Climate change harms aspens

From the hillsides of extinct volcanoes in Arizona to the jagged peaks of Idaho, aspen trees are falling by the tens of thousands, the latest example of how climate change is dramatically altering the American West.

Starting seven years ago, foresters noticed massive aspen die-offs caused by parasitical insects. With warming temperatures and the after-effects of a brutal drought still lingering, the parasites are flourishing at the expense of the tree, beloved for its skinny branches and heart-shaped leaves that turn a brilliant yellow in autumn.

What foresters have termed Sudden Aspen Decline has more than just aesthetic consequences. Aspen trees provide a rich habitat for birds, elk, deer and other animals. The grasses that sprout under them—as much as 2,000 pounds per acre—hold water that is needed by metropolitan areas. The trees do not burn easily and create natural fire breaks in forests already ravaged by the pine bark beetle—another parasite that is thriving due to global warming.

“It’s just rolling through the forests,” said Wayne Shepperd, an aspen specialist at Colorado State University, said of SAD. Noting the number of other changes to western vegetation due to warmer, drier temperatures, he added: “Everything’s happening all at once. We’re living in interesting times here.”

—Los Angeles Timest

Looking for the Dark Ages

No place seems safe from the prying eyes of inquisitive astronomers. They’ve traced the evolution of the universe back to the “Big Bang,” the theoretical birth of the cosmos 13.7 billion years ago, but there’s still a long stretch of time— about 800 million years—that’s been hidden from view.

Astronomers call it the Dark Ages, and now they’re building huge new radio telescopes with thousands of detectors that they hope will let them peer back into the time the universe was 380,000 to roughly a billion years old, when the first stars and galaxies began turning on their lights.

If they succeed, it will be an unprecedented, three-dimensional look at a previously unknown swath of the cosmic history. Some astronomers compare the venture to Galileo’s first crude telescope.

For this voyage into deep time, astronomers are using radio telescopes because radio waves—which are much longer and slower than light waves are —can pass through cosmic dust clouds that optical telescopes can’t penetrate.

Because far-off radio signals are so faint, and so easily confused with background interference, only the largest telescopes can even hope to do the job. At least three major projects are under construction in the U. S., Europe and Australia.

Even more ambitious ones are proposed, possibly including a telescope on the dark side of the moon.