Behind the headlines: Dave Leatherman: How bad are the beetles?

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Q. How many acres (or trees) in Colorado are threatened by spruce beetle?

A. We have about 4.4 million acres of forest in Colorado categorized as "spruce-fir," meaning it contains at least some spruce (spruce and fir almost always grow together in mixed forest). That number is from the 1983 Forest Inventory and Analysis data collected by the U.S. Forest Service. Spruce beetle is only a threat to older spruce, so probably a few million acres are susceptible.

Q. How many acres (or trees) in Colorado are threatened by mountain pine beetle?

A. About 60 percent of the 3 million acres of Ponderosa pine and 3 million acres of lodgepole pine are susceptible, or about 3.6 million acres total.

Q. How many acres have those types of beetles affected already?

A. According to the 2002 aerial surveys, spruce beetles affected 211,000 acres statewide, 177,000 of which was in Routt County. Mountain pine beetles affected 349,500 acres statewide, 3,900 of which was in Routt County.

Q. How many acres are being killed by other beetles?

A. We are seeing major problems from Ips beetles statewide because of the drought. The major problem is with piñon pine, of which more than 1 million acres are dead to some degree. The Douglas-fir beetle killed about 22,000 trees in 2002. Other bark beetles include the fir engraver in white fir, and various beetles that affect Douglas-fir, elm and fruit trees. Western pine beetle is killing tens of thousands of mature Ponderosa pines in Southwestern Colorado. Almost all of these are tied to the statewide drought to some degree. Lack of moisture is the problem. The beetles are the messengers.

Q. Are beetles killing a lot of trees now across the West?

A. Yes, the entire West is witnessing bark-beetle epidemics. British Columbia has perhaps the worst mountain pine beetle epidemic. Major losses to spruce beetle are occurring in British Columbia also, as well as Alaska and areas of many western states.

Q. Where are the worst spots for spruce and mountain pine beetle in Colorado now?

A. Routt County has the worst of the spruce beetle, although there are smaller pockets all down the central spine of Colorado's mountains into New Mexico. Mountain pine beetle is the worst in Grand County, from South Park to Buena Vista, the Vail Valley, and to a lesser degree, along U.S. Highway 285 in Jefferson and Park counties and the upper Poudre Canyon.

Q. How do Steamboat and Northwest Colorado compare to those hot spots?

A. Routt County has the worst of the spruce beetle. I would not rate the mountain pine beetle situation among the state's worst, although it could continue to grow, similar to what we are seeing to the south in Grand County.

Q. What can we expect to see in the state's landscape during the next few decades?

A. If the drought continues, if the forests continue to stay old and dense, and if there is a continued reluctance to manage forests via thinning and judicious harvests, bark beetles are the logical answer, along with fires, to change the forests back to something younger and thinner.

Bark beetle outbreaks typically do not kill everything, and there will be trees left when epidemics subside. But they certainly are capable of killing large numbers of trees over large landscapes.

Unless we are willing to live with the outcome of such natural phenomena, we need to actively manage forests for which the inherent cost of preventing or minimizing large-scale insect epidemics makes sense.

We need to decide which forests to leave to natural processes and which require human intervention, and begin the work of trying to have these types of forests co-exist, often in proximity to one another.

In short, we need to decide how to have our cake and eat it, too: fires, beetles or log trucks.

Q. How do dead trees relate to fire?

A. Dead spruce trees certainly can burn, but fire has not historically been a major factor at high elevations. However, the drought that extends up to timberline has shown as recently as 2002 in the Mount Zirkel Complex Fire that fires can burn in conjunction with a spruce beetle outbreak. Dead trees provide fuel for fire but probably do not represent a major threat in terms of increased risk of ignition.

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