Valley Oak Seedling Growth Associated with Selected Grass Species

Abstract

Valley oak (Quercus lobata Née) has exhibited inadequate regeneration since the last century. Seedlings become established, but few develop into saplings. We hypothesized that the invasion of alien annual grasses into native perennial grasslands has increased oak seedling mortality by decreasing soil moisture availability. We conducted greenhouse experiments to test if the alien annual grass Avena fatua L. and the native perennial grass Stipa pulchra Hitchc. differentially effect soil moisture and valley oak seedling growth. Results showed that valley oak seedlings in the A. fatua treatments grew significantly smaller than seedlings in the S. pulchra treatments. In addition, valley oak seedling growth showed a positive correlation with soil moisture during the growing season. The results suggest that the introduction of alien annual grasses has reduced valley oak seedling growth and survivorship by limiting soil moisture availability.

Parent Publication

• Proceedings of the symposium on oak woodlands and hardwood rangeland management; October 31 - November 2, 1990; Davis, California

Citation

Danielsen, Karen C.; Halvorson, William L. 1991. Valley Oak Seedling Growth Associated with Selected Grass Species. In: Standiford, Richard B., tech. coord. 1991. Proceedings of the symposium on oak woodlands and hardwood rangeland management; October 31 - November 2, 1990; Davis, California. Gen. Tech. Rep. PSW-GTR-126. Berkeley, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; p. 9-13