From "Gee, Ya Think" Dept. - Bark Beetle Devastation, Climate LInked

[hatrack]

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Through a combination of field sampling in buggy forests, computer analysis of tree growth rings and historical fire data, and careful examination of competing theories, forest scientists have reached a consensus that the woods of the Kenai Peninsula would not have been so thoroughly wiped out without an increase in the local summer average temperatures of some 2.5 degrees Fahrenheit since 1987. "The difficulty was you had a natural coexistent system between trees and bugs, and outbreaks had happened many times in the past," said Glenn Juday, a professor of forest ecology at the University of Alaska Fairbanks. "So what made this different?" Finding the answer involved a classic piece of scientific sleuthing. But the quiet background research was obscured for a while by noisier foreground political battles fought over mankind's supposed role in bringing on the epidemic, either through mismanagement of the forests or pollution of the earth's atmosphere with greenhouse gases.

For residents of the Kenai Peninsula, the loss of their forests came with little warning. When the spruce bark beetles first hit in the late 1980s, entomologists predicted the outbreaks would be relatively short-lived, killing off the oldest trees. Homeowners were instructed in defensive techniques such as stripping bark off red-needled spruce and felling trap trees. These efforts proved useless in the face of the coming beetle hordes, which attacked healthy young trees and flew so thick they left a brown tide line on the shores of Cook Inlet.

Today, beetle activity has abated because there are few mature trees left to attack. The last red-needle outbreaks on the Kenai could be seen this summer in the high country south of Turnagain Pass. The area is traditionally one of the last to lose snow in spring, but earlier melting in recent years may have made them vulnerable, entomologists say. With most of the Kenai's old forests now dead and rotting, the real beetle action lately has been to the west, in the Iliamna Lake and Kuskokwim River areas. New outbreaks have also been seen closer to Anchorage, in the Indian and Bird Creek valleys.

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Berg has gone on to do other work on the Kenai refuge, investigating treeline changes, for example, including the straightening up of the stunted alpine hemlock known as krummholz. Lately he has been taking core samples of drying muskegs, finding that the surface spread of woody plants such as blueberry and dwarf birch is a brand new phenomenon. Peat deposits dating back 10,000 years show no evidence of woody roots, he said. "The shrub invasion seems to be going full bore," Berg said. Ed Holsten, a retired forest service entomologist gradually won over to the global warming theory, said he expects Alaska will face more insect problems in the near future, even as the bark beetle's day fades. He mentioned such spreading pests as the birch leaf miner, which mottles birch leaves, and the larch sawfly. Not that the spruce bark beetle is going away. Scientists expect the bug will remain part of the warmer ecosystem, ready to nip off the young surviving spruce once they reach maturity. A handful of older trees seem resistant to attack, for unknown reasons. But Juday's chapter concludes that efforts to replant spruce and bring back the old forest on a new cycle may be doomed.

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http://www.adn.com/news/alaska/story/6956444p-6856250c.html

[kestrel91316]

1. Golly gee, who'd'a thunk it??????