The Alaska Vegetation Classification - Alaska Geobotany Center ...

Figure 38-Closed tall willow shrub of Salixinmterior,S. alaxensis, S. novae-angliae, S. brachycarpa, andS. lasiandra and an herbaceous layer of Equiseiumarvense and E. pramtense on a river flood plain ininterior Alaskawillow stands slowly degenerate as the permafrost table rises. The willow standsbecome lower and more open and are eventually replaced by wet sedge meadowor tussock tundra types. Successional relations of stands on sheltered upland slopesare less clear. Some of these stands may persist for long periods.Closely related types-Closed tall willow communities are similar to open tall willowcommunities but have greater than 75 percent of their cover in tail shrubs. They alsoare similar to closed low willow communities, but the canopy height is generallygreater than 1.5 meters (5 ft). They are similar to closed tall alder-willow communitiesbut have little or no alder. Some of the moister closed tall willow stands, particularlythose dominated by Salix planifolia, S. lanafa, or S. barclayi, may closely resemblesome closed tall shrub swamps, but the shrub swamps are wetter with permanent orsemipermanent standing water.Photographs-Figure 38, this publication.Primaty references-Bliss and Cantlon 1957, del Moral and Watson 1978, Hanson1953, Racine and Anderson 1979, Viereck 1963.Communities-Salix alaxensis (Bliss and Cantlon 1957, Brock and Burke 1980,Craighead and others 1988, Griggs 1936, Hanson 1953, Johnson and others 1966,Pegau 1972, Racine and Anderson 1979, Spetzman 1959, Viereck 1963). Salixalaxensis/Calamagrostis spp.-Equisetum arvense (Farjon and Bogaers 1985). Salixalaxensis/€quisefum arvense (Craighead and others 1988). Salix alaxensis-S. glauca-S. lanata (Drew and Shanks 1965, Komarkova and Webber 1980, Spetzman 1959,Wiggins and Thomas 1962, Young 1974b). Salix alaxensis-S. glauca-S. planifolirdEquisetum arvense (Craighead and others 1988). Salix alaxensis-S. planifolia(Johnson and others 1966, Young and Racine 1977). Salix alaxensis-S. planifolia-Ahus tenuifolirdVaccinium uliginosum-Betula glandulosa (Jorgenson and others1986). Salix alaxensis-S. arbusculoides-S. glaucd€quisetum arvense-Pyrolagrandiflora (Batten 1977, Bliss and Cantlon 1957). Salk alaxensis-S. arbuscu/oides/Calamagrosfis canadensis-Equisetumprafense (Hulten 1966). Salix planifolia(Craighead and others 1988, Hopkins and Sigafoos 1951, Hulten 1962, Johnsonand others 1966). Salixglauca-S. planifolia-S. lanafa (Batten 1977, Childs 1969,Griggs 1936, Hanson 1953, Koranda 1960, Pegau 1968, Racine 1977, Racine andAnderson 1979, Viereck 1962). Salix barclayi(de1 Moral and Watson 1978, Hulten1960).113