Table 3-5: Vegetation and Soil Bum Severity for Fish Creek Complex 

 Vegetation Soil Burn 



*Totals vary slightly between tables because of smal differences in GIS analyses. 

 A bum severity map is included in Appendix B: Figure B-1 



Areas of moderate to high bum severity were tested for soil hydrophobicity 

 where soil duff was bumed off and mineral surface soils were subject to 

 erosion. Field observations and tests showed low to moderate soil 

 hydrophobicity on all sites reviewed in September and October therefore 

 infiltration of mnoff will not be as greatly affected as initially predicted. 

 Where hydrophobic conditions occur, natural surface mnoff and erosion will 

 be accelerated, especially in the more severely water repellent areas. The 

 hydrophobic effect is expected to break down with rain and freeze/thaw 

 conditions over years one to three following a fire event. 



Natural erosion rates are expected to be highest on severely bumed sites 

 where the tree canopy was lost and surface litter and duff was incinerated. 

 Naturally high levels of erosion will continue until these sites are revegetated, 

 typically within three to five years. Within the severely bumed areas, the 

 potential for erosion generally increases with slope steepness and will be 

 highest in draws and on existing roads where cutslopes and fillslopes are 

 bumed, poorly vegetated, and have inadequate surface drainage. Slopes on 

 southern aspects in the Deer Creek drainage had lower levels of vegetative 

 cover and may have more elevated levels of erosion compared to those on 

 northerly aspects. Erosion rates are expected to be highest on severely bumed 

 sites the first year following the fire. Relative erosion rates are expected to 

 decline the 2°*^ and 3"^*^ years until a relatively steady rate of erosion is reached 

 and revegetation improves. Eroded sites in draws and gullies could take longer 

 to stabilize. DNRC seeded native grass species in draws in high bum severity 

 to accelerate revegetation. 



In areas of moderate to low bum severity, existing plants are expected to 

 resprout promptly from root crowns and provide some ground cover and 

 erosion control similar to the range of natural fire conditions that would occur 

 historically. It is likely there will be some short-term spurt in plant growth 

 from nutrients released by the fire. On the Sleeping Child bum of 1961, 

 vegetative cover was about 4% in severely bumed area the first year and cover 

 rose to 30% in three years. Vegetative cover was about 10% the year 

 following fire on severely bumed sites within the Sula State Forest in 2001. 



Fish Creek Salvage Environmental Assessment 



3-13 



