Skip to content

Mountain Pine Beetle and Western Spruce Budworm Infestations Challenge Montana Forest Owners

By Gary Ellingson, Northwest Management, Inc.

Over the past 3-4 years forest landowners in central and southwestern Montana have faced the largest known Mountain Pine Beetle (MPB) epidemic on record. The results have been devastating for those directly affected. Lodgepole pine stands with average diameters greater than 6 inches have suffered greater than 90% mortality. Ponderosa pine stands in many areas have 90% of trees greater than 8 inches dead or infested. Elsewhere ponderosa stands typically have 40-70% mortality. Viewed from local highways many mountain sides in the area are a vast sea of red-needled dead trees.

To make matters worse an extensive western spruce budworm infestation is impacting Douglas-fir, sub alpine fir and spruce forests throughout the region. Maintaining the health of these tree species is even more important in mixed stands where all pine species are either dead or infested with MPB.

At the same time landowners are faced with an economic recession and the weakest log market in decades. These are the toughest of times for landowners and Northwest Management, Inc. (NMI) foresters with decades of experience. However, there have been some successful outcomes as the result of applied forest management. Here are some of the observations NMI foresters have made.

In regards to Mountain Pine Beetle:

  • Ponderosa pine stands maintained at a basal area of less than 80 sq. feet per acre are suffering significantly less mortality from MPB than non-treated or dense stands.
  • Pro-active management such as sanitation and salvage of dead and green beetle infested trees prior to the next years beetle flight (late June or early July) is reducing mortality rates the following year in ponderosa pine stands.
  • Proper application of certified insecticides during late spring-early summer by a qualified contractor to non-infested pine trees works well as a preventative action. Cost averages about $25 per tree. Trees must be sprayed to the point the bark is saturated on all sides to a height of 45 feet. This takes proper equipment, a good applicator, and the correct insecticide. Beware of individuals marketing products that can save infested trees, its simply not possible.
  • Proper placement of verbenone pouches will reduce infestation rates in many pine stands. The NMI office in Helena distributed over 11,000 verbenone pouches to area landowners. Cost is about $18 per tree or $325 per acre.
  • Proper utilization and marketing of wood products is especially important to minimize costs and increase potential returns resulting from sanitation/salvage harvests. Beware that markets are especially volatile at this time.
  • Landowners with infested forests, who waited too long, missed potential opportunities to market higher value sawlogs. Much of this material must know be marketed as pulpwood as a result of blue stain and decreased log quality.
  • Slash management is a key issue and must be thoroughly addressed in all harvest operations.
  • Planning for post infestation activities such as reforestation, weed control and erosion control should occur as early as possible.
  • Wildfire hazard mitigation work takes on added significance in beetle killed pine stands especially near home sites, driveways, and public roads.

In regards to western spruce budworm:

  • Aerial application of Bt (bacillus thuringensis) had worked extremely well to control western spruce budworm damage. NMI coordinated spraying on over 4,000 acres of private forest land in Montana this year and has witnessed excellent results.
  • Proper timing is critical to the success of aerial spraying programs.
  • Maintaining an open forest stand structure helps to lessen the impacts of western spruce budworm.

The impacts of these infestations have impacted landowners in so many different ways. However, there is plenty of evidence that proper forest management can lessen damage associated with forest insect infestations. Professional foresters can assist in even the direst circumstances by designing environmentally sound treatments that are conducted in the most cost effective manner possible. Good planning and coordination is especially important during these difficult times.

Share this post

Share on facebook
Share on twitter
Share on linkedin
Share on pinterest
Share on print
Share on email