Susceptibility of trees to SPB attack increases with age.
Mature and overmature trees usually have slower radial growth, flat-topped
crowns, and sparse foliage. These trees seldom respond to intermediate
cuttings and should be replaced with the most resistant host species or a
species mix suited to the area.
Many overmature pine stands throughout the South are being
intentionally preserved for ecological, wildlife, or aesthetic reasons. These
stands are extremely susceptible to attack and should be monitored regularly
to detect the buildup of SPB populations early, when remedial action can
save the pine component.
These overmature trees with their lower vigor are just not
able to fight off the beetle. Landowners should harvest their pine
according to their management goals, but always keep in mind that if these
older trees are attacked the opportunity to collect on an economic return
from their investment rapidly decreases.