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where z3 = mean cover or production for the effected Brea x= = mean cover or production for the reference area t = a t-statistic value, which varies depending on desired level of confidence and sampling size s, = the variance of cover or production for the affected Brea ss = the variance of cover or production 4or the reference area nl = sample size in the effected area ni = sample size in the reference Brea When ~ x~ - x=~ is less then or equal to the other calculated value, the affected area and reference area ere considered comparable for the purpose of evaluating reclamation success. 2.4 Reference Area Sampling Design All sample sites were located by a random process. The southwestern • corner of the reference area served ns the intersection of an x and y coor- dinate system. Positive coordinates were produced by a random number generator. The exact sample point was then paced off by the field ecologist. 2.5 Measurements 2.5.1 Collection end Analysis of Cover Deta Cover was estimated using a point-intercept method along randomly located and oriented transacts (Mueller-Dombois end Ellenberg 19741. Twenty points were sampled along the 50 meter length transact. Paired points were sampled at each 5 meter interval of the transact. Each paired point was 0.75 meter from the transact and perpendicular to the transact. The Siting device was mounted on en adjustable tripod to facili- tate vertical orientation end point stabilization. Fine cross hairs were used in the siting device to provide optimum point definition. At each sample point, the siting device was first directed vertically upward, then vertically downward end the first hit recorded. If woody vegetation (Tree end/or shrub) was intercepted a second or third hit was taken until either herbaceous vegetation or rock, litter, or soil was hit. Vegetation hits were recorded by species. Only first hits were used in calculating percent cover, • -3-