Effects of pine beetle outbreak might not be as bad as predicted, experts say

By CHRISTINE PETERSON Star-Tribune staff writer

Predictions were dramatic. Streams would rise. Nutrients would be lost. Fire would ravage the red forests in ways we could only imagine.

The mountain pine beetle epidemic was severe, the worst in North America’s recorded history. It crept through mountainsides in the West and left behind a scar of red and gray trees.

As the epidemic nears its end in some areas like the Medicine Bow National Forest, some scientists are discovering their predictions may have been backward. Stream flow has not increased, and nutrients are still in the ground.

“The big trees died, but there are still residual trees left,” said Brent Ewers, a botanist at theUniversity of Wyoming and one of the scientists on the study. “These forests are more resilient to the outbreak than we thought.”

Ewers and fellow researcher Paul Brooks, a hydrology professor at the University of Arizona, presented their information recently at the fall meeting of the American Geophysical Union in San Francisco.

The researchers started studying the Medicine Bow and Roosevelt national forests in 2008 with experts from across the western U.S. They wanted to know how much stream flow would increase and how much carbon and nitrogen would flood down the mountains.

Snow falling in healthy forests collects on needles and evaporates. What falls on the ground is often used by trees before it reaches groundwater or streams, Brooks said. The rest flows into our rivers, lakes and reservoirs amounting to the bulk of the West’s water supply.

Most people believed that without trees drinking water and tree needles cradling snow to be evaporated, more water would flow down into streams, he said.

They also thought carbon and nitrogen, chemicals released from trees after they die, would pollute the water. Both chemicals in large quantities can become toxic and could have required pricey solutions at water treatment plants, Brooks said.

An increase in water and chemicals can be effects after small fires or isolated logging projects. What some scientists didn’t realize was the sheer extent of the pine beetle damage. Instead of localized fires or logging, pine beetles swept through entire mountain ranges, burrowing in large trees, laying larvae and spreading their deadly fungus.

Snow then fell in large open areas, evaporating and blowing away the same as if it had fallen on fresh pine needles. New plants and trees on the ground flourished without the big, older trees, drinking the excess water, Brooks said.

Remaining trees and plants are absorbing nitrogen, causing the forest to actually grow faster than before, Ewers said...more

I don't understand.  We were told global warming had caused the huge beetle infestation.  Global warming is bad. But then there's mother nature, who is more resilient than all the researchers and envirocrats combined.

After the kill, Part 1: Beetle epidemic changed the face of High Country forests

If mountain residents hope to keep building their homes and towns along the wildland-urban interface, they must understand that sudden, drastic change is inevitable and prepare their own properties as best they can. And if Coloradans wish to continue reaping the benefits of forests, including recreation opportunities and a source of precious water in the arid West, they must take an active role in responding to disturbances and protecting the landscape. The pine beetle’s sweep in Colorado’s western mountains combined with the devastating Front Range wildfires of the last decade have captured the attention of individuals as well as federal, state and local governmental agencies. These disturbances have no regard for boundaries between public and private lands. In the new reality, all interests must work together through partnerships to respond to disaster and protect the landscape supporting lives and livelihoods. With the passage of the beetle tsunami, both eyes and views are opening to see another perspective of the epidemic. Numerous studies following the destructive 2002 Hayman fire and beetle onset have shown that the link between wildfires and beetle kill is dubious at best. In fact, beetle kill may be nature’s way of preventing massive fires. It helps thin lodgepole, which like to grow in dense stands. It reduces the amount of fuels in forest canopies when the pines die and drop their needles. “Pine beetles outbreaks are not an exotic thing that occurs, they’re part of the natural system,” said Craig Magwire, a district ranger with the U.S. Forest Service. He’s worked to mitigate the pine beetle fallout since the first signs of an epidemic in Grand County. But while pest outbreaks are normal, what makes the current epidemic unusual is its scope, wiping out virtually every mature lodgepole in western Colorado’s forested landscape. And while the link between wildfire danger and massive stands of insect-ravaged trees is still the subject of debate among scientists, the epidemics share a common cause. Colorado’s recent record-breaking wildfires and unprecedented beetle kill were both fueled by drought. Drought weakens trees’ natural pest defenses. And drought leads to dry conditions and dangerous fire risks. Colorado’s long dry spell through the 1990s and 2000s created a perfect storm for both insect outbreaks and wildfire conditions...more