Aerial Detection Survey Data Disclaimer: Forest Health Protection (FHP) and its partners strive to maintain an accurate Aerial Detection Survey (ADS) Dataset, but due to the conditions under which the data are collected, FHP and its partners shall not be held responsible for missing or inaccurate data. ADS are not intended to replace more specific information. An accuracy assessment has not been done for this dataset; however, ground checks are completed in accordance with local and national guidelines http://www.fs.fed.us/foresthealth/aviation/qualityassurance.shtml. Maps and data may be updated without notice. Please cite "USDA Forest Service, R5 Forest Health Protection" as the source of this data in maps and publications.

Note for 2023: Areas in the 2023 dataset were calculated using the International Acre. Previous years' ADS data had been calculated using the now deprecated (December 2022) U.S. Survey Acre. For more information please visit https://www.federalregister.gov/documents/2020/10/05/2020-21902/deprecation-of-the-united-states-us-survey-foot

Users need to exercise caution regarding the spatial accuracy of these data due to the subjective nature of aerial sketchmapping and the varying scales of source materials. Comparison with other datasets for the same area from other time periods may be inaccurate due to inconsistencies resulting from rounding of decimal coordinates during conversion, changes in mapping conventions over time, change in assignment of damage casual agent, and type of data collection. Any products (hardcopy or electronic) using these data sets shall clearly indicate their source. If the user has modified the data in any way, they are obligated to describe the modifications on all products. The user specifically agrees not to misrepresent these data sets, nor to imply that changes made were approved by the USDA Forest Service. ***Related to TPA: The national aerial survey support group has decided that “Percent of Forested Area Affected” class is preferable to legacy TPA estimates and starting in 2017, R5 switched to this methodology. Every effort has been made at the Regional level to make this new protocol compatible with legacy standards. However the data structure is now inherently different and making new data directly comparable is a challenge. Please contact: jeffrey.moore@usda.gov for additional information and assistance. These changes are an effort to improve the accuracy in these cases. Some of the confounding factors are a) the inter-mixing of several year's worth of mortality, which makes it hard to see the newly killed trees in among the previous years’ dead; b) the need to draw very large polygons, which tend to be more heterogeneous (more inclusions of non-host and non-forest areas), which make it necessary to not only estimate the number of dead trees in a forest context, but also to make mental adjustment of how much of these large polygons is non-type; c) the recent bark beetle events were at an unprecedented scale and intensity beyond the experience of most any of our observers. ****Related to Polygon Issues During Outbreaks: ADS polygons during outbreaks (such as the mountain pine beetle outbreak in the west) are larger both because the areas of contiguous mortality are larger and also because the observers are only able to record a limited number of polygons given the flight speed. When there are a large number of mortality groups being observed, the observers must include multiple groups of mortality in a single polygon to keep up. This tends to include more areas of non-mortality host, non-host types, and non-forested areas(the areas between the individual groups of red trees). The USDA Forest Service makes no warranty, expressed or implied, including the warranties of merchantability and fitness for a particular purpose, nor assumes any legal liability or responsibility for the accuracy, reliability, completeness or utility of these geospatial data, or for the improper or incorrect use of these geospatial data. These geospatial data and related maps or graphics are not legal documents and are not intended to be used as such. The data and maps may not be used to determine title, ownership, legal descriptions or boundaries, legal jurisdiction, or restrictions that may be in place on either public or private land. Natural hazards may or may not be depicted on the data and maps, and land users should exercise due caution. The data are dynamic and may change over time. The user is responsible to verify the limitations of the geospatial data and to use the data accordingly.