Detailed surveys are typically conducted with either a fixed or rotary wing aircraft, on a map with a scale of either 1:40 000 or 1:50 000. The purpose is to accurately map the type and location of beetle problems so that general treatment strategies can be discussed.
General surveys are usually conducted in a fixed wing aircraft at low flight line
intensities on topographic maps at scales smaller than 1:40 000 (i.e., 1:100 000
or 1:250 000), by either Ministry or Forestry Canada staff. They are conducted
for non-operational purposes (e.g., access or environmental considerations),
where treatments will not be possible. Often these flights are conducted for
forest health factors other than bark beetles, which are not currently being
treated but may receive management in the future. The accuracy of general
overviews is not good enough for most operational purposes, however, such
flights may be sufficient for historical or research purposes. They will also
indicate where detailed surveys are required.
Minimum suggested survey standards
Table 7 in the Forest Health Surveys Guidebook describes the minimum
suggested standards for aerial surveys by forest region. General surveys are
usually conducted at a scale greater than 1:100 000. Flight lines and the location
of the surveys are plotted on these maps.
All forest regions conduct their detailed surveys at either 1:40 000 or 1:50 000 scale. The map base used may be the National Topographic Series, the B.C. Geographic System, or licensee operational maps.
Experience has indicated that colouring both topographic features and susceptible stands can increase the accuracy of polygon placement by 25% and decrease flying costs by up to 20%. Two different methods are currently used to colour maps:
Aerial surveys for bark beetles can begin in the southern regions of the province July 1 (Kamloops, Nelson, Vancouver) and in the northern regions of the province July 30. Attack intensity classes for mapping bark beetles are:
Usually two people are used on survey flights over severely infested areas; one individual can help the other to pick out attack. The best product is achieved when the two sketch maps are compared and amalgamated immediately after the flight. A third person may assist with navigation or recording data such as GPS coordinates or treatment particulars.
Either fixed wing or rotary wing aircraft can be used for detailed flights. If ground work is being directed based on the results of the flights then helicopters are preferred as more accurate GPS coordinates can be obtained. A high winged aircraft with retractable landing gear will give the mappers an unobstructed view of the ground. Bubble type windows are of further value. Both aircraft types should come equipped with a GPS unit.
Flight times should be limited to 5 hours per day to reduce error due to fatigue. Mappers should come equipped with:
Flight lines are usually run parallel over level terrain. Over mountainous terrain flight lines must be adapted to suit the terrain. Flight lines should be placed closer together over moderate or severe infestations.
When planning flight lines consider the following:
It is usually undesirable to conduct both general and detailed surveys over the same ground, unless the general survey can be processed immediately and used to specify where the detailed surveys are to be conducted.
The following sections of this guidebook lay out specific methodologies appropriate for mountain pine beetle, spruce beetle, and Douglas-fir beetle. The appropriate section should be consulted when developing a management program after the species of beetle in question has been identified.
