2015-04-19

Forests killed by the mountain pine beetle don't pose increased wildfire risk

In the past decade, the mountain pine beetle has severely impacted pine forests across more than 50 million acres of western North America. In the aftermath of this epidemic is there a significant increase in wildfire threat? For many tasked with managing wildfires the answer is a resounding "yes." However, a recent research paper from a team of scientists based in Colorado suggests that forests killed by the mountain pine beetle do not pose an increased risk to wildfire. The paper relies on the recent area burned in wildfire superimposed on the area recently infested by the beetle. Because the areas of recent wildfires and beetle activity don't overlap, the authors contend that the risk posed by the mountain pine beetle is overblown. Those in the wildland fire management and suppression fields who disagree base their disagreement on actual observations of extreme fire behavior in forests killed by the mountain pine beetle.

So who is correct in this debate? A paper published in 2014 in the online journal Fire Management Today sought to address this problem by looking at two critical factors: the history of beetle attacks in a forest and the time since beetle infestation. To many people, it would seem that the year after initial infestation when the tree crowns all turn red is the time of highest risk. It certainly can be, provided other elements of hazard are also present. Red-attacked trees, in addition to heavy accumulations of dead wood on the forest floor, are a recipe for extreme fire behavior. Red-attack trees and very little or no dead wood on the forest floor is much less of a risk and, once the needles fall off dead trees, fire risk can be low for quite some time.

The authors of the paper challenging wildfire risk do not describe the fuel structure in these forests - only the state of the tree crowns (red or grey). The lack of attention to surface fuels is a weak point in such studies. Throughout much of British Columbia, Canada, over the last several decades mountain pine beetle outbreaks have been fairly common. With each passing epidemic more and more trees in the forest are killed by beetles. After large outbreaks with high mortality, dead trees gradually fall and accumulate on the forest floor. Heavy accumulations of downed wood associated with past beetle outbreaks have contributed to some very impressive fire behavior. Since 2009, British Columbia has seen large areas of beetle-killed forest burn under very high intensity and severity with much of the area burned having experienced significant epidemics in the 1980s and mid-2000s. The fuel structure in these forests has included red and grey crowns plus large quantities of dead wood on the forest floor. Unfortunately, to mitigate the threat there are only a few options and none are very palatable to the public. An increase in logging of the attacked or soon to be attacked trees has been advocated for large areas in the West but it can often lead to a worse fuel hazard if not done diligently; large-scale prescribed burning has been done in some areas with the intent of breaking up a contiguous landscape of fuel; and, relying on natural ignitions to reduce the hazard can be effective provided the fire doesn't burn too severely.

2015-03-26

Study Exonerates Beetle From Claims Of Added Wildfire Risk

It is climate change, not the mountain pine beetle, we should be worried about.

Researchers have found that forests infested by the mountain pine beetle (Dendroctonus ponderosae), which is present in thousands of miles of forest in western North America from Mexico to British Columbia, has no added effect on the risk of wildfires compared to forests unaffected by the insect. Instead, it is more important for policy makers to address the bigger causes of forest fires, the researchers say.

"The bottom line is that forests infested by the mountain pine beetle are not more likely to burn at a regional scale," says Sarah Hart, postdoctoral researcher at the Colorado University-Boulder and lead researcher. "We found that alterations in the forest infested by the mountain pine beetle are not as important in fires as overriding drivers like climate and topography."

Battling the Beetle: Pines in the Northwest are Under Threat

According to an article appearing in the April 2015 issue of National Geographic, more than 60 million acres of forest — from northern New Mexico through British Columbia — have suffered die-offs since the 1990s due to the spread of the mountain pine beetle (Dendroctonus ponderosae).

The beetles bore through the bark and create tunnels beneath it, where the females lay eggs. When the eggs hatch, the larvae feed on the bark as well.

But it gets worse. The beetles are fungus farmers that carry spores on their bodies. When they tunnel under the bark, the spores grow, providing an excellent food source for pine beetle larvae — but it simultaneously damages the trees, including lodgepoles, ponderosas, white pines, jack pines, and others.

2015-03-25

Beetles aren't to blame for forest fires, study confirms

Over the last two decades, the mountain pine beetle (Dendroctonus ponderosae) has infested millions of acres of forest in the Rocky Mountains.

But while the small, black-colored species of bark beetle may be destroying ponderosa and lodgepole pine trees, it's not making forest fires more probable or powerful -- that according to researchers at the University of Colorado Boulder.

The beetle and microbial partners can be found infesting pine trees throughout western North America, stretching from Mexico to central British Columbia. And the insect's destruction has grown more prevalent in recent years, as warmer temperatures and lengthier droughts both encourage the pest's population growth and weaken trees' defense mechanisms.

2015-03-21

Forestry a bright spot for Alberta

Today is the International Day of Forests – a United Nations-sanctioned celebration of the role that forests play in our lives. Forests are integral to the environment, economy, and culture of Alberta. Roughly 38 million hectares are covered by forest in Alberta – that’s an area slightly larger than Japan.

One of the things that we can be very proud of in Alberta, and across Canada, is our rigorous approach to forest management. The regeneration of areas that have been harvested is the law and has been for several decades in our province. Several trees are replanted for each tree that has been harvested. Alberta’s forest industry planted 65 million trees in 2014 – roughly 16 trees for every Albertan. Thanks to forward thinking policy and aggressive forest regeneration programs, Canada retains a higher percentage of its original forest cover than any other nation in the world.

Managing our forests is a unique partnership between government and industry. In Alberta, virtually all of our forests are on Crown land. In return for the right to harvest timber, forest companies are required to take into account a broad suite of outcomes including water quality, animal habitat, and biodiversity. Companies and government invest considerable amounts into forestry research and management techniques to ensure that these outcomes are being reached.