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Mount Rushmore National Memorial Drafting Plans to Fight Bark Beetles


The pine forests that surround Mount Rushmore National Memorial are in danger of being overrun by mountain pine beetles. The beetles -- the adults are black, their offspring grubs can be seen if you look closely -- are about the size of a grain of rice, as the bottom photo shows. One they bore through the outer bark of a pine tree, the beetles chew through the phloem, leaving tell-tale burrows. Top photo by Ed Menard, NPS, bottom photo NPT file photo.

How do you combat a tiny beetle that is killing acres and acres of lodgepole forest that long has served as a gorgeous backdrop to Mount Rushmore National Memorial? That's the puzzling question an interagency team of entomologists and foresters is trying to answer.

Mountain pine beetles are about the size of a grain of rice. Rather innocuous in appearance, when they descend on a forest en mass they have the ability to kill lodgepoles in quick fashion. Now, this plight long has been part of the natural ecosystem of the West. Lodgepoles evolved with these beetles and developed defenses to deal with them -- they can smother them with sticky pitch, and the trees relatively rapidly propagate.

Winter's usually have aided the lodgepoles by sweeping bitterly cold temperatures onto the forests, temperatures of 40 degrees below zero and more that were sufficient to kill the beetles. Unfortunately, warming winters in recent years have displayed few of those numbing cold snaps, and the beetles have flourished. And the results can be seen in the dying, reddish-tinged pine forests that become highly flammable.

In January, officials at Mount Rushmore recognized the severity of their pine beetle problem and canceled this year's Fourth of July fireworks display in a move to prevent forest fires. Now the memorial staff has pulled together specialists from Custer State Park, South Dakota Department of Agriculture - Wildland Fire Suppression Division, South Dakota State University, United States Geological Survey and the U.S. Forest Service to brainstorm an action plan for battling the beetles.

During a meeting last week the group discussed the current condition of the pine beetles in the central Black Hills, identified issues and concerns surrounding the beetle problem, and explored treatment options and resources available to address the outbreak. So far park managers have identified pockets of trees affected by the mountain pine beetle, and have taken action to remove some of them from the park for decontamination.

Because the mountain pine beetle epidemic has the potential to affect some of the memorial's fundamental resources, including the forested setting of the sculpture, old-growth ponderosa pine, and scenic vistas, the park’s management team is considering options to mitigate effects while returning the forest to a more natural, historic and sustainable landscape.

Integrating scientific research information, current condition reports, and experience from area specialists, the memorial’s Rapid Resource Assessment Team has compiled an action plan that combats the mountain pine beetle on several fronts. Included for consideration in the draft plan are steps to prevent infestation of high value trees within visitor use areas that help maintain the visual landscape around the sculpture, measures to seek out and attack mountain pine beetles that have already entered the park, and proactive thinning and buffering of the memorial’s forest against the encroaching mountain pine beetle population. These actions are in concert with projects being carried out by Custer State Park and the Black Hills National Forest to mitigate the mountain pine beetle infestation.

"This level of cooperation among partner land management agencies and experts is critical to helping the National Park Service explore and develop effective methods to keep this infestation from getting out of control within memorial grounds," said memorial Superintendent Gerard Baker. "This landscape has been and continues to be treasured by many cultures over the ages and we have a responsibility to preserve the unique natural resources in the park and the Black Hills.”

Chris Holbeck, who is heading the Rapid Response Action Team, is hopeful the planning sessions will hit upon a plan "to make a difference for this outstanding area, and for the people who love and
respect it."

"Here at the memorial, the landscape, and the sculpture are of local, regional and national significance, and the memorial is small enough in size, that aggressive action on the ground is possible. Indeed some of the actions recommended in the plan could be completed in the first 100 days," said Mr. Holbeck. "The plan will be open to public review and we are very interested in what the public has to say regarding our recommended approach."

The draft plan is expected to be available this week for public review. When it's ready, you'll be able to find it at At that site, if you go choose "Mount Rushmore National Memorial" from the drop-down list you'll be able to find information on the action plan and a place to submit your comments on the proposal. The website is available for public comment until March 15. Copies of the plan will also be available for viewing at the Mount Rushmore Information Center, located at the memorial, until March 15.


Tilting at Windmills.

First I challenge your comment about recent warming causing the spread of the beetle. The average temp data since 1900 in the Black Hills region ( shows no such trend.

For those hoping to attack the beetle - don't get your hopes up. As a resident in the Colorado Rockies where the beetle has proliferated, I can tell you that breaks and thinning have little if any impact. Only annual spraying at $10 a tree has any prophylactic affect. The beetles are winning because the trees are getting old and vulnerable. It is a natural cycle and other than the short period when the dead needles are on the trees, beetle kill trees are actually less vulnerable to fire than a live forest. Save your (our) money and let nature take its course.

I'm not an expert in statistics, but if you apply the LINEST excel function to the data linked in the above comment you actually do get an upward trend, with a slope of approximately 0.0114. Can anyone else duplicate my results?

I'm pretty skeptical too. Most probably lodgepoles will only survive on higher grounds, where there will real winters even in the longer future. Lower parts will get broad leaves. Of course the exchange will take some time, but nature can wait. In about 200 years there will be a great forest again, just no lodgepoles.

Not a trend that is significant enough to alter the impact on beetles. It would have to be more than 10 degrees warmer than the minus forty cited in the article. Furthermore, the trend has been down the last three years at the same time the beetle problem has been moving up.

Anonymous Folks--

Monthly mean temperatures aren't particularly useful for addressing potential factors behind the current density of bark beetles. Beetles are not affected by mean monthly temperatures, but instead by temperatures below a threshold (the -40f in the article) for at least a given duration (1 week is reported). In all the daily max/min temperature data I've looked at (none for MORU), there is at best a very weak correlation between mean monthly temperature and longest duration below a threshold, let alone the probability of a duration > 7 days below a threshold.

In general, mean temperatures (and average precipitation) don't drive biotic responses: extremes do. Saguaros are limited in their northern distribution not by mean winter temperatures, but by the (infrequent) occurrence of 36 hour freezes: they can survive 1 night of moderate freeze (they have lots of solutes in their water), but if they don't thaw during the day the freeze can rupture enough cells to cause tissue damage and death. [We happen to have ~100 years of data and observations for saguaro, including 3 episodes of dieback on the northern edge of the range. Our understanding for most less-charismatic long-lived species is nonexistent.]

Monthly means are equally a problem for understanding potential consequences of climate change. For Joshua Tree NM, summarizing projected changes as a 5f increase in July mean monthly temperatures isn't informative: +5f high with +5f night low has very different consequences than +3f day with +8f night changes, or +7f day +2f night for that matter.

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