Long-term performance of minimum-input oak restoration plantings

Abstract

Starting in 1989, we used minimum-input methods to restore native oaks to parts of their former ranges in Vacaville, California. Each restoration site was analyzed, and only those inputs deemed necessary to overcome expected limiting factors for oak establishment were used. We avoided unnecessary inputs that added to cost and could have unintended negative consequences. All projects were direct-seeded by volunteers using locally collected acorns of valley oak (Quercus lobata) and other native oaks. Other inputs included mulch and protection from herbivores (cattle, voles) or mowing crews. Plantings received sporadic maintenance after planting. None of the plantings were irrigated or fertilized. Growth rates and survival show spatial variation at all locations. Multiple project locations now have stands of oaks that have been established at very low cost, validating the minimum input approach. Some very low input plantings had high mortality due to unanticipated impacts from fire and vole outbreaks that greatly exceeded levels previously observed. Lessons learned from the long-term performance of these plantings can be applied in an adaptive management system to accomplish low cost, ecologically sound oak restoration projects in other locations.

Parent Publication

• Proceedings of the seventh California oak symposium: managing oak woodlands in a dynamic world

Citation

Bernhardt, Elizabeth; Swiecki, Tedmund J. 2015. Long-term performance of minimum-input oak restoration plantings. In: Standiford, Richard B.; Purcell, Kathryn L., tech. cords. Proceedings of the seventh California oak symposium: managing oak woodlands in a dynamic world. Gen. Tech. Rep. PSW-GTR-251. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 397-406.