Understanding the Changing Timber Harvest on Private Forestland in California

Over the past 20 years, timber harvest in California has continuously declined, including on privately-owned land. Beyond the decline in timber harvest over this time frame, there have also been other changes in forest management, including changes to the methods used for harvest. Understanding these trends in private forest management in California provides insight into the broader ways in which timberland management can effectively mitigate threats to forest health including fire and disease. In this project, we analyze Timber Harvest Plan (THP) data from CAL FIRE's Forest Practice Timber Harvest Plan GIS database, which includes details about acreage, silvicultural management, region, and yard for every proposed THP, to understand private forest management changes in California from 1997 to 2019. We compare timber harvest practices over time including through analysis across regions, management types, and yard. These analyses identify a significant decrease in timber harvest from 1997 to 2019 while median harvest size has remained nearly constant. Harvest in all regions of California have sharply declined over the time frame, although this decline has been most pronounced in the Sierra region of California. Beyond declining trends in timber harvest, there have also been consistent declines across all regions in California in areas such as evenaged management, intermediate treatments, and the number of unique timber owners submitting THPs every year. Understanding these specific changes in private timber harvest in California over the last 20 years is essential for mitigating threats to fire and disease and promoting healthy and resilient forests.