Orange County NC Website
Browse       Search
17 <br />III <br />.LAND EVALUATION FOR FOREST LAND <br />The second step in the preparation and use of the LESA system <br />is to determine the quality of land for forest land use. This is <br />done in a manner similar to that used for cropland evaluation. <br />Soils are arrayed in order of importance in forest land groups, and <br />the value of each group relative to another is calculated. <br />RATING SOILS FOR FOREST LAND USE <br />In designing a system for evaluating forest land, soils are <br />rated according to four factors to determine which soils are the <br />best and least suited for forest use. These factors include <br />productivity, value of indicator tree species, steepness of slope, <br />and other soil limitations. <br />Productivity Rating <br />The productivity rating is based on the productivity of the <br />designated indicator tree species for each soil. An indicator <br />species is defined in the SCS National Forestry Manual as "that <br />species which is common in the area and is generally the most <br />productive on the soil in question." <br />The indicator species for each soil is determined from the <br />woodland interpretation tables contained on the Orange County Soil <br />Survey. The indicator species is the first species listed under the <br />column heading "Productivity Potential." The indicator species for <br />Orange County soils are shown in Appendix D. <br />Productivity ratings for each soil are derived from site index <br />values. Site index values are also determined from the woodland <br />interpretation tables in the Soil Survey and refer to the average <br />height an indicator tree species will reach by the age of 50 years. <br />Productivity ratings are determined from the SCS National Forestry <br />Manual according to the indicator tree species and site index value <br />for each soil type. Site index values and productivity ratings for <br />each Orange County soil are shown in Appendix D. <br />Individual productivity ratings are then arranged in as many <br />as 10 groups-_; The range of productivity ratings shown in Table 5 <br />was derived - €rom the SCS National Forestry Manual. and recommended <br />for use in North Carolina. <br />The highest productivity class in the range is rated 1.00. The <br />ratings assigned to the other classes are relative values derived <br />by dividing the average productivity of each class by the highest <br />average productivity. For example, the average for the second class <br />(121 -166) is 144, and it is assigned a rating of 144/166 or 0.87. <br />The average for the third class (79 -120) is 100, and it is assigned <br />a rating of 100/166 or 0.60. <br />