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1 <br />Sitka spruce, Western red cedar, Western hemlock, Pacific dogwood, and Red <br />alder can cause serious disease problems. Disease can become established <br />through damaged limbs, trunks, roots, and freshly cut stumps. Diseased and <br />weakened trees are also susceptible to insect attack. <br />Maintenance Standards <br />Inspect flagged and/or fenced areas regularly to make sure flagging or fencing has not <br />been removed or damaged. If the flagging or fencing has been damaged or visibility <br />reduced, it shall be repaired or replaced immediately and visibility restored. <br />. If tree roots have been exposed or injured, "prune" cleanly with an appropriate prun- <br />ing saw or loppers directly above the damaged roots and recover with native soils. <br />Treatment of sap flowing trees (fir, hemlock, pine, soft maples) is not advised as <br />sap forms a natural healing barrier. <br />BMP C102: Buffer Zones <br />Purpose <br />Creation of an undisturbed area or strip of natural vegetation or an established suitable <br />planting that will provide a living filter to reduce soil erosion and runoff velocities. <br />Conditions of Use <br />Natural buffer zones are used along streams, wetlands and other bodies of water that <br />need protection from erosion and sedimentation. Vegetative buffer zones can be used to <br />protect natural swales and can be incorporated into the natural landscaping of an area. <br />Critical -areas bufferzones should not be used as sediment treatment areas. These <br />areas shall remain completely undisturbed. The local permitting authority may expand <br />the buffer widths temporarily to allow the use of the expanded area for removal of sed- <br />iment. <br />Design and Installation Specifications <br />Preserving natural vegetation or plantings in clumps, blocks, or strips is generally <br />the easiest and most successful method. <br />. Leave all unstable steep slopes in natural vegetation. <br />. Mark clearing limits and keep all equipment and construction debris out of the nat- <br />ural areas and buffer zones. Steel construction fencing is the most effective method <br />in protecting sensitive areas and buffers. Alternatively, wire -backed silt fence on <br />steel posts is marginally effective. Flagging alone is typically not effective. <br />Keep all excavations outside the dripline of trees and shrubs. <br />. Do not push debris or extra soil into the buffer zone area because it will cause <br />2014 Stormwater Management Manual for Westem Washington <br />Volume 11 - Chapter 4 - Page 268 <br />