Forest Inventory & Analysis (FIA) is a national program of the USDA Forest Service Research and Development Branch.  The FIA program has been in operation since 1930 as the nation’s forest census program, with the official mission to:

“make and keep current a comprehensive inventory and analysis of the present and prospective conditions of and requirements for the renewable resources of the forest and rangelands of the U.S.”

The inventory samples all forested lands in the US, regardless of ownership and management objectives.  Sampling is conducted on a grid of permanent, ground-based plots using national and regional standards that repeatable and provide low errors.  Data collected by the FIA program captures and quantifies tree growth, removal, and mortality well. 


In California, the annual inventory FIA program is managed by the US Forest Service’s Pacific Northwest Research Station Resource Monitoring and Assessment.  The annual FIA inventory in California samples approximately 10% of the FIA plots in California each year, or 100% of the plots over a 10-year period.  The first annual inventory measurement cycle in California was completed in 2010.  The period 2011 – 2020 represented the first cycle of annual inventory re-measurement in California.  In 2021, at the beginning of the second cycle of annual inventory, the FIA program will sample approximately 20% of the FIA plots in California each year, effectively accelerating the rate of FIA data collection conducted in the state two-fold and drawing the re-measurement period down from a 10-year cycle to a 5-year cycle (i.e., temporal intensification).  However, impacts primarily from the Covid-19 pandemic and wildfires in California during the 2020 and 2021 field seasons delayed sampling objectives during these years.  The effect of these delays has extended the completion outlook of the first accelerated cycle to 6-years, rather than five.  Despite this delay, the integrity of the core FIA program is maintained while the state continues to achieve temporal intensification goals. 


Temporal intensification of the FIA re-measurement cycle in California, from a 10-year cycle to a 5-year cycle, provides more frequent estimates of forest conditions, how they are changing, and the drivers of change.  Impacts from climate change, such as drought, insect and disease outbreaks, and wildfire, are becoming more frequent, intense, and larger in scale.  The State also aims to increase the pace and scale of forest restoration.  FIA data on an accelerated re-measurement cycle will help forest managers to assess and respond to the effects of disturbance and management more rapidly and effectively. 

Has the FIA program contacted you to request permission to enter your property to access an FIA plot location? 

Please visit the US Forest Service’s Pacific Northwest Research Station’s FAQ for landowners to learn more: FIA and You: An orientation for forest landowners.