The current dense forest structure and high fuel loading in many forests may increase the risk of damaging wildfires, but may also affect disturbance agents such as bark beetles and tree pathogens. Treatments such as thinning, burning, or thinning and burning, may decrease the risk of some disturbance agents and increase the risk of others. A secondary objective of the Fire/Fire Surrogate study is to evaluate the incidence and effects of forest insects and diseases in each of these treatments.

~Bark beetle-caused tree mortality

~Percent of trees infested by aggressive and non-aggressive bark beetles

~Predation of bark beetles by cavity dependent wildlife such as woodpeckers

~Course woody debris habitat availability

~Root disease occurrence and frequency

~Dwarf mistletoe occurrence and severity

~Treatment-related damage of host trees

~Thinning and burning effects on natural enemies of bark beetles (e.g., clerid beetles, predatory flies, and parasitic wasps)

~Thinning and burning effects on bark beetles (e.g., mountain pine beetle, Douglas-fir beetle, red turpentine beetle, and pine engraver)

~Effects of hazard reduction treatments on tree pathogens (e.g., dwarf mistletoe, root diseases, and stains-particularly those transmitted by bark beetles)

~Effects of hazard reduction treatments on folivorous pest species (e.g., pine butterflies, casebearers, pitch moths, and sawflies)

Relationships among bark beetles and woodpeckers in FFS treatments
- with Jennifer Woolf, Scott Mills and Don Christian (Wildlife Biology, University of Montana)

~Some bark beetle species, such as pine engravers, Douglas-fir beetles, and red turpentine beetles, increased after spring burning.

~Mountain pine beetle did not increase in response to treatments.

~Thinning had no significant effect on bark beetle attacks or tree kills in the first two seasons after treatment.

~Fire treatments had little effect on natural enemies of bark beetles, except for a small increase in clerid beetles immediately after burning.

~Thinning increased the abundance of predatory flies and parasitoids. Presence of predatory beetles also increased in the second summer after treatment.

~Fire treatments increased ponderosa pine defenses (resin flow), primarily in the late summer.

Bugwood

Forest Health Protection

Fire Effects Information Database

Dr. Diana Six webpage