The forests in the San Bernardino Mountains and the
Peninsular Ranges are seriously drought stressed. In addition, some have diseases (dwarf mistletoe, annosus root disease) which also cause severe stress. Stressed trees can't produce enough resin to protect against pathogens. Examples of these include the California flatheaded borer, mountain pine beetle, red turpentine beetle, Jeffrey-pine beetle and western pine bark beetle. The fir engraver attacks fir trees while the Ips beetle is a scavenger that attacks the tops of trees, along with slash and seriously distressed trees.
Trees in the San Bernardinos are subject to drought, air pollution, and complexes of pests, not just beetles. Deciduous species are affected the same as the coniferous species; black oaks there are suffering from drought stress and also defoliation by the fruit-tree leafroller.
(Entomologist Dr. Laura Merrill, personal communication) |
Piper Navajo remote sensing aircraft 
