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I • commonly expected for a relationship between cover and precipitation over a relatively <br />wide range ofx values. <br />The plots and equations derived for the relationship between January-July precipitation <br />and total herbaceous production at both the Osgood sand reference azea and the <br />reclamation azeas were moderately well correlated. Figures 3 and 4 depict the <br />relationships graphically and reveal the third order polynomials representing the best-fit <br />with the data. Correlation coefficients aze nearly equal for both data sets (0.7451 for the <br />reference azea and 0.7396 for all reclamation areas). The shape of the curves suggests <br />that total herbaceous production would decrease with cumulative January-July <br />precipitation in the 10.0-inch range after a general increase from lower cumulative <br />precipitation levels and a steep increase with greater precipitation levels. While this <br />represents the best-fit relationship with the data, this relationship does not appear to be <br />borne out empirically in the field. <br />September-Tuly <br />In hopes of obtaining a better predictive relationship between precipitation and the <br />vegetation parameters, a different precipitation regime was investigated. It was <br />hypothesized that precipitation accumulation from the end of the growing season through <br />the eazly portion of the next yeazs growing season might produce a closer relationship <br />between precipitation and the vegetation parameters. The hypothesis was that <br />• precipitation could be utilized by the vegetation directly through uptake at the end of the <br />growing season and stored in below ground biomass for use eazly in the next growing <br />season. Further, precipitation could percolate into the porous sands of the area and <br />provide a moisture pool for use by plants eazly in the next growing season, particularly <br />benefiting the warm season component of all vegetative communities. To test this <br />relationship, a precipitation regime consisting of the cumulative precipitation value from <br />September through July of the following yeaz was calculated for each of the yeazs during <br />which sampling occurred. This was referred to as September-July precipitation. As with <br />the January-July precipitation regime, best-fit equations were derived for the Osgood sand <br />reference azea and the reclamation azeas for total vegetation cover and total herbaceous <br />production. The results aze graphically found in Figures 5-8. <br />In the Osgood sand reference azea, the best-fit derived equation and plot reveal excellent <br />correlation between September-July precipitation and total vegetation cover at the <br />Osgood sand reference azea (Figure 5). The correlation coefficient is higher (R2= 0.9477) <br />than that found in the best-fit relationship derived from January-July precipitation. As with <br />the predictive equation derived from the January-July precipitation data the form of the <br />equation is a third order polynomial generally indicating an increase in total vegetation <br />cover over increasing precipitation with a corresponding decrease in the rate of increase in <br />cover with increasing precipitation over the range of sample values. <br />. The relationship between September-July precipitation and total vegetation cover at all <br />reclamation azeas (Figure 6) was equivalent to that derived from the January-July <br />_~ <br />