Beetles At Work!


photo looking donw at stand of dead (brown) spruce photo of dead (brown) spruce trees

The photos above were taken August 2013 in the Cochetopa area of the Gunnison National Forest (south and east of the town of Gunnison) showing the extensive tree mortality from the beetle outbreaks. It takes about two years for the spruce beetle to complete its life cycle.


Image of adult Spruce beetle image of inner bark of tree section

An adult spruce beetle bores into the bark of a spruce (left). During the first phase of infestation the trees look debarked. During the second year, needles turn yellow or orange (fade) and eventually drop to the ground during wind or rain storms (photo S. Munsen).

image of eggs Image- of channels in tree bark for eggs

Spruce beetle eggs and a larval gallery (photos W. Ciesla and  E Holsten).

The beetles have been relentlessly advancing over the past decade, increasing the acreage of infested stands within the Rio Grande, San Juan and Gunnison National Forest from a few thousand to over half a million acres. The landscape south and east of Gunnison, bordering the Rio Grande National Forest is one of the hardest hit areas on the GMUG National Forest. 

The spruce beetle (Dendroctonus rufipennis), is the most significant natural mortality agent of mature spruce. Spruce beetle outbreaks cause extensive tree mortality and modify stand structure by reducing the average tree diameter, height, and stand density.  Residual trees are small and slow growing but eventually become dominant. The resilience of currently healthy stands can be improved by thinning and removing the largest trees, and leaving a diversity of sizes and ages of spruce.

The GMUG National Forest is working on the Spruce Beetle epidemic as well as the decline of Aspen stands. The Spruce Beetle Epidemic and Aspen Decline Management Response (SBEADMR) Project has been initiated with a team of specialists working on the Environmental Impact Statement (EIS) for the project.

Spruce Beetle Progression 2003 to 2013

Annual Aerial Forest Health Survey

Aerial detection surveys of tree killing or damaging insects and diseases are conducted annually over Colorado’s forest lands. This is a cooperative effort between the US Forest Service and the Colorado State Forest Service. Annual surveys only include forest damage that is visible from the air. Each year, 28 million acres are surveyed by 7 trained federal and state surveyors.

The US Forest Service is taking action to address the bark beetle infestations. The Rocky Mountain Region is focused on increasing the pace and scale of active forest management across Colorado. Each National Forest is stepping up forest treatments, and many are working collaboratively to strategically plan and apply work to the areas that need it most. The US Forest Service now has four 10-year stewardship contracts to remove dead trees to restore forests and increase their resiliency. The US Forest Service has also awarded several short-term stewardship contracts aimed at improving forest health and adding to local economies.

One example is the recently operational Gypsum biomass plant. The plant converts wood chips from beetle-killed trees into enough electricity to run the plant and pump an additional 10 megawatts into the Holy Cross Energy Facility, which powers approximately 55,000 customers in Eagle, Pitkin, Garfield, Gunnison and Mesa counties. Much of the wood the plant will process will come from beetle-killed trees from the White River National Forest.

Forestry agencies have a key role in sustaining forest ecosystems, which provide many benefits to the people of Colorado and many surrounding states. Whether progress is measured by the reduction of large-scale wildfires, timber harvested or number of forest acres treated; the outcome is the same: healthy and resilient forests, and the protection of forested watersheds.

While the US Forest Service takes action on National Forest lands, the CSFS works with private landowners to help them meet their management objectives to achieve healthy forests. The agency  has released a new quick guide on the spruce beetle, and has held numerous educational public meetings about the beetle for citizens in Chaffee, Custer, Fremont, Huerfano, Lake, Las Animas, Pueblo and Saguache counties.

For the most updated information on forest health conditions in the Rocky Mountain Region, visit

For information directed at private landowners to help manage for healthier forests, visit

Beyond Bark Beetles

Our Future Forests have much to offer. View a selection of short videos on forest regeneration, fire, recreation, and more...