Species area curve - The curve on a graph produced when plotting the cumulative number of plant species 

 found in a series of quadrats against the cumulative number or area of those quadrats; it is used to deter- 

 mine the number of quadrats sufficient to adequately survey the herb strauim. 



Spodic horizon - A subsurface layer of soil characterized by the accumulation of aluminum oxides (with or 

 without iron oxides) and organic matter, a diagnostic horizon for Spodosols. 



Stratigraphy - A term referring to the origin, composition, distribution, and succession of geologic strata 

 (layers). 



Stratum - A layer of vegetation used to determine dominant species in a plant community. 



Suborder (soils) - Second highest taxonomic level of the current U.S. soil classification system. 



Substrate - nonsoil. 



Surface water - Water present above the substrate or soil surface. 



Temperate region - The geographic area having a climate that is neither very hot nor very cold. 



Tidal - A situation in which the water level periodically fluctuates due to the action of lunar (moon) and so- 

 lar (sun) forces upon the rotating earth. 



Topography - The configuration of a surface, including its relief and the position of its natural and man- 

 made features. 



Transect - A line on the ground along which sample plots or points are established for collecting vegetation 

 data and in many cases, soil and hydrology data as well. 



Translocation - The transfer of matter from one location to another within the soil. 



Transpiration - The process in plants by which water is released into the gaseous environment (atmos- 

 phere), primarily through stomata. 



Tree - A woody plant 5 inches or greater in diameter at breast height and 20 feet or taller. 



Typical - That which normally, usually, or commonly occurs. 



Ultisols - Highly weathered soils having significantiy more clay in the B-horizon than in the A-horizon and 

 having low base stams; acidic soils common in the Southeast. 



Unconsolidated parent material - Material fix)m which a soil develops. 



Upland - Any area that does not qualify as a wedand because the associated hydrologic regime is not suffi- 

 ciendy wet to elicit development of vegetation, soils, and/or hydrologic characteristics associated with wet- 

 lands. Such areas occurring in floodplains are more appropriately termed nonwetiands. 



Value (soil color) - The relative lightness or intensity of color, approximately a function of the square root 

 of the total amount of light; one of the three variables of color. 



Vascular (plant) - Possessing a well-developed system of conducting tissue to transport water, mineral 

 salts, and foods within the plant. 



Vegetation - The sum total of macrophytes that occupy a given area. 

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