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Up in flames

Fire threat from beetle-killed trees vastly overstated


There’s been no shortage of hand-wringing and threats of dire consequences about the millions of acres of beetle-killed pines in Montana’s forests. We’ve all been inundated with fear from fire experts who use computer models to predict massive, out-of-control conflagrations. But now, thanks to photos from space and some good old hard science, it looks like those fears have been vastly overblown.

The National Atomospheric and Space Agency (NASA) presented its findings recently in a press release that appropriately notes that evergreens, such as the lodgepole, white bark and Ponderosa pines being attacked by the beetles, “don’t change color with the seasons.” (You can read the report here: This is no particular news to Montanans, who have watched the march of the red and dead forests for years now be it spring, summer, fall or winter.

The tiny, but incredibly lethal, insects bore through the bark and then slowly but surely eat their way through the tender cambium layer beneath, destroying the xylem and phloem, interrupting the flow of nutrients, sap and water, and killing the trees in short order.

Despite all the uproar and predictions of catastrophe, the beetles have been around as long as the forests and are simply part of the forest ecosystem. They kill the trees, which then either burn and release their seeds, as in the case of lodgepole pines, or remain standing for a while and eventually fall down to provide nutrients to the forest floor and food and homes for many other species of birds, insects and animals. No big mystery here, just the great cycle of life with or without man’s intervention.

But recently, the beetles have multiplied exponentially and the areas of dead trees have followed suit. From northern Canada to Colorado’s southern border, tens of millions of acres of trees have fallen victim to the tiny bugs. Their current profligate reproduction has been traced back to the effects of global warming. Because we no longer have extended periods of below-zero weather during our winters, it no longer gets cold enough to kill the beetles. Thus, instead of living a limited life-cycle of boring and breeding only once, they are surviving the winters and breeding two or even three times in a single year.

The resulting mass of red trees naturally led people to believe that the danger of massive forest fires would be the result because, as we all know, dead trees burn better than green ones, right? Thus, it was not a stretch to believe that a lot of dead trees are going to burn more ferociously than a forest of green trees.

But in that assumption, it appears both the “healthy forest” proponents and fire behavior experts have been incorrect. Sometimes things look much different if you only take the time to step back away from them, and so it is with the NASA research.

As Yellowstone National Park Vegetation Management Specialist Roy Renkin put it: “I’ve heard [the tinderbox analogy] ever since I started my professional career in the forestry and fire management business 32 years ago,” he said. “But having the opportunity to observe such interaction over the years in regards to the Yellowstone natural fire program, I must admit that observations never quite met with the expectation.”

Indeed, the LANDSAT images from orbiting satellites revealed what appeared to be swaths of beetle-killed trees using near-infrared photography to determine the difference between live and dead trees. But to make sure they were, in fact, beetle-killed trees, the scientists went out on the ground around Yellowstone. Their investigations positively identified the accuracy of the space images and led the scientists to question the standard assumption of a correlation between areas of beetle-killed pines and large wildfires.

The next thing they did was overlay the beetle-killed trees with maps of recent large fires. But guess what? The fires and the beetle-killed trees didn’t match up. “Their preliminary analysis indicates that large fires do not appear to occur more often or with greater severity in forest tracts with beetle damage,” reads NASA’s report. “In fact, in some cases, beetle-killed forest swaths may actually be less likely to burn.”

In fact, what the researchers found out is that “while green needles on trees appear to be more lush and harder to burn, they contain high levels of very flammable volatile oils. When the needles die, those flammable oils begin to break down. As a result, depending on weather conditions, dead needles may or may not be more likely to catch and sustain a fire than live needles.”

Moreover, they concluded that “when beetles kill a lodgepole pine tree, the needles begin to fall off and decompose on the forest floor relatively quickly. In a sense, the beetles are thinning the forest, and the naked trees left behind are essentially akin to large fire logs. Just as you can’t start a fire in a fireplace with just large logs and no kindling, wildfires are less likely to ignite and carry in a forest of dead tree trunks and low needle litter.”

“It’s easy to think, ‘It’s more damaged so more likely to burn,’” said University of Wisconsin forest ecologist Phil Townsend, who worked on the project. “That’s why it’s important to ask questions and not take everything as gospel truth, but go out and see if what we think is happening in our mind is really happening on the ground.”

The science is now clear and convincing. It’ll be interesting to see if the politics will follow suit or stick with the Bush “Healthy Forest” propaganda to increase logging. Somebody ought to tell Sen. Tester right away that the premise of his Forest Jobs and Recreation Act is totally bogus. Then we ought to let the Forest Service in on the truth and put an end to frivolous timber sales. And finally, Montanans should take a deep breath and put the threats and fears of massive conflagration due to dead trees in the “Junk Mail” box where it belongs.

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