata/Hylocomium splendens (Hettinger and Janz 1974). Salixlanafa/Carex spp. (Craighead and others 1988). Salix planifolia-Spiraea beauverdiana/Carex aquafilis (Hulten 1966). Salix p/anifolia/Carex bigelowii (Craighead and others1988). Salix planifolia/Carex bigelowii-Pefasites frigidus/Hylocomium splendens(Hanson 1958, Hettinger and Janz 1974). Salix planifolidcarex podocarpa-Pefasifesfrigidus (Anderson 1974). Salix planifolia/Carex bigelowii-Arctagrostis lafifolia(Churchill 1955).ll.C.2.1. Open Low Willow-Graminoid Shrub BogDescription-These communities have 25 to 75 percent cover of shrubs at least20 centimeters (8 in) tall, primarily willows. Shrubs taller than 1.5 meters (5 ft)provide less than 25 percent cover, and tree canopy cover is less than 10 percent.Dominant willows include Salix barclayi, S. commufata, and probably others. Scatteredindividuals of shrub birch (Betulaglandulosa and €3. nana) sometimes arepresent. Trees are absent or scarce. Understory dominants include Calamagrostiscanadensis. Carex aquafilis, and C. pluriflora. Nonsphagnaceous mosses areabundant in some sites. Sphagnum is sometimes present. Lichens are absent orsparse.Distribution and site characteristics-Willow-graminoid bogs occur in wet streambottoms and lowland depressions in interior, southwestern, south-central, and southeastAlaska, but peat is generally thin. Permafrost is generally absent.Successional status-Successional relations are largely unknown. If the substratesurface builds up or the water level drops, trees may invade, which leads to forestdevelopment. Willow graminoid bogs sometimes develop from wet meadows or bogmeadows.Closely related types-These communities are similar to willow-sedge tundra butoccur within the trees (subarctic lowland sites). They are similar to open low willowcommunities but have a strong component of grasses or sedges in the understory.Some stands may be similar to sweetgale-graminoid bogs but have more willows andless sweetgale. Some may be similar to open tall scrub swamps but are not as talland lack a significant alder component.Photographs4iogan and Tande 1983, plates 20 and 21,140