Lost Bear Timber Sale EA - Attachment B 



October 8, 2002 552 



TO: DAVE MARSH, Forester, Clearwater Unit 



CRAIG NELSON, Forester, Clearwater Unit 

 STEVE WALLACE, Unit Manager, Clearwater Unit 

 GARY FRANK, Supervisor, Watershed Management Section 

 RENEE HANNA, Hydrologist/Soil Scientist, SWLO 



FROM: JEFF COLLINS, Soil Scientist 



RE: LOST BEAR TIMBER SALE Sec. 14 & 36, T14N, R14W 



Attached is a revised report on soils on Lost-Bear project area. 



Soil concerns and potential issues to be considered: 



* Equipment operations during timber harvest on wet sites or sensitive soils can result in soil rutting, 

 compaction, displacement and erosion. Long- term soil productivity can be reduced depending on area 

 and degree of physical effects, amount and distribution of course woody debris retained for nutrient 

 cycling. 



* Adequate road drainage, proper construction and reconstruction according to BMP's and maintenance 

 needs on existing roads. 



* Noxious weed spread and encroachment on native plant communities associated with ground 

 disturbance, road construction/ reconstruction, and traffic by trucks and people recreating. 



EXISTING ENVIRONMENT Geology & Soils 



The sale area is located on moderate to steep mountain sideslopes with mainly rocky residual soils de- 

 rived from belt argillites and quartzites. Granitic bedrock occurs on the east side of section 14. There are 

 no especially unusual or unique geologic features in the sale area. There are no known unstable slopes 

 in the harvest area. Three suitable gravel/borrowl sources were noted in the sale area: 1 )an existing 

 borrow site in section 14, and 2) a potential borrow sites in section 36 from the new road construction 

 planned or 3) by widening existing road in east half of section 36. Where gravel is needed it, should be 

 supplied by the contractor from a suitable source. 



SECTION 14, T14N, R14W 



Soils on the west side of the section are mainly Winkler series sandy loam topsoils over very gravelly 

 sandy loam subsoils, which are well drained and droughty. These soils have an early and long season of 

 use. Primary soil concern is potential displacement of shallow surface soils. Erosivity is moderate to low 

 and material quality is good for road construction. Primary soils concerns are avoiding displacement of 

 shallow surface soils dunng skidding and slash disposal. This site is well suited to tractor operations on 

 slopes up to 45% 



Soils on the east side of section 14 include Ambrandt, Ovando and Elkner gravelly sandy loams derived 

 from granitics. Topsoils are typically 4-6 inches loam with some intermittent volcanic ash surface (mainly 

 on north aspects). These are some of the highest productivity soils within the proposed harvest area 

 These soils are more erosive and than the Winkler soils and are subject to displacement from equipment 

 operations Main soil concerns are potential rutting, displacement and erosion, especially on slopes over 

 40%. The complex terrain on the granitics forms numerous small ridges and draws that limit skid trail 

 locations. 



Lower slopes and draws include small areas of Bignell soils on moderate slopes of 15-35%. Bignell soils 

 have gravelly loam topsoils over deep gravelly clay loam subsoils and are well-drained, but remain wet 



