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19 <br />Steepness of Slope Rating <br />In many cases, slope steepness is one of the most important <br />factors limiting forest management activities or making them more <br />costly. Table 7 lists slope classes for Orange County in order of <br />increasing limitation for forest management. A rating of 1.00 is <br />assigned to the slope class (0 -6 %) with the least limitation to <br />management. Ratings assigned to other slope classes are relative to <br />the lowest slope class (15 -45 %) in terms of cost management. <br />As an example, the 0 -15 percent slope class is rated 1.00. The <br />15 -45 percent slope class is rated 0.50, because it costs <br />approximately 50 percent more to harvest trees on such slopes (1.00 <br />x 0.50 = 0.50, and 1.00 - 0.50 = 0.50). Since there is roughly a <br />"straight line" relationship between harvest cost and slope, the 6- <br />15 percent slope class is rated as 0.75. <br />Table 7 <br />Steepness of Slope Rating <br />------------------------------------------------------ <br />Slope % Rating <br />1 z <br />0 -6 1.00 <br />6 -15 0.75 <br />15 -45 0.50 <br />Source: Soil Survey of Orange County, NC <br />USDA, Soil Conservation Service <br />Appendix E lists Orange County soils from the flatest to the <br />steepest according to slope. The list served as the basis for the <br />slope ranges identified in Table 7 above. <br />Soil Limitations Rating <br />In this rating, soil features, other than slope, that limit <br />management activities or make them more costly are evaluated. Soil <br />characteristics that limit forest management activities were <br />derived using a system of ordination symbols which identify <br />woodland suitability. <br />The first part of the ordination symbol, a. number, indicates <br />the potent--"!---.,. productivity of the soils for. important trees. The <br />number 1 indicates very high productivity; 2, high; 3, moderately <br />high; 4, moderate; and 5, low. The second part of the symbol, a <br />letter, indicates the major kind of soil limitation. For Orange <br />County, the limitations are few but important. The letter w <br />indicates excessive water in or on the soil; c, clay in the upper <br />part of the soil; and r, steep slopes. The letter o indicates <br />insignificant limitations or restrictions. <br />Ordination symbols for Orange County soils are shown in <br />Appendix E. The major limitations, other than slope, for forest <br />land use are identified below. <br />