Ecologists question research on burns in bug-killed forests after Montana fires

Photo by Matt Stensland

Thanks to Derek for submitting. From the Missoulian here.

Last summer, a wall of flame roared through a three-mile stretch of tinder-dry, bug-killed lodgepole pine forest and forced a large group of firefighters to retreat to a safety zone.

An official said later the flames moved through the trees like fire does through grass.

In the upper West Fork of the Bitterroot, another fire blew through 17,000 acres in a day. Much of that area also was covered by lodgepole pine killed by mountain pine beetle.

That unusual fire behavior now has some fire ecologists questioning conventional research that suggests that wildfires won’t burn as fiercely through forests filled with bug-killed trees.

“We definitely saw some unusual and pretty amazing runs under fire conditions that we would normally consider to be moderate,” said Matt Jolly, a research ecologist with the Rocky Mountain Research Station’s Fire Sciences Laboratory in Missoula.

Earlier research based on modeling suggested that stands of dead and dying trees were not as prone to flare into fast-moving crown fires. And if the fire did manage to make it into the crowns, the research said it was unlikely to stay there long.

Firefighters and researchers saw something quite different happen this summer.

“These fires were quite a bit more active than what the conventional research suggests,” Jolly said. “The problem is most of the conventional research used simulation models. If you don’t have good observations, then you have to assume the models are correct.”

Before this year, the past three summers were marked by very wet Augusts, which is typically the peak of the wildfire season in western Montana.

“We’ve been dodging the bullet, if you will, over the last three seasons,” Jolly said.

Canadians have been reporting similar fires in their own forests filled with beetle-killed trees for a number of years.

The fires this summer burned in conditions that weren’t considered extreme over an understory that was often still green. At times, the solid walls of flame reached from the ground to far above the canopy.

In some cases, the fire was burning through a forest of mostly dead trees that had already shed most of their needles.

***

Jolly said trees attacked by mountain pine beetles start a downward spiral that makes them more susceptible to fire early on. Once the trees die, their needles turn red before falling off. The red needles are extremely flammable.

Once the needles fall off, the forest has a gray appearance. This summer, Jolly said the fires blew through those standing gray stands.

“A lot of people have proposed that once the needles fall off, there’s little opportunity for a crown fire,” he said. “In these gray stands, you essentially have a vertical dead fuel with extremely low fuel moistures that once ignited, can create a flaming front.”

Fire researchers also noted the fires were quick to form a column that created its own weather, which further enhanced burning conditions.

For these fires to occur, Jolly said fuel conditions, weather and topography have to be aligned just right.

In many cases, the fire conditions were not considered extreme.

“These fires burned under less than extreme conditions in the same way that a healthy stand would burn under extreme conditions,” Jolly said.

The dead stands are made up of vertical fuels that respond quickly to changes in the weather and humidity levels.

“That’s why it happens very quickly,” he said.

***

With hundreds of thousands of acres of bug-killed stands scattered across the West, Jolly said there is a “very real possibility” of seeing more fires like this past summer’s.

“It’s totally dependent on weather,” he said. “As soon as we have a dry year like we saw in 2000 or 2003, which came with a very prolonged period of drying, it will be very interesting to see what happens.”

Bitterroot West Fork District Ranger Dave Campbell said research like Jolly’s will be important to those who fight and attempt to manage the blazes.

“This was a good opportunity for us to partner with the fire lab, which has some of the best fire scientists around,” he said. “Hopefully, we will be able to make the models for the future.”

Read more: http://missoulian.com/news/local/article_33e5c862-f930-11e0-9771-001cc4c03286.html#ixzz1bEYungr1

Experts disagree about griz numbers, implications

Figure from the Wyoming 2002 Grizzly Management Plan

Interesting story from the Cody Enterprise..

By MARK HEINZ | Posted: Monday, October 17, 2011 3:57 pm

Grizzly numbers in the heart of the Yellowstone area habitat appeared to have dipped, but some experts’ opinions vary regarding how much, and why.

There are an estimated 593 grizzlies in the Greater Yellowstone Ecosystem, compared to 602 last year, according to a new study.

The number of bears killed, for various reasons, over the past few years “has taken a powerful bite out of the population,” said ecologist Chuck Neal of Cody, who is retired from decades of field work with the BLM, Forest Service, and contract work with the U.S. Fish and Wildlife Service.

“The take-home message is the population seems to have reached a plateau. We might be exceeding the female morality level,” said Mark Pearson, conservation program director with the Greater Yellowstone Coalition.

But Game and Fish bear expert Mark Bruscino said he thinks the population remains robust.

“The survey behind the study was only on the grizzly population in the core of the habitat, and only for one year,” he said.

“In areas where we haven’t done systematic sampling, the bear population continues to grow, both in terms of numbers and distribution. Overall, the grizzly population is doing quite well,” Bruscino said.

