California’s forest Resources, 2006-2015: 10-Year forest inventory and analysis report

Brodie, Leslie C.; Palmer, Marin. 2020. California’s forest resources, 2006-2015: Ten-Year Forest Inventory and Analysis report. Gen. Tech. Rep. PNW-GTR-983. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 60 p. Brodie, Leslie C.; Palmer, Marin. 2020. California’s forest resources, 2006-2015: Ten-Year Forest Inventory and Analysis report. Gen. Tech. Rep. PNW-GTR-983. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 60 p. Of California’s almost 100 million ac, about a third are forested (32 million ac). This report, including the accompanying tables, summarizes key findings from the 5,369 Forest Inventory and Analysis (FIA) plots measured in California’s forests during the period 2006-2015. Estimates are provided for forest area, ownership, species composition and distribution, size and age classes, volume, biomass, carbon, dead and downed wood, and understory vegetation. Starting in 2001, plots were measured on a 10-year cycle (10 percent of all plots measured annually). Thus, those plots measured in 2011-2015 represent completion of half of the remeasurement cycle estimates of growth, mortality, and removals from remeasured plots are also included. The U.S. Forest Service manages about half of California’s forested land-48 percent. Fifty-two percent of California’s forests is categorized as timberland (unreserved forest land capable of producing ≥20 ft of wood per acre per year) predominantly consisting of the California mixed-conifer type. The most common forest type on the remaining 48 percent was western oak. Mean annual gross growth was 1.99 billion ft/year. Subtracting harvest removals (21 percent of growth values) and mortality (45 percent of growth values) still resulted in a positive net growth of 673 million ft/year. Of some of the commercially important tree species, damage was present in 17 to 27 percent of the trees, including Douglas-fir (17 percent), white fir (27 percent), ponderosa pine (20 percent), and redwood (17 percent). The two most prevalent nonnative species were both grasses-cheatgrass (estimated 277,000 ac of cover) and ripgut brome (234,000 ac). During the 10-year period, the years with the most forested acres with evidence of fire were 2008 and 2015. FIA plots will continue to be measured as stipulated by the 1998 Farm Bill. By the time the next FIA report for California is issued, a complete remeasurement cycle will have been completed.