Post-fire remediation actions, specifically hydraulic mulching and seeding, are costly to implement on the large areas affected by wildfires and are not effective in controlling erosion.
Point of View:
There is the perception that after a wildfire, erosion and sediment control measures are implemented over the entire burn area, making remediation questionable not only from a ecological point of view, but from an economic perspective as well. The reality is that especially in California, where urban development encroaches on wilderness area, most fire-affected areas are left to regenerate on their own through natural processes. In the 1993 Southern California Fires, of the approximate 186,000 acres that burned, less than one percent, or 1,860 acres were treated with aggressive erosion and sediment control measures. Again, in the San Diego County Fires of 2003 and 2007 less than two percent of the fire-affected areas were treated. Simple economics dictates that reclamation efforts focus on those areas where the impacts from post-fire hazards are the greatest... and that’s in the urban interface.
Application of hydraulic measures after fires can, in fact, be somewhat more expensive than normal construction-related hydraulic applications due to two factors: 1. Treatment areas are typically steep slopes in the urban interface which are difficult to access except by hose; and, 2. The depth of ash typically encountered on post-burn soils can at times increase the typical application rate of hydraulic matrix (e.g., 3,000 lbs per acre) by as much as 33% (4,000 lbs per acre) as the dry nature of the ash combines with the hydraulic mixture.
It is generally accepted that vegetation provides slope stability and reduces soil erosion, and that there are many different ways to re-vegetate burned areas... including letting the area regenerate on its own. But in lieu of scientific evidence to support either opposing viewpoints on re-vegetation methodology and approaches, many of the current arguments for and/or against post-fire remediation are non-scientific, non-technical and revolve around political, social and economic considerations.