As you drive through Rocky Mountain National Park in Colorado it’s hard not to see the work of the mountain pine beetle. Whether you acknowledge the inevitable cycle of forests or just see it as the reason you had to cut down the once-beautiful pine tree in your front yard, the mountain pine beetle is a fact of life.

Dendroctonus_ponderosaeIt is estimated that most lodgepole pine forests in Colorado will vanish,  real estate values will suffer, and forest fires become more prevalent and harder to control as the pine beetle destroys forests.  Yet, forestry experts and citizens aren’t sure that all the chemicals being sprayed are the right approach.

It seems clear that forest thinning and perhaps supporting healthy trees with deep root watering techniques may make pines more resistant to the beetle.  Forest thinning does have a macro effect. To protect a tree in your backyard, careful cultivation and preventive tree spraying in the months of April, May and June,  can protect high profile trees from being damaged by the infestation.

The mountain beetle is a native species, previously called the Rocky Mountain Pine Beetle. Biologists believe that a succession of mild winters over the past ten years have allowed the beetle to thrive. Typically, the beetle in its larval stage can not survive the consistent 40 degree below zero temperatures that  are typical of winters in the high country of Colorado. However, this decade that cold has failed to materialize allowing a substantial amount of larvae to survive and thrive during the summer months.

Typically the beetle starts flying in late June or July and may continue into September. Although it seems that the beetles has been coming sooner  in areas like the Estes Park Valley, according to local sources.

Pine beetles tend to pick large, weak or diseased trees in denser wooded areas but in an epidemic will target healthy green trees and smaller growth. There is not a consistent promiximity pattern, ie the beetles won’t necessarily attack a similar tree next to their current home.  Once beetles infest a tree there is no practical way to save it.

Part of the power of this pest is the ability for a coordinated attack on a host tree. Once the beetle colony has finished with a tree it will move onto another pine to lay eggs and repeat the cycle. What’s worse is that a colony will grow. If it affected one tree this year it will be able to attack two or even three trees the next year.

You can protect trees on your property. Spraying unaffected pines for the mountain pine beetle in spring when it comes out of its larval stage is the most effective. Beetles will land on the tree and be disrupted by the protected bark. It’s important to remember that as of January 2010, pinyon pines are not as suspectiple as lodgepole, ponderosa pines and other fir trees.

While over spraying in the Colorado high country has been an issue, part of the problem is that tree spraying is being done by unlicensed individuals who have no knowledge of the short, mid and long term effects of pesticide management. You should always hire a company that has a QS (Qualified Pesticide Supervisor) on staff and is approved by the Colorado Dept. of Agriculture to apply pesticides. Cities such as Estes Park and Boulder are writing ordinances which are even more restrictive.

Using different sets of chemicals will reduce the mountain pine beetle’s resistance to the treatment year over year. Avoid spraying low value trees, trees which are very small, or trees which are already dead. In addition, spraying out of season will just kill natural predators and potentially contaminate water.

David Merriman owns Arborscape and is a member of the American Society of Consulting Arborists. Contact us to get a free quote on protecting your pine trees.

Quick Facts About the Mountain Pine Beetle and the Summit County, CO. infestation.  courtesy