Federal Register / Vol. 56, No. 157 / Wednesday. August 14. 1991 / Proposed Rules 40467 



If analyzing vegetation units, meander 

 through the unit making visual estimates 

 of the percent area covered for each 

 species in the herb, shrub, sapling, 

 woody vine, and tree strata; 

 alternatively, for the tree stratum 

 determine basal area using the Bitterlich 

 method (see Dilworth and Bell 1978; 

 Avery and Burkart 1983). Then: 



(1) Within each stratum determine 

 and record the cover class of each 

 species and its corresponding midpoint 

 The cover classes (and midpoints) are 

 T= <1% (none); 1=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). 



(2) Rank the species v«thin each 

 stratum according to their midpoints. 



(Note: If two or more species have the 

 same midpoints and the same or essentially 

 the same recorded percent areal cover, rank 

 them equal: use absolute areal cover values 

 as a tie-breaker only if they are obviously 

 different.) 



(3) Simi the midpoint values of all 

 species within each stratiun. 



(4) Multiply the total midpoint values 

 for each stratum by 50 percent. 



(Note: This number represents the 

 dominance threshold number and is used to 

 determine dominant species.) 



(5) Compile the cumulative total of the 

 ranked species in each stratum until 50 

 percent of the sum of the midpoints (i.e., 

 the dominance threshold number), for 

 the herb, woody vine, shrub, sapling, 

 and tree strata (or alternatively basal 

 area for trees) is immediately exceeded. 

 All species coritributing areal cover or 

 basal area to the 50 percent threshold 

 are considered dominants, plus any 

 additional species representing 20 

 percent or more of the total cover class 

 midpoint values for each stratum or the 

 basal area for tree stratum. 



(Note: If the threshold is reached by two or 

 more equally ranked species, consider them 

 all dominants, along virith any higher ranked 

 species. If all species are equally ranked, 

 consider them all dominants.) 



(6) Record all dominant species on an 

 appropriate data sheet and Ust indicator 

 status of each. Proceed to Step 9. 



If using the transect approach, sample 

 vegetation in each strattmi (e.g., tree, 

 shrub, herb, etc.) occiuring in the sample 

 plots using the foUovmig quadrant sizes: 

 (1) A 5-foot radius for bryophytes and 

 herbs, and (2) a 30-foot radius for trees, 

 saplings, shrubs, and woody vines. Plot 

 size and shape may be changed as 

 necessary to meet site conditions, but be 

 sure that it is sufBcient to adequately 

 characterize the plant commimity. 

 Determine dominate species for each 

 stratum by estimating one or more of the 

 following as appropriate: (1) Relative 



basal area (trees); (2) areal cover (trees, 

 saplings, shrubs, herbs, woody vines, 

 and bryophytes); or (3) stem density 

 (shrubs, saplings, herbs, and woody 

 vines). When estimating areal cover, use 

 cover classes T (trace) through 7 and use 

 the midpoints of the cover classes to 

 determine dominants, see substeps 1 

 through 5 above. All plants covering the 

 plot and representative of the plant 

 commimity under evaluation should be 

 counted in the cover estimate; plants 

 overhanging from adjacent plant 

 commimities should not be coimted. 

 Record all dominant species on an 

 appropriate data sheet and list the 

 indicator status of each. Proceed to Step 

 9. 



Step 9. Determine whether the 

 hydrophytic vegetation criterion is met. 

 Areas that do not m6et the hydrophytic 

 vegetation criterion, and that do not 

 meet one of the descriptions of 

 exceptions, usually are not wetlands. If 

 the hydrophytic vegetation criterion is 

 met. Proceed to Step 10 after completing 

 the vegetation section of the data sheet. 



Step 10. Determine whether the hydric 

 soil criterion is met. Locate the 

 observation area on a county soil siu^ey 

 map, if possible, and determine the soil 

 map unit delineation for the area. Using 

 a soil auger, probe, or spade, make a 

 hole at least 18 inches deep at the 

 representative location in each plant 

 commimity type. Examine soil 

 characteristics and compare if possible 

 to soil descriptions in the county soil 

 survey report or classify to Subgroup 

 follovmig "Soil Taxonomy" (often 

 requires digging a deeper hole), or look 

 for regional indicators of significant soil 

 saturation. If soil has been plowed or 

 otherv«se altered, which may have 

 eliminated these indicators, proceed to 

 the section on disturbed areas. Complete 

 the soils section on the appropriate data 

 sheet and proceed to Step 11 if 

 conditions satisfy the hydric soil 

 criterion. Areas having soils that do not 

 meet the hydric soil criterion are 

 nonwetiands. 



(Caution: Become familiar with hydric soils 

 that do not possess good hydric field 

 indicators, such as red parent materied soils, 

 some sandy soils, and some floodplain soils, 

 so that these hydric soils are not 

 misidentified as nonhydric soils; see the 

 "Atypical Hydric Soils discussion.) 



Step 11. Determine whether the 

 wetland hydrology criterion is met 

 Record observations and complete the 

 hydrology section on the appropriate 

 data form. If the wetland hydrology 

 criterion is met proceed to Step 12. If 

 the wetland hydrology criterion is not 

 met the area is nonweUand. 



[Caution: Certain exceptions to the three 

 criteria may not meet the hydrology criterion; 

 see discussion of these areas.) 



Step 12. Make the weUand 

 determination for the plant community 

 or vegetation unit Examine the data 

 forms for the plant community (sample 

 plot) or vegetation unit When the 

 community or unit meets the 

 hydrophytic vegetation, hydric soil, and 

 weUand hydrology criteria, the area is 

 considered weUand. Complete the 

 summary data sheet proceed to Step 13 

 when continuing to sample the transect ■ 

 or other vegetation units, or to Step 14 

 when determining a boundary between 

 wetland and nonweUand plant 

 communities or units. 



[Note: Before going on. double check all 

 data sheets to ensure that the forms are 

 completed properly.) 



Step 13. Sample other plant 

 communities along the transect or other 

 vegetation units. Repeat Steps 6 through 

 12 for all remaining plant communities 

 along the transect if following transect 

 approach, or repeat Steps 7 through 12 

 at the next vegetation unit When 

 sampling is completed for this transect 

 proceed to Step 14, or when sampling is 

 completed for all vegetation units, 

 proceed to Step 15. 



Step 14. Determine the weUand- 

 nonweUand boundary point along the 

 transect. When the transect contains 

 both weUand and nonweUand plant 

 communities, then a boundary must be 

 established. Proceed along the transect 

 from the weUand plot toward the 

 nonweUand plot. Look for the 

 occurrence of UPL and FACU species, 

 the appearance of nonhydric soU types, 

 subUe changes in hydrologic indicators, 

 and/or slight changes in topography. 

 When such features are noted, look 

 closely for evidence of weUand 

 hydrology in the soU and locate the 

 wetland boundary (i.e., the point at 

 which the weUand hydrology criterion is 

 no longer met). Establish sample plots 

 on each side of Uie boundary (e.g., 

 within 50 feet) and repeat Steps 8 

 through 12. If existing plots are within a 

 reasonable distance, additional plots 

 may not be necessary, but always 

 identify the features that were used to 

 identify the boundary. Data sheets 

 should be completed for each new plot 

 Mark the position of the weUand 

 boundary point on the base map or 

 photo and stake or flag the boundary in 

 the field, as necessary. Continue along 

 the transect until the boundary points 

 between aU weUand and nonweUand 

 plots have been established. 



(Caution: In areas vtrith a high intersperslon 

 of wetland and nonwetland plant 



