Finding Goldilocks: a survey of the factors limiting natural oak recruitment.

View the project final report

Commodities

• Animals: bovine

Practices

• Animal Production: grazing management, rangeland/pasture management, stocking rate
• Education and Training: on-farm/ranch research, workshop, youth education
• Natural Resources/Environment: carbon sequestration, habitat enhancement

The blue oak woodlands of California account for one-third of the grazed land in California and harbor more wildlife than any other ecosystem in California (Borchert et al 1991, Pavlik et al 1991). There is also a clear lack of new oak recruitment (Adams et al 1992, Swiecki and Bernhardt 1997). Recently, Lopez-Sanchez et al. (2014) concluded that “further research on the conditions that would ensure tree regeneration in Californian rangelands is needed in order to determine thresholds of grazing density and timing.” 

We hypothesis that many factors that impact oak recruitment do so as a correlate of grazing pressure. We propose, therefore, that there is a  ‘Goldilocks’ grazing condition where grazing and recruitment can coexist with minimal costly interventions. Our proposal combines rancher knowledge and statistical analysis of comprehensive field surveys to find better recommendations for grazing management to aid natural oak recruitment.

Because of the large scale of blue oak woodlands (3-million hectares: Bollsinger 1988) it is imperative that we study landscape-scale solutions to the problem of recruitment. Much of the blue oak range coincides with cattle grazing and grazing remains one of the few tools that can be applied at a large spatial scale. Ranchers need recommendations for supporting the health of their blue oak woodlands as it provides valuable shade and forage for livestock.

Our field days, technical bulletin, rancher fact sheet will aide ranchers in making land-management decisions that can benefit their oak woodlands and their grazing operation, ensuring another generation of young oaks for the future.We will be reaching out to many large landowners in addition to those listed above, some affiliated with NRCS and some not. While the range and scale of the survey is broad, the technical aspects are simple—making the project feasible for producers.

1. Locate natural oak recruitment microsites on 15-20 ranches
2. Within microsites, sample conditions known to limit oak recruitment
3. Interview landowners regarding ranch management
4. Compile data and analyze for trends
5. Recommended management changes or areas for future research based on results
6. Draft and submit publication
7. Draft and distribute a technical bulletin with a summary of findings for agencies (RCD and NRCS offices) and non-profits (Audubon Ca., The Nature Conservancy).
8. Draft and distribute a fact sheet for landowners and interested groups (California Cattlemen's Association)
9. Host two field days for stakeholders at participating ranches
10. Present findings at the annual conference of the California Association of Resource Conservation Districts and/or at meeting(s) of the California Cattlemen's Association