Northern red-backed vole northern forest and shrubland habitats. They occur in every major forest type in central Alaska. Plant species commonly found in areas occupied by northern red-backed voles include black spruce ("Picea mariana"), white spruce ("P. glauca"), quaking aspen ("Populus tremuloides"), paper birch ("Betula papyrifera"), alder ("Alnus" spp.), willow ("Salix" spp.), mountain cranberry ("Vaccinium vitis-idaea"), blueberry and bilberry ("Vaccinium" spp.), bunchberry ("Cornus canadensis"), and a variety of grasses and forbs. Important fungi, mosses and lichens include truffle ("Endogone fascilulata"), Schreber's moss ("Pleurozium schreberi"), mountain fern moss ("Hylocomium splendens"), sphagnum ("Sphagnum" spp.), and lichens ("Cladonia and Peltigera" spp.). The breeding season of northern
What Is and What Should Never Be and What Should Never Be" was performed live at Led Zeppelin concerts between 1969 and 1973. A live version taken from a performance at the Royal Albert Hall in 1970 can be seen on the "Led Zeppelin DVD". Another was included on disc two of the live triple album "How The West Was Won". Two more versions were included in BBC Sessions. What Is and What Should Never Be "What Is and What Should Never Be" is a song by English rock band Led Zeppelin. It was written by Jimmy Page and Robert Plant and was included as the second