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Forthofer, J. M. 2007. Modeling wind in complex terrain for use in fire spread prediction. Fort Collins, CO: Colorado State University, Thesis. (528 KB; 123 pages) [ Forthofer 2007 ]

The Caspar Creek watershed, in coastal Northern California, features many gullies in its tributary valleys that deliver sediment directly into the perennial channel network. These gullies may help explain rates of sediment delivery in the watershed.Sediment production from gullies responds to pulses in runoff. Resistant elements observed at headcut lips appear to slow the rate of headcut retreat temporarily until the elements are undercut. Headcut retreat occurs at both a gradual rate (0-15 cm yr-1) in most headcuts and at a high rate (>1 m yr-1) in a few. Banks, like headcuts, can fail sud...

Road decommissioning work has been studied in the South Fork Caspar Creek experimental watershed since 1998, when a 4.6 km (2.8 mi) segment of Forest Road 600 was decommissioned. A total of 26 watercourse crossings and eight cross-drain relief culverts were removed, while an additional eight minor crossings remained untreated. A detailed time study documented costs associated with the different treatments implemented at these sites. Gully measurements were made after one and three over-wintering periods. Additional measurements consisted of a longitudinal profile with three to five cross-secti...

Unpaved forest roads are recognized as being the primary source of anthropogenic sediment that is delivered to stream channels in managed forested watersheds in the western United States. Research studies, sediment budgets, and agency monitoring projects in California have shown that road-stream crossings and road segments that drain to crossings are high-risk sites for sediment input. In particular, older "legacy" roads and crossings that pre-date current forest practice rules can be sources of chronic and episodic sediment delivery. Because many California streams provide habitat for listed ...

We developed a predictive model of soil temperature maxima during burning of masticated fuels. The model was well explained by three factors: soil moisture, soil depth, and fuel heat load. Soil texture, in contrast, was unrelated to the temperature profiles, suggesting a single model is applicable for all tested soils (pumice sand, loam, clay). Soil moisture as low as 20% by volume was sufficient to quench soil heating and inhibit the progression of lethal soil temperatures below the surface inch. Thus, burning of masticated fuels when soils are moist is recommended to avoid damaging roots and...

Mastication may moderate fire behavior by reducing fuel bed depth, but high loadings of surface fuels can still result in substantial mortality of residual trees when burned. Even so, it is possible to reduce masticated fuel loads using prescribed fire. In this study, the high soil moisture levels at the time of the burns limited heat penetration into the soil. Under these conditions, the major cause of initial mortality appeared to be due to crown scorch, which can be mitigated by adjusting firing techniques, and burning when air temperature is low.

Ecologically sound fuels management actions are often desired, but ecological and fuels-based management goals may not be synchronous. The MAST treatment generated heavy loadings of woody fuel on the surface, which may inhibit the germination and establishment of shrubs, but also reduced richness of native understory species. Fuel treatments where the masticated material was partially removed by incorporation into the soil or prescribed burning, resulted in greater understory species establishment, but also resulted in higher abundance of fire-stimulated shrubs. The MAST/RX treatment removed t...