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B. Cumulative Effects 



In areas of checkerboard ownership (usually alternate Forest Service and 

 private), independent land use planning may cause simultaneous disturbance 

 of large areas within the same drainage, creating more impacts than if 

 only one ownership were involved. Federal land use plans and environ- 

 mental impact statements rarely treat cumulative impacts of si Ivi cultural 

 practices on public and private lands. Practices on private lands are 

 normally not coordinated with practices on public lands (except for co- 

 operative road construction programs). 



Si Ivi cultural practices coupled with other land uses such as grazing often 

 lead to additional water quality impacts. Throughout our survey, it was 

 apparent that land uses other than timber management contributed to water 

 quality problems. Often it is impossible to distinguish the source of water 

 quality problems in areas of multiple land uses. (Another complicating 

 factor is the role played by natural processes contributing to the system, 

 i.e., slumps, bank instability, etc.). 



C. Critical Areas 



Si Ivi cultural practices acceptable to one area may not be acceptable in 

 another area because of differences in the capability of each area to 

 absorb impacts. Such differences may result from the natural limitations 

 and hazards of an area, the historical land use activities in an area, or 

 a combination of these factors. The following listing describes several 

 parameters that should be considered when planning silvicultural activites. 



