Baseline - A line, generally a highway, unimproved road, or some other evident feature, from which sam- 

 pling transects extend into a site for which a jurisdictional wedand determination is to be made. 



Bench mark - A fixed, more or less permanent reference point or object of known elevation; the U.S. Geo- 

 logical Survey (USGS) installs brass caps in bridge abutments or otherwise permanently sets bench marks 

 at convenient locations nationwide; the elevations on these marks are referenced to the National Geodetic 

 Vertical Datum (NGVD), also commonly known as mean sea level (MSL); locations of these bench marks 

 on USGS topographic maps are shown as small triangles; since the marks are sometimes destroyed by 

 construction or vandalism, the existence of any bench mark should be field verified before planning work 

 which relies on a particular reference point; the USGS or local state surveyors office can provide informa- 

 tion on the existence, exact location and exact elevation of bench marks. 



Biennial - An event that occurs at 2-year intervals. 



Bog - A shrub peatiand dominated by ericaceous shrubs (Family Ericaceae), sedges, and peat moss 

 (Sphagnum spp.) and usually having a saturated water regime or a forested peatiand dominatedjjy ever- 

 green trees (usually spruces and firs) and/or larch (Lxirix laricina). 



Boreal region - The geographical area just below the arctic tundra and usually characterized by evergreen 

 forests. 



Bryophytes - A major taxonomic group of nonvascular plants comprised of true liverworts, homed liver- 

 worts, and mosses. 



Buried soil - Soil covered by an alluvial, loessal, or other deposit (including manmade), usually to a depth 

 greater than the thickness of the solum. 



Buttressed - The swollen or enlarged bases of trees developed in response to conditions of prolonged in- 

 undation. 



Capillary fringe - A zone immediately above the water table in which water is drawn upward from the wa- 

 ter table by capillary action. 



Chemical reduction - Any process by which one compound or ion acts as an electron donor, in such cases, 

 the valence state of the electron donor is decreased. 



Chroma - The relative purity or saturation of a color, intensity of distinctive hue as related to grayness; one 

 of the three variables of color. 



Comprehensive wetiand determination - A type of wetiand determination that is based on the strongest 

 possible evidence, requiring the collection of quantitative data for all three wetiand identification criteria. 



Concretion - A localized concentration of chemical compounds (e.g., calcium carbonate and iron oxide) in 

 the form of a grain or nodule of varying size, shape, hardness, and color, concretions of significance in 

 hydric soils are usually iron oxides and manganese oxides occurring at or near the soil surface, which have 

 developed under conditions of fluctuating water tables. 



Contour - An imaginary line of constant elevation on the ground surface; the corresponding line on a map 

 is called a "contour line". 



Cover class - A category into which plant species would fit based upon their percent areal cover, the cover 

 classes used (midpoints in parentheses) are T = <1% cover (0), I = 1-5% (3.0), 2 = 6-15% (10.5), 3 = 

 16-25% (20.5), 4 = 26-50% (38.0), 5 = 51-75% (63.0), 6 = 76-95% (85.5), 7 = 96-100% (98.0). 



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