Restoring complexity to industrially managed timberlands: the Mill Creek Interim Management Recommendations and early restoration thinning treatments.

The Mill Creek Property was a commercial timberland acquired by the State of California to protect and restore local and regional ecological values and provide opportunities for compatible recreation. Interim Management Recommendations (IMR) were developed to guide protection, restoration, and public access of the Property until the California Department of Parks and Recreation (DPR) develops a General Plan. Using existing data as well as public and professional input, the IMR planning process identified management alternatives for forest restoration and other priority issues. Recommendations were based on spatial analysis of potential risks and benefits to resources. The IMR identified 5,680 hectares (14,000 acres) of overly dense young coniferous stands needing restorative thinning to accelerate the development of late-successional forest characteristics and avoid the unnatural growth trajectories established by plantation–style forest management. Using public and private funds, a pilot project was designed and implemented to experimentally thin approximately 41 hectares (100 acres). A variable density thinning (VDT) prescription was used to lower tree densities and is expected to accelerate growth, increase stand level heterogeneity and adjust tree species composition. Tree growth, wildlife habitat and wildlife use are monitored against unthinned control areas using permanent plots. Results will inform the development of future prescriptions designed to restore late-successional forest characteristics.