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Aerial Detection Monitoring
Insects and diseases are integral components of forest ecosystems. They play a critical role in shaping forest lands, nutrient recycling, and small-scale disturbance. Disturbances result in changes in the ecosystem function which often means mortality of trees. Tree mortality and other forest damage is detected by annual aerial surveys over forested lands. The primary purpose of the aerial survey is to create sketch maps of areas containing current year conifer and hardwood mortality, defoliation, and other damage. Number of trees and acres with damage are calculated for areas surveyed and reported annually using the methodology described below.
Recent tree mortality and currently active non-mortality damage is sketch mapped on a mobile device by an aerial observer flying in a small fixed-wing aircraft at ≈1000’ AGL searching for visibly dried and discolored foliage, typically yellow to reddish brown. Generally, two observers are onboard the aircraft surveying on opposite sides with about a two-mile swath width for each surveyor.
Drawn polygons are then attributed with the following: a) damage type, mortality or one of several non-lethal damage types (topkill, defoliation, branch flagging, die back or discoloration) b) percentage category of forest area affected, c) affected tree species and d) probable damage-causing agent (root disease, bark beetles, etc.).
Percent of Forest Area Affected is expressed as a severity class: very light 1-3%, light 4-10%, moderate 11-29%, severe 30-50%, and very severe 50%.
Generally, areas with <1% of Forested Area Affected of mortality is considered to have "background" or "normal" levels of mortality and are not usually mapped as polygons during the flight. However, they may be mapped as point data especially if low levels of mortality are indicative of a localized pest-related event. Point data is also broken down into 5 classes: 1 Tree, 2-5 Trees, 6-15 Trees, 16-30 Trees and >30 Trees affected. All other attribute information is identical to polygon data.
Affected tree species is recorded to species level if possible (Sugar Pine and White Fir), or to genus level (pine, fir). Damage occurring on any tree species should be mapped.
Multiple damage types can be listed for each polygon, though more typically overlapping portions of polygons are double or even triple attributed in the overlapping areas. Thus, in areas where two or more tree species affected or two or more damage types occur, the surveyor will typically draw two or more different polygons reflecting the actual location and extent of mortality for each different host or damage type. During editing, the overlapping portions will then be multi-attributed. Likewise, point data can overlap polygon data.
Aerial Survey Results
Final Reports
Data
2023 Aerial Survey Geodatabase (6.9 MB)
Maps
2023 Tree Mortality Map: JPG | Poster
Interim Update Reports
Final Reports
2022 Aerial Survey Infographic
Interim Update Reports
Data
2022 Aerial Survey Geodatabase (8.5 MB)
Maps
Final Reports
ArcGIS Online Resources
Interim Update Reports
- North Interior
- Northeastern California
- North Coast
- Southern Sierras
- Southern California
- Central Coast
National Forest Maps
| Angeles | Cleveland | Eldorado |
| Inyo | Klamath | Lake Tahoe |
| Lassen | Los Padres | Mendocino |
| Modoc | Plumas | San Bernardino |
| Sequoia | Shasta-Trinity | Sierra |
| Six Rivers | Stanislaus | Tahoe |
Data
- 2021 ADS Geodatabase (5 MB download)
Maps & Graphics
Reports
2020 ADS Remote Sensing Report
Area of Interest (AOI) Maps
| Area of Interest | National Forest | County |
| AOI 1 | Cleveland NF | San Diego |
| AOI 2 | San Bernardino NF | Riverside |
| AOI 3 | San Bernardino NF | San Bernardino |
| AOI 4 | Los Padres NF | Ventura Kern |
| AOI 5 | Los Padres NF | Monterey San Luis Obispo |
| AOI 6 | Inyo NF, Sequoia NF | Tulare Inyo |
| AOI 7 | Santa Cruz Santa Clara San Benito Monterey |
|
| AOI 8 | Inyo NF | Mono Madera |
| AOI 9 | Sonoma | |
| AOI 10 | Klamath NF | Siskiyou |
| AOI 11 | Mendocino Sonoma |
|
| AOI 12 | Mendocino | |
| AOI 13 | Mendocino | |
| AOI 14 | Modoc NF | Modoc Lassen |
| AOI 15 | Modoc NF | Modoc |
| AOI 16 | Humboldt Del Norte |
|
| AOI 17 | Six Rivers NF | Del Norte |
| AOI 18 | Eldorado NF | El Dorado Amador |
| AOI 19 | Sierra NF | Madera Mariposa Fresno Inyo |
| AOI 20 | Shasta-Trinity NF | Shasta |
Data
- 2020 Remote Sensing Geodatabase* (1 MB download)
*No aerial survey was flown in CA in 2020. This partial data set was generated using alternate remote sensing techniques. For more details please refer to the 2020 Remote Sensing Final Report.
Maps & Graphics
- 2020 Area of Interest Statewide Map (21 MB download)
Reports
Interim Update Reports
- Central Coast
- Southern California
- Far Eastern California & Part of Western Nevada
- Far Southern Sierra Nevada Range of California
- Northeastern California
- Northern Interior of California
- Northwestern California
National Forest Maps
| Angeles | Cleveland | Eldorado |
| Inyo | Klamath | Lake Tahoe |
| Lassen | Los Padres | Mendocino |
| Modoc | Plumas | San Bernardino |
| Sequoia | Shasta-Trinity | Sierra |
| Six Rivers | Stanislaus | Tahoe |
Data
- 2019 ADS Geodatabase (8 MB download)
- Geolocated Photos for Viewing and Download in Google Earth (.kmz)
Maps & Graphics
- 2019 Tree Mortality Map: PDF | JPG | Poster
- 2014 - 2019 Aerial Detection Surveys Combined: PDF | JPG | Poster
- Aerial Detection Surveys Progression Map: PDF | JPG | Poster
- 2014 - 2019 Animated Tree Mortality Progression Map
- 2019 Highlights Infographic
- Cumulative Mortality Chart
Special Survey: Early Season Drought
Special Survey: Sierra Foothills, Transverse & Coastal Ranges
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