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DNRC Headquarters
1539 Eleventh Ave. Helena, MT 59601
Phone: (406) 444-2074 | Fax: (406) 444-2684
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Aerial Survey Maps and GIS Data


Aerial detection survey (ADS) is the process of mapping the occurrence and extent of forest pests, primarily bark beetles and defoliators, from fixed-wing aircraft.  The ADS program in Montana is a part of the U.S. Forest Service, Forest Health Protection program. 

The ADS process is paraphrased here from the 2016 Montana conditions report:

  • Aerial detection survey provides a “big picture” assessment of forest damage and change.
  • It allows surveys of large areas of forest land in a relatively short time.
  • Damage, as evidenced by recently-killed or defoliated trees, is recorded on either a digital sketch-map or paper map by an aerial observer in a light plane.
  • The observer assigns a code for the agent that likely caused the damage; this is inferred from the size and species of tree as well as the foliage color and damage pattern.
  • Areas burned by wildfire are not surveyed until the third year following a fire, as it can be difficult to distinguish mortality caused by fire from that caused by insect or disease activity.
  • The amount of mortality from root disease, dwarf mistletoe, and white pine blister rust are greatly underestimated with ADS because symptoms from these agents can be difficult and, in some instances, impossible to identify from the air.


2016 ADS Survey for Montana

Previous ADS Surveys for Montana