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PresentLv t.`.e re are t +a r.acLons, ar ap'f CJJ C!1d Y. JC ]FC CO:]JarISO i .:ontrot [h.ir are used. :hey are the "refe .. ~~ area" sop roach and [he "tanerol area" app roar h. leLe rence Areas Tlfe refe re ^,ce area approach essuc~_s chat coop artian arras (refe re ate ..raasl ad}a<rnc or near [o [he areas ro ae r't s[urhrd (o re a!r.e areas) cart ba !dentitied ch. r_ directly represent the premine areas Sncn Sr fa re sad .c ;er sirtcnv,. The reference area sop rna~_h as used in Glo ra do, Hev 9e xtw and ;;rah depends on findin¢ areas gen- erally from L-5 acres in si c~c that have the sa:.e vegeta tl ce expressions as the prerf~~ areas. Ii these areas are not diffcrr n[ from the premine areas as dete ~Sned by staciscical hyp tic E.esis testing, then they a:e Xe ne rally acce Dta 6lr as reference areas. When testy ; for recr,;r to t[on success, the reference areas and reels lard areas are both sampled. If the scans o[ [he pa ranc[e rs of concern on the [vo areas can't he shown co be dlf fete n[, then success is Sndi to [ed. Control Areas With the control area approach, as used Sn Wyoming, [he standard obtained frao [he compari- son area (control area) is zdj usted to refle c[ the ratio of [he control area values to the pre- mine area values. IC isn't necessary [o test [he equi vale^cy of [he control areas and the pro ci ne areas at the time the control areas are selected. Instead, [he baseline samollnq of the pre mire and ton[rol areas 1s used [o de [e rm inc the relacion- ehlp be[weon [he two areas as a ratio or pit cent •(Wyoming Depar[me nt of _n vi tonne oral Oua lity, 1981). If, for e:ca aple, a~prc mi ne area has 85: ~of Che production measured on the control area, [hen of ter mining and reclama [ion, the re clai-ed area 1s exile c[cd to have 85X or more of [he pro- duc[fon otcu rrl ng on the undisturbed control area. Historic Record Concept The se rood general concept is the historic record. I[ assumes [hat [he premine ve get a[Ion tondltf tins 6ef ore wining di re t[ly retire sea[ what a hould exist on postnining reclaimed areas. The gul de lines for [he Stale of U[ah, for example, suggest tulle c[in~ data from [he premine area for at leas[ one year. The data must be co lie c[ed In a year when [he effective pre cipt[a[lon 1s a[ least 90% of the normal pr.,•cin itacton (Utah Division of 011, Cas and `lining, 1931). These me asureiaunts would [hen 6e used to de[e rani ne the Dome rival re vc ye [scion scanda rds. t:ew >!e xlco and Colorado also allow Chc h1s[o rival record •rproac h. As a policy, rev ~(e xl co requires seven years of prealn(ng do [a colic c[lon. Cofo ra do [equi res a s[atls[lcally adequate sa~np lc of prc- mfning sand [[tons (Colorado h!1 Wed Land Re clamor ton Hoard, 1930). Teeh 1 Ou!danc _- Oocur_a n[s :he thlyd~ eral .e ans of dote raining a revepy tattoo success standard is by use o: technt- tal ~n:ldance docuc_ncs. This 15 aLLavud La al! the states ve re vl e~: ad. Lt does not necessa r: lv require s;a ^.da rds hn sed on the ore~ine ve ve cJCtun levc ls. So far, the use of [hLs concepc apps rs to 5` 11 sited [o setting sea nda rds that serve cone sae<l fie po sc =ia Leg :and use. LG has i~rn used La so^=_ !nstan~es tD sec shrJb ;eescabllsh- acnt standards to serve wildlife, e.g. sage grousa, deer and elk. Strengths And Weaknesses of Che Con ce p[s I[ should be noted [ha[ neither Chc compari- son area or his[brf cal ceco rd concept has been shown to be valid. :Jonecheless, cfiese concepts are being widely implemented by regulations, guf de lines, and adninis[ra ti ve po Llcy decisions. Reference Areas The reference area concept assumes relatively small arias (1-5 acres) accurately represent [he Bondi [ions on [he premine areas chrn ugh time. IF [he concept is valid, i[ of re rs a means of au[o- ma[Scally adj uscing the standard Eton year [o year to reflect the iniluunces of climate and other factors on vegetation. In fact, hove ve r, there Ss no tie ar demonstration [hat [he concepc is val ld or tan be pea c[ically applied. (8owards,- I980). We analyzed three years of vc ge Cation da [a Erom reference areas and pre nine areas in nor[h- vest Colorado to assess [he validity o[ the refer- ence area concept. These da [a were obcatned from six reference areas and wo premining vegetation communities at [he end of the graving seasons, 1980-1982. Three reference areas were used tar each of [he two vegetation conmunic ies. the com- parisons were Wade using the averages Eton each Bet of three reference areas. Table 1 eur...~a rites [he results of hypothesis testing at a 90.'. confi- dence level to determine if [here vas a diffe ren:r he cvicen the production on [he reference and pre- mine areas. In f980 and 1932 the refe ru ace areas ve re no[ dLffe re n[ with 907. conf lde ace than [h.: preml ne areas [hey re presented. They, [here-`ore, s a[Ssf led the Colc [ado criteria for acceptance as refe once areas. In 1981, however, the hypothesis testing concluded a dif Eere ace did exist. These results indicate [ha[ Lf an operator tested for success Sn a year I1 ke 1961, :he reclaimed area you ld have [n have greater production than [he pre ml nc area ltse lf. These data Safer that within Chc lln[ts of to tee n[ samp ling [echno logy, Chc reference area concepc as applied is Invalid, at leas[ for Chc pa r[lcular arc as evaluated. I[ should be noted [ha[ to [he [tamp le pre se n[<d, Chc prer.,i ne area values ve re compared agal nst l00% of the -~