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Tuesday, December 9, 2008

Tree's rapid decline sounds alarm on global warming

WASHINGTON — The whitebark pine, a tree found in the high elevations of the western U.S. and Canada, is being killed as a consequence of global warming and should be protected as an endangered species, an environmental group formally told the Interior Department Tuesday.

If the federal government accepts the scientific arguments in a petition by the Natural Resources Defense Council, it would be the first time a wide-ranging tree has been added to the list. The NRDC also sees an endangered designation as a warning about worsening climate change.


The listing would require the government to look at a variety of options that scientists have suggested might help preserve the tree, choose what might work and spend enough money to put those ideas into practice.


Mature whitebark pines are often gnarled and twisted because they grow slowly in the tough terrain of the high mountains of California, Washington, Oregon, Idaho, Montana, Wyoming and Nevada, and in British Columbia and Alberta. It's typically found at the treeline or at somewhat lower elevations mixed with other conifers.


The whitebark pine has declined dramatically due to a triple threat — a disease called the white pine blister rust; the mountain pine beetle, which thrives in the warmer high-altitude conditions produced by the burning of fossil fuels, and forest management practices that have allowed other trees to crowd it out, the NRDC's petition said.


Warming also will limit the range of the whitebark pine, the petition said. Many live more than 500 years.


"It's kind of a wakeup call about the scope of the problems we're going to be facing," said NRDC scientist Sylvia Fallon, an ecologist who was one of the authors of the petition. "All of the pieces of the ecosystem it holds together will also be affected by its loss."


The whitebark pine stabilizes the soil and shades the snow, providing water over longer periods for other plants. Grizzly bears, smaller mammals and birds eat its seeds, and elk, grouse and other mountain animals find shelter beneath it.


The tree has been declining in numbers for 50 years. In recent years, climate change has started to make the threats worse, due to shorter periods of cold that kill the beetle and extended periods in which the trees are exposed to spores from the blister rust, Fallon said.


Different forms of fire management might help the tree. The whitebark pine thrives in areas opened up by fires, but firefighting in the West has created more mature forests over larger areas. And while natural fires can be good for the tree, fire also can be an unnatural threat with changes in climate leaving drier forests, Fallon said.


The petition argued that the current extent of the losses of whitebark pines and the future threat of continued global warming put the tree at risk. Under the law, a species is considered endangered if it is in danger of extinction in all or a significant portion of its range.


Fallon said that early studies show that a small percentage of the trees might have some defense to the beetle. If scientists can find a way to control the beetle, planting resistant trees might make sense, she said.


The Interior Department secretary and the department's Fish and Wildlife Service have 90 days after receiving the petition to determine whether the tree is threatened or endangered. The period spans the presidential transition. The whole process would take two years.


Fallon said the timing of the petition had nothing to do with change at the White House. NRDC's Montana office had been studying the threats for a long time, she said.


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