BEsT MANAGEMENT PRACTICEs HANDbooK - Tahoe BMP

Table 8-16: Advantages and Disadvantages of Shorezone Vegetation BMPsADVANTAGES• Complement, or become an element of thebackshore and/or SEZ.• Provide more appealing vistas for humansand more attractive habitat for wildlife.• May become self-sustaining, once properlyestablished.• Strengthens the structure and stability ofsoils.• Can add floristic variety and diversity to theexisting or original plantings.• Provides corridors and refugia that supportmovement of organisms through thebackshore.• Creates or enhances additional wildlifehabitat.• Provides scenic improvements andscreening of structures.DISADVANTAGES• Takes a minimum of 1-3 years to establish.• Often requires mechanical soil stabilizationmeasures to protect the initial investment.• Success is most assured in moderateerosional settings.• Requires regular monitoring andmaintenance.• May create obstructions that must beaccommodated during construction,increasing costs.• Requires additional planning andcommunication with contractors andinspectors.8.8.3 DESIGN CONSIDERATIONS AND PLANNINGRetain and protect shorezone vegetation wherever possible. Saving desirabletrees, shrubs, forbs, and grasses can provide a combination of erosion control,aesthetic value, shade, screening, wildlife habitat, and windbreak protectionthat will be desirable after construction. When planning development of a site,try to site structures between vegetation patches and avoid the area within thedrip-line or root perimeter of the trees. Avoid unnecessary grubbing andclearing of vegetation and avoid disturbing vegetation on steep slopes and othersensitive areas. Use construction boundary fencing and careful traffic control atthe construction site. Trees need to be protected from mechanical damage tothe trunks, compaction of the soil in the root zone, and grade changes thatraise or lower the ground at the base of the trunk near the root collar. Criteriauseful in determining which vegetation to save includes: location, species, size,age, vigor, aesthetic value, wind firmness, and growing space needed.8.8.4 INSTALLATIONTo protect vegetation against mechanical injury and soil compaction aroundtheir root zone, install temporary fencing or other barriers around vegetationpatches and along the driplines of trees. In the Lake Tahoe Region, the treedripline is determined by calculating the diameter of the tree in inches andconverting that number into feet measured from the base of the trunkextending outward to form a protective perimeter. If properly installed, snowfencing is adequate in protecting trees that are close to driveways or withinbuilding sites. Never nail boards, wire, or rope to a tree. Instead, wrapprotective wood staves around the bole and trunk of a tree that is close tofrequent mechanical activity. Never place fill material next to the trunk of atree designated to be retained or over shrubs, forbs, grasses and low growingCHAPTER 8: Shorezone Protective Structures and BMPsTRPA BMP Handbook8.8 Shorezone Vegetation 2012Page 8-56