Forests fall to beetle outbreak

By Ed Stoddard

MEDICINE BOW NATIONAL FOREST, Wyoming (Reuters) - From the vantage point of an 80-foot (25 meter) tower rising above the trees, the Wyoming vista seems idyllic: snow-capped peaks in the distance give way to shimmering green spruce.

But this is a forest under siege. Among the green foliage of the healthy spruce are the orange-red needles of the sick and the dead, victims of a beetle infestation closely related to one that has already laid waste to millions of acres (hectares) of pine forest in North America.

"The gravity of the situation is very real," said Rolf Skar, a forest campaigner with Greenpeace.

The plague has cost billions of dollars in lost timber and land values and may thwart efforts to combat climate change, as forests are major storing houses of carbon, the main greenhouse gas blamed for global warming.

The beetle outbreak, which has taken a lesser, but mounting, toll on spruce trees, could make it that much tougher to meet the ambitious target to reduce U.S. carbon emissions by 17 percent of 2005 levels by 2020 and 83 percent by 2050.

That is laid out in a climate bill that narrowly passed in the U.S. House of Representatives and waits Senate debate.

Many researchers have also linked the infestation in the U.S. and Canadian West to climate change, notably a dearth of winters cold enough to kill the voracious little bugs.

"Pine beetle infestations are cyclical in nature and have been occurring for thousands of years but what is making things worse now is the effects of global warming," said Skar.

"If you don't have the real cold extremes to kill off the larvae under the bark you are going to have extreme infestation events," he said.

CARBON FOOTPRINT

In the Medicine Bow National Forest, scientists are getting a first-hand look at the carbon implications.

The forest is home to the U.S. Forest Service's Glacier Lakes Ecosystem Experiments site in a tower with gadgets that, among other things, examine the "carbon flux" of the forest.

The site was established a decade ago, before the spruce beetle infestation, and gives scientists a unique chance to measure the changes to carbon storage wrought by the insects.

"We are getting readings here every half hour," said Colorado-based U.S. Forest Service scientist Mike Ryan, shouting above the wind as he pointed to an instrument that measures carbon. This gas analyzer resembles a small space capsule on the end of horizontal a metal pole.

In the terminology of trees and carbon, a healthy forest is a net "sink," with trees storing carbon as they grow. When they die and rot they "emit" carbon back into the atmosphere, and so a dead or dying forest becomes a "net source" of greenhouse gas, meaning it emits more carbon dioxide than it stores.