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Individual Highlight

Bringing the rain after the fire

Photo of Forest Service visiting scientists Sergio Prats and Maruxa Malvar (standing) from the University of Aveiro in Portugal prepare for a rainfall simulation. The three rainfall simulator legs and metal plot frame are visible in the foreground. The black matting around the plot was used to capture rainsplash, one component of the erosion within the plot. The tent was used to protect the simulation from wind. Forest Service visiting scientists Sergio Prats and Maruxa Malvar (standing) from the University of Aveiro in Portugal prepare for a rainfall simulation. The three rainfall simulator legs and metal plot frame are visible in the foreground. The black matting around the plot was used to capture rainsplash, one component of the erosion within the plot. The tent was used to protect the simulation from wind. Snapshot : With not a cloud in the sky and temperatures soring into the triple digits, watershed scientists brought a cooling respite to the California interior, even if it was only within one 2-foot-by-2-foot patch at a time. Forest Service researchers used a portable rainfall simulator in mid-June to measure runoff and erosion on soils impacted by post-fire salvage logging operations near Middletown, Calif. The research also tested the effectiveness of adding logging debris, or slash, as an erosion mitigation technique. This technique combined with the process-level results will help improve best-management practices used in post-fire logging operations.

Principal Investigators(s) :
Wagenbrenner, Joe 
Research Location : Valley Fire, Boggs Mountain Demonstration State Forest, Lake County, CA
Research Station : Pacific Southwest Research Station (PSW)
Year : 2017
Highlight ID : 1331

Summary

Post-fire logging adds a disturbance to forests affected by wildfire, but the effects of this added disturbance on soils and streams is not clear. Other studies raise questions about whether compaction or the change in surface cover from logging equipment leads to higher erosion rates locally. Forest Service scientists used rainfall simulations to compare the impact of compaction and surface cover on soil erosion rates. Rainfall simulations allow us to test very specific soil conditions under a controlled environment, thereby reducing the natural variability that occurs in soils and with natural rainfall. The simulations were done in severely burned areas with compaction and surface cover treatments: compacted by logging equipment; compacted with added logging residue, or slash; no compaction plus added slash; and, no compaction or added slash (control). Results indicate the amount of soil moved by rain drops was lower in the compacted soil than in the uncompacted controls. Conversely, the total amount of runoff and erosion from the small plots was greater in the compacted areas than in the controls. Erosion rates were lower in the slash-covered plots regardless of compaction condition. These findings suggest that multiple erosion mechanisms are active at this small scale and that the surface cover may be more important than compaction. These results will help the agency develop alternative best management practices for post-fire logging.

Forest Service Partners

External Partners

 
  • CALFIRE