The Alaska Vegetation Classification - Alaska Geobotany Center ...

lll.A.2.b. Bluejoint-HerbDescrlpflon-Bluejoint-herb communities are dominated equally by bluejoint(Calamagrostis canadensis) and various herbs, commonly including Epilobiumangusfifolium, Angelica lucida, Athyrium filix-femina, Equisetum arvense, andE. fluviafile. Sedges and other grasses, such as Carex macrochaeta, Deschampsiaberingensis, and Festuca rubfa, also may be present in significant amounts. Woodyplants are absent or scattered. Feathermosses may be absent or common andfolytrichum spp. are sometimes present. Sphagnum spp. are sometimes presentin small quantities on certain wet sites. Lichens are scarce or absent. The canopyis about 0.8 to 1.5 meters tall, sometimes taller. Cover usually is complete or nearlyso. Productivity of a mesic stand in south-central Alaska was determined to be465 grams per square meter per year (4,150 Ib/acre), primarily €pilobium angustifoliumand Calamagrostis canadensis (Mitchell and Evans 1966).Dlstrlbutlon and site characterlstlcs-Bluejoint-herb communities are common inthe southern half of the State and occupy the same wide range of sites as bluejointmeadows: flood plains, upland slopes from valley bottoms to tree line, streambanks,and fens. Soils also are similar to those of bluejoint meadows, usually silts or loamsor sometimes sedge peals. They may be extremely wet (flooded with 10 to 30 centimeters[4 to 12 in] of fresh water) but more commonly are mesic. The wetter sitesusually have a hummocky microrelief pattern. Soil reaction is moderately acid,generally pH 5 to 6 (minimum value reported is pH 4.4). A layer of decaying plantmaterial often is present at the surface but usually is not as thick as in pure bluejointstands. Permafrost has not been reported from any of these communities but mayexist at depths of 1 meter (3 11) or more under stands in western Alaska.Successional status-In southwestern Alaska, bluejoint-herb communities maydevelop from fell-fields as soils become richer and deeper and from dwarf birchericaceousshrub communities as drainage improves (Griggs 1936). Where drainageand soil development are adequate, the bluejoint may eventually suppress the herbsthereby resulting in the bluejoint-alder grassland climax of that area.In the forested parts of the State, most of the mesic bluejoint-herb communities.havedeveloped when fire, land-clearing, or some other disturbance destroyed forest communities.If disturbance is not renewed, most of these stands eventually are invadedby shrubs (alder or willow, or both) and transformed to scrub vegetation and ultimatelyforest. If shrub invasion is delayed long enough, the bluejoint may crowd out otherherbs, thereby producing a bluejoint meadow.The wet types may be derived from wet sedge meadows or wet herb marshes. Inturn, they eventually are invaded by shrubs and become scrub communities.Closely related types-Bluejoint-herb communities are similar to bluejoint meadowsbut have a substantial component of broad-leaved herbs or, rarely, other graminoidsor ferns. They also may be similar to some bluejoint-shrub stands but lack a significantshrub component. Some mesic forb herbaceous communities may containbluejoint but as a nondominant. flymus spp. and various midgrasses may be presentin some bluejoint herb communities but are less abundant than they are in theelymus or midgrass communities.Photographs-Mitchell and Evans 1966, figure 1.168