USFS AERIAL DETECTION SURVEY: 2022 SUMMARY REPORT (R5 California Tree Mortality)
Information below is based on data recorded and shared by the USDA Forest Service, R5 State & Private Forestry, Aerial Detection Survey (ADS) program. Surveys are conducted to provide annual estimates of tree mortality and damage and depict broad mortality trends. Most of California’s forested areas were surveyed in 2022.
Highlights from this year’s survey:
• Total tree mortality increased significantly both in acres affected and particularly in estimated trees killed from 2021. Average severity of mortality was also significantly higher.
• Mortality consisted primarily of true fir which comprised over 77% of the total and was the largest tally ever recorded by R5 ADS. Mortality was particularly severe and widespread in the central Sierra Nevada Range.
• Mortality was particularly severe and widespread in the north interior in several conifer species where drought conditions were most exceptional.
• Mortality attributed to mountain pine beetle (Dendroctonus ponderosae) remained steady with an estimated 380,000 dead trees across 44,000 acres in 2021 to approximately 390,000 dead trees across 40,000 acres in 2022. Within this group, whitebark pine accounted for most of the mortality occurring throughout its range.
• Douglas-fir mortality (not attributed to damage by bears) increased most dramatically. However, mortality in 2021 was relatively small. 2022 Mortality was common throughout the host range but was particularly concentrated north and west of the Redding area.
• Pinyon pine mortality attributed to Ips sp. increased from an estimated 60,000 dead trees across 8,400 acres in 2021 to ~220,000 dead trees across 16,000 acres in 2022 mostly in the White Mountains of far eastern CA.
• Incense cedar mortality was quite common and is underrepresented by aerial survey based on field reports as these trees were typically smaller size class and thus hard to see from a distance.
• Tanoak mortality attributed to sudden oak death (Phytophthora ramorum) decreased substantially since dry spring weather inhibits the spread of this invasive disease.
• Oak mortality attributed to goldspotted oak borer (Agrilus auroguttatus) decreased significantly and was again concentrated primarily in and around the Palomar Ranger District, Cleveland National Forest in San Diego County.
• Oak discoloration, early leaf-drop, possible dieback and mortality was common throughout interior areas of the state. Actual mortality is difficult to detect from a distance, but significant oak mortality is possible over large areas.
