Effects of prescribed burning on two perennial bunchgrasses in the Bald Hills of Redwood National Park

Coastal grasslands in Redwood National Park, known locally as the Bald Hills, are dominated by introduced species. The most dominant and invasive is tall oatgrass, Arrhenatherum elatius. Increasing in cover and distribution rapidly since 1985, it has invaded many areas formerly dominated by native grass species. Park managers wish to develop prescribed burn strategies to inhibit tall oatgrass while not adversely affecting present levels of native species, in particular California oatgrass, Danthonia californica. In 1990 an investigation was undertaken to evaluate and compare the effects of spring and fall prescribed burning on tall oatgrass and California oatgrass. Results indicate that tall oatgrass is inhibited from further spread by both spring and fall burning. California oatgrass is severely reduced from spring burning and slightly reduced from fall burning. Spring burning is not an option for conducting prescribed burns because of the severe effect on the native California oatgrass. Fall burning may be more effective in controlling tall oatgrass if combined with other techniques. Further investigations are recommended utilizing these techniques.