Figure 6- High priority spot in plantation
(North Carolina Forest Service).
Figure 7- Low priority spot in sparse
||If spots are numerous, assign a priority for
ground checking to each SPB spot reported. List at the time of observation
both the estimate of spot size and the ground check priority next to each
spot location on your map or photo. Ground crews will then know which spots
to check immediately and which ones they may visit as time permits. For
your own reference or to aid new observers, prepare a priority table for
your survey area. On it, list conditions to look for in evaluating spots
from the air. Table 1 is an example of a priority table for aerial observers.
Experience has shown that SPB infestations in mature sawtimber stands
(see fig. 1) or dense pine plantations (fig. 6) are most apt to spread
unless controlled. You should assign these spots a higher ground check
priority than SPB spots in sparse pine stands (fig. 7) or in areas containing
more hardwoods than pines.
Many forest managers prefer commercial salvage of infested pines for
beetle control. But the spot must be accessible and have enough timber
volume to justify salvage efforts. A logger can afford to build roads
when a large volume of timber is involved; a small volume may be worth
salvaging only if it is near an existing road. If salvage is the only
means of control used in your area, you should give a low ground check
priority to small, inaccessible spots.
The land use objective may also influence the priority you assign a spot.
A SPB spot in a residential or recreational area (see fig. 3), for example,
may require immediate action. But a spot in a wilderness area or in a
remote, noncommercial forest may well be given a low ground check priority.
Upon completion of each detection flight, give ground crews a fist of
the spots requiring ground checking. For each spot, include plotted position,
estimate of spot size, and ground check priority. Ground crews then have
all the information they need to systematically handle large numbers of