He was among experts and other interested parties who attended a recent meeting in Bozeman, Mont., of the Yellowstone Ecosystem subcommittee of the Interagency Grizzly Bear Committee. The IGBC includes representatives from G&F, Forest Service, Park Service, BLM, USFWS, the U.S. Geological Survey, wildlife agencies in Idaho, Montana and Washington, and Canadian Wildlife Service.

Much of the discussion centered around a population study, done mostly by USGS and USFWS researchers,

Even a slight dip in grizzly populations can be worrisome to bear experts and conservationists, because the bruins’ reproductive rates are much lower than other wildlife species.

There seems to be consensus over the idea that grizzlies are ranging farther and consequently getting into more scrapes with people. But there is some disagreement over why.

There is also differences of opinion over whether grizzlies should be delisted, and perhaps even hunted, in Wyoming.

Bruscino thinks that’s a good idea; Pearson and Neal said they want to bears retain federal endangered species protection.

A ruling from the 9th U.S. Circuit Court of Appeals on the matter is expected soon.

Looking for food?

Bears are losing some key ingredients of their diet because of the decline in white bark pine and cutthroat trout in the heart of grizzly country, Neal and Pearson said.

“Habitat quality has been in decline, primarily because of the loss of white bark pine to beetles,” Neal said.

Grizzlies like to feast on pine cone nuts, which are rich in fat and calories.

“It’s an important food source for them right now, as they fatten up for winter,” Neal said.

“We must take into consideration the effects of climate change on their food sources,” Pearson said. “With less food available in the interior habitat, bears are roaming into the fringe areas.”

Neal recalled the last time grizzlies began to disperse widely, get into trouble and, consequently, get killed in higher numbers.

That was back in the 1970s when the Park Service decided to shut down open landfills in Yellowstone, where bears had gotten accustomed to easy gorging.

Now, essentially the same thing is happening. But instead of the loss of a bad, artificial food source, grizzlies are losing natural sources, Neal said.

But Bruscino is dubious about the idea that bears are wandering to find food.

Rather, more bears are showing up in more places because they’re being pushed out by grizzlies that have laid claim to the interior habitat, he said.

Bruscino said according to what he knows, grizzlies are far more likely to adapt to new food sources in their territory, rather than wander somewhere else.

“Bears are the quintessential omnivores,” he said.

“The core habitat is saturated We just don’t see bears leaving their home ranges, he said. “Fat levels on bears in the core of the Yellowstone habitat indicate those bears are doing very well nutritionally.”

Neal said he doesn’t agree with the idea that habitat saturation is behind conflicts with people.

“They are getting into areas where people themselves are expanding their presence,” Neal said. “It’s not so much ‘saturated’ habitat,’ as it things like trying to raise chickens and sheep on the edge of occupied grizzly habitat.”

A question of tolerance

Bruscino said the GYE grizzly population has met or exceeded all the biological goals set when the recovery program started.

“We need to do more on the fringes to reduce conflicts,” he said. “In my opinion we could be hunting grizzlies, today, and it would not be detrimental to the population.”

Neal and Pearson said the answer isn’t to delist bears now, but rather to allow them to expand their habitat.

“The key has never been numbers. It’s always been enough occupied, contiguous habitat,” Neal said.

Opinions might hinge on whether people see the GYC as essentially a “island” of wild habitat, with nowhere else for grizzlies to go, or as part of a larger network of places where the bears feasibly could roam, Pearson said.

For example, GYC favors enough interconnected habitat to allow for genetic exchange between the Yellowstone and Glacier Park grizzly populations.

But he noted that conflicts with people could ultimately drive policy.

“Human tolerance is absolutely going to be the deciding factor regarding where grizzlies can thrive,” Pearson said.

California resident Dave Smith, who worked for years in Yellowstone, and still frequently visits, agreed.

“Grizzlies have been on the Endangered Species List for 30 years now, and I think people are getting worn out,” said Smith, who has written two books about staying safe around grizzlies and other large animals.

“The Game and Fish in Wyoming is having to play ‘musical bears,’” by constantly trapping and relocating troublesome grizzlies, Smith said.

This raises some questions for those that know this part of the country… given our economic situation, are folks still building houses into or next to grizzly habitat? Is critical habitat designated for private land?

I was also interested in these quotes:

Bruscino said the GYE grizzly population has met or exceeded all the biological goals set when the recovery program started.

“The key has never been numbers. It’s always been enough occupied, contiguous habitat,” Neal said.

I am not very expert on ESA, but if there are population goals, can they shift through time? That could get discouraging to people trying to implement policy
if folks are moving the goalposts.

And if the problem with endangered species is not numbers, how do we decide what is “enough occupied continguous habitat”?