National Geographic : 1992 Jul
EarthAlmanac An Island A-slither: Alien Snake Overruns Guam They are ill-tempered, mildly poisonous, and up to ten feet long. On Guam they have multiplied into millions, decimated wildlife, crawled into homes, and even attacked infants. This menace , the nocturnal brown tree snake, has virtually no natural enemies, and the islanders' efforts at control have been to no avail. "We don't have any magic bul- lets," says Robert Beck of Guam's Division of Aquatic Wildlife and Resources. "Folks are having to learn how to live with the snakes." Native to the southwest Pacific, the snakes probably arrived on Guam, far to the north, as ship- board stowaways after World War II. In at least one area their density has reached an astonishing 30,000 a square mile; the 130,000 Guamani- ans are hopelessly outnumbered on the 209-square-mile island. The lean, mean eating machines have wiped out 9 of 12 native bird species and subspecies on the island. The endemic Guam rail and Micro- nesian kingfisher have been saved by captive breeding. In recent years the island has suf- fered hundreds of blackouts when climbing snakes short-circuited pow- er lines (and themselves). Traps, electric fences, and fumigants have so far had little impact. Another invasion is feared in Hawaii, where brown tree snakes have been found in aircraft arriving from Guam. National Geographic, July 1992 JOEL SARTORE ; WILLIAM BURT (BELOW) Old Tires Burn for Power, Add Rubber to the Road I: ·ke coat hangers breeding in the environmental closet, two billion used tires have piled up in the U. S.; 280 million more are discarded yearly. Two cleanup strat- egies are on a roll: burning tires to make electricity and adding scrap rubber to asphalt for roads. "Tires are like funny-shaped bar- rels of oil," says Robert Graulich of the Oxford Energy Company. An automobile tire does indeed contain about 2.5 gallons of oil, and Oxford runs two power-from-tires plants, including one in Connecticut (above). It burns 11 million tires a year, producing enough electricity to serve 15,000 people. A smaller plant operates in California, and two more are planned. The compa- ny's high-temperature combustion processes keep emissions within federal and state limits. By 1995 Oxford hopes to recycle more than 60 million tires a year. Tires can also be ground up and blended into asphalt. States that don't recycle scrap rubber in other ways will soon be required to use it in asphalt for federally funded roads.