Invasion of<br>the bark beetle

Over the past summer, the widespread drought seen in Arizona has been cause for alarm when it comes to the potential for wildfire. Just ask folks in the Mogollon Rim and Prescott areas.

Here’s an example of the type of damage that can be done by bark beetles. The brown trees represent those killed by the insects. (Photo courtesy of Tom DiGomez)

The drought has impacted forests in many other ways as well — from thirsty and hungry wildlife venturing into developed areas to necessary closures during the height of tourism season. Perhaps one of the most damaging fallouts from these dry times involves a tiny culprit known as the bark beetle.

"There’s been beetle infestation in the area, but not on a large scale around Tusayan. There are some areas with small beetle outbreaks," said Jackie Denk, fire information officer for Kaibab National Forest. "Drought conditions are part of the problem."

The other part of the problem involves too many trees in the forest. When times get tough, the trees striving to stay alive deplete available resources and a high mortality rate can often be the result.

"The drought like this pushes them over the edge and makes them vulnerable," Denk said. "Mother Nature will find a way to thin, weather it’s wildfire or tree disease or bark beetles."

With the situation, the Forest Service appears to be headed in the direction of a tree-thinning project.

"We hope to thin out some of these dense stands and help these trees have a natural defense against beetles," Denk said.

Rick Stahn, Tusayan District ranger, agreed.

"We’re kind of in new territory here," Stahn said. "We have larger ponderosa pine stands of trees. When you have certain conditions, they get cranky. The best thing we can do is trying to thin the forest out and reach what we’ve had historically."

Stahn said infested trees on the Tusayan district are scattered, adding that a few will be removed from Ten-X Campground, which is closed for the winter.

The bark beetles have been much more devastating south of the Grand Canyon-Tusayan area in forests around Williams, Flagstaff and Prescott. In those areas, pinyon trees have been hit hard. Out in New Mexico, entire forests of pinyon have gone up because of the insects.

In the Tusayan area, Stahn estimated 5 to 10 percent of trees were being affected.

"There’s quite a bit of mortality around Williams, as there is Flagstaff," said John Anhold, forest entomologist. "There areas are fairly lightly infested compared to Prescott and the Pine-Strawberry area, and Alpine further east in the state."

Anhold said flights were to be conducted over Grand Canyon National Park on Thursday of last week. Results of the fly-over had to be mapped and were not readily available.

"We fly all the forested lands every year," Anhold said. "So we survey and look for fading trees. From that, we make estimates on the numbers of trees that we find (dying) on forests, reservations and park lands."

Anhold did a site visit at Grand Canyon a little more than a month ago and noticed a little bark beetle activity, mainly in pinyon trees.

"I did a lot of driving on the main roads and in that country, it’s tough to see very far unless you get out in there," Anhold said. "Hopefully from the surveys, we’ll have a better idea of what’s going on there."

The bark beetle’s impact on pinyon trees can be seen easily on the drive to Grand Canyon from Flagstaff.

"As you travel from Flagstaff up to the Grand Canyon, you can see a lot of pinyon mortality," Anhold said. "Some areas around Flagstaff we’ve flown and we’ve done some ground surveys and in one particular area, there’s a 90-percent mortality rate in the pinyon. That’s a lot of dead trees."

In the Winona area east of Flagstaff, an estimated 700,000 trees have been killed.

"More than likely, there are a lot of other areas with similar activity going on," Anhold said.

Survey flights were conducted earlier over the North Rim area, and there didn’t appear to be any problems. Anhold believes that the higher moisture and elevation on the North Rim has something to do with the lack of bark beetle problems there.

As Denk indicated, the bark beetle problem is not that much of a surprise. But at the same time, the impact has been noticeable.

"This is a normal part of the ecosystem and sometimes it kills pockets of trees, but not on this massive scale," Denk said. "I think it’s an ongoing problem we’re going to see for several years."

Anhold said the forest needs precipitation.

"This is all being driven by the drought that’s occurred," Anhold said. "As long as the drought continues, we’ll continue to see mortality."

Meetings on bark beetle infestation have occurred in Flagstaff and Williams. Denk said a meeting for Tusayan may occur in the near future.

Comments

Comments are not posted immediately. Submissions must adhere to our Use of Service Terms of Use agreement. Rambling or nonsensical comments may not be posted. Comment submissions may not exceed a 200 word limit, and in order for us to reasonably manage this feature we may limit excessive comment entries.

Use the comment form below to begin a discussion about this content.