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annuals, ouch as cereal grains or sterile hybrids, that provide quick cover and then die out to let native vegetation reoccupy the site. Chaparrai.• Chaparral is the shrub-dominated veg- etation type abundant in the low to middle elevation foothills in California and the Southwestern States (Cooper 1922, Keeley and Keeley 1988). Chaparral stands are often located on steep slopes, burn with generally high intensity, and typically develop water- repellent soils. They become candidates for poatfire seeding due to the threat of increased runoff and sediment movement (Ruby 1989). Concern over impacts ofpostfire seedinghas focused on chaparral ecosystems because a specialized annual flora takes advantage of the light, space, and soil nutrients available after fire (Keeley and others 1981, Sweeney 1956). Some of the dominant shrub species regenerate after fire only from seed (Keeley 1991, Sampson 1944). Moat published research on chaparral comes from California (tables 6 and 7). Bruahfields prone to fire and erosion occur at the urban/wildland interface, where growing population centers in lowland valleys have encroached on foot- hillsand steep mountain fronts. The societal impacts of wildfire and subsequent accelerated erosion in California chaparral are enormous, as are the prea- aurea to treat burned hillsides with grass seed to protect life and property (Arndt 1979, Gibbons 1995). Foresters in southern California began seeding burned-over slopes with native shrubs in the 1920'x. After finding that seeded shrubs emerged no earlier than natural regeneration (Department of Forester and Fire Warden 1985), they experimented with intro- duced herbaceous epeciea such as Mediterranean mustards in the 1930's and 1940's (Gleason 1947). Mustards proved to be unpopular weeds with downalope orchardists and suburbanites, so other species were tested, including native and non-native eubshruba and non-native grasses (Department of Forester and Fire Warden 1985). By the late 1940'a annual ryegrase (Latium muitifiorum, also called Italian ryegrasa), a native of temperate Europe and Asia, had became the primary epeciea used For poatfire seeding. Like mus- tard, it was inexpensive, could be broadcast easily from aircraft, was available in large quantities, and its fibrous mot system appeared effective at stabilizing surface soil (Barro and Conaad 1987). The effectiveness of broadcast grass seeding for erosion control on steep chaparral slopes has been questioned (Conrad 1979), but relatively few data an erosion response exist. The first watershed-scale reha- bilitation experiment was set up at the San Dimas Experimental Forest after a wildfire in 1960, includ- ing annual and perennial grass seeding. The fret winter after the fire was one of the driest on record with negligible grass establishment (Corbett and Green 1965). The treatments were reseeded, and the next year seeded grasses did not affect peak etreamflow during four recorded storm events. The high-rate annual grass treatment produced 8 percent grass cover by the time of the last large storm event and resulted in a 16 pement reduction in sediment produc- tion over the season (Krammes and Hill 1963). Con- tour planting of barley, which included hand-hoed rows and fertilization, had the greatest impact on sediment production (Rice and others 1965). Atl seeded treatments had lower cover of native plants than unneeded controls (Corbett and Green 1965). Data collected by the California Department of Forestry showed that ryegrass establishment was typically poor in interioraouthern California and more successful in cooler, northern or coastal locations (Blanford and Gunter 1972). An inverse relationship between ryegraes cover and native herbaceous plant cover was observed, and Blanford and Gunter (1972) felt that more data were needed to properly evaluate the competitive effects of seeded ryegrasa on native herbs. Range improvement studies found that high seeded grass cover could reduce shrub seedling den- sity (Schulz and others 1955). Blanford and Gunter (1972) did not observe major failure of shrub regenera- tion,though noquantitative measurementsweremade. Ageneralnegativerelationehipbetweenryegrasscover and erosion was observed using erosion pine. Blanford and Gunter (1972), like Krammes and Hill (1963) and Rice and others (1965), concluded that poatfire annual grass seeding was an appropriate rehabilitation method because its low cost made occasional seeding failure an acceptable risk. Cover or biomass of native chaparral vegetation, especially herbaceous species, tended to be lower on plots with high ryegrasa cover, both in operationally seeded areas (Keeley and others 1981, Nadkarni and Odion 1986) and on hand-seeded experimental plots (Gautier 1983, Taskey and others 1989). Native plant species richness was lower on plots centaining ryegrasa (Nadkarni and Odion 1956, Taskey and others 1989). Gautier (1983) and Taskey and others (1989) found lower density of shrub seedlings, especially epeciea killed by fire, on needed plots, and warned that long- term chaparral epeciea composition could potentially be affected by grass seeding. Taskey and others (1989) also noted bare areas appearing in seeded plots where ryegrasa died out after 3 years, resultingin lower cover than on unseeded plots. These studies suggested that ryegrase grows at the expense of native vegetation. During a year in which total rainfall was exception- alIy high compared to average, Gautier (1983) mea- sured lees erosion from plots in which ryegraea seed- ing increased total plant cover. On the other hand, Taskey and others (1989) found no effect of ryegrase on first-year postfire erosion with average rainfall and 12 USDA Foresl Service Gan. Tech. Rep. RMRS-GTR-63.2000