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SPECIFICATION - 391 - 1 <br />NATURAL RESOURCES CONSERVATION SERVICE <br />CONSERVATION PRACTICE SPECIFICATION <br />RIPARIAN FOREST BUFFER <br />(Acre) <br />CODE 391 <br />GENERAL SPECIFICATION <br />Procedures, technical details and other information listed below provide additional guidance for <br />carrying out selected components of the named practice. This material is referenced from the <br />conservation practice standard for riparian forest buffer and supplements the requirements and <br />considerations listed therein. <br />SPECIFICATIONS APPLICABLE TO ALL PURPOSES <br />All buffers will consist of a Zone 1 that begins at the normal bankfull or high water line, or at the top of <br />the bank, and extends a minimum distance of 15 feet, measured horizontally on a line perpendicular <br />to the water body. <br />Occasional removal of some tree and shrub products such as high value trees is permitted in Zone 1 <br />provided the intended purpose is not compromised by the loss of vegetation or harvesting <br />disturbance. A minimum of 25 percent canopy cover of woody vegetation will be maintained in Zone <br />1. Felling and skidding of trees shall be directed away from the water course or body. Skidding will <br />be done in a manner to prevent ephemeral channels perpendicular to the stream. <br />PLANT SPACING <br />Initial plant-to-plant spacing for trees and shrubs depend on their potential height at 20 years of age. <br />Heights may be estimated on: 1) performance of the individual species (or comparable species) in <br />nearby areas or similar sites, or 2) predetermined and documented heights using Table 6 from <br />Colorado Plant Materials Technical Note #59 Plant Suitability and Seeding Rates for Conservation_ <br />Plantings in Colorado. The following are recommended spacings for various canopy closures: <br />Table 1 <br />Tree & Shrub Spacing based on Crown Width <br />and Percent Canopy Closure Desired <br /> <br />25% Canop y/Crown Closure 50% Cano py/Crown Closure <br />Avg. Crown Width-ft. Trees-shrubs/Ac Spacing- <br />ft. Avg. Crown Width-ft. Trees-shrubs/Ac Spacing- <br />ft. <br />25 22.18 44.31 25 44.37 31.33 <br />20 34.66 35.45 20 69.33 25.07 <br />18 42.79 31.90 18 85.59 22.56 <br />15 61.62 26.59 15 123.25 18.80 <br />12 96.29 21.27 12 192.58 15.04 <br />10 138.66 17.72 10 277.31 12.53 <br />8 216.65 14.18 8 433.30 10.03 <br />6 385.15 10.63 6 770.31 7.52 <br />5 554.62 8.86 5 1109.24 6.27 <br />NRCS, CO <br />AUGUST, 2006