Noutăţi | Eficienţa Energetică

http://news.smh.com.au/breaking-news-technology/group-seeks-forest-restoration-to-cleanse-planet-20110314-1bt6o.html

Redwoods and sequoias towering majestically over California's northern coast. Oaks up to 1,000 years old nestled in a secluded corner of Ireland. The legendary cedars of Lebanon.

They are among the most iconic trees on Earth, remnants of once-vast populations decimated by logging, development, pollution and disease. A nonprofit organization called Archangel Ancient Tree Archive is rushing to collect their genetic material and replant clones in an audacious plan to restore the world's ancient forests and put them to work cleansing the environment and absorbing carbon dioxide, the greenhouse gas largely responsible for global warming.
"In our infinite wisdom, we've destroyed 98 percent of the old growth forests that kept nature in balance for thousands of years," said David Milarch, the group's co-founder. "That's what we intend to put back."
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Milarch, a tree nursery operator from Michigan, and sons Jared and Jake have been producing genetic copies of ancient trees since the 1990s. They've now joined with Michigan businesswoman Leslie Lee and a team of researchers to establish Archangel Archive, which has a staff of 17 and an indoor tree research and production complex.
Its mission: Clone the oldest and largest individuals within the world's most ecologically valuable tree species, and persuade people to buy and plant millions of copies _ on factory grounds and college campuses; along riverbanks and city streets; in forests, farms, parks and back yards.
"The number of these ancient survivors that go in the ground will be the ultimate measure of our success," said Lee, who donated several million dollars to get the project off the ground and serves as board chairwoman. The group hopes donations and tree sales will raise enough money to keep it going.
Scientific opinion varies on whether trees that survive for centuries have superior genes, like champion race horses, or simply have been in the right places at the right times to avoid fires, diseases and other misfortunes. But Archangel Archive is a true believer in the super-tree idea. The group has tracked down and cloned some of the biggest and oldest of more than 60 species and is developing inventories.
The plan is eventually to produce copies of 200 varieties that are considered crucial. The trees preserve ecosystem diversity, soak up toxins from the ground and atmosphere, store carbon while emitting precious oxygen, and provide ingredients for medicines. Rebuilding forests with champion clones could "buy time for humanity" by mitigating centuries of environmental abuse, said Diana Beresford-Kroeger, an Ontario scientist who studies the roles of trees in protecting the environment.
California's coastal redwoods and giant sequoias, the world's largest trees, are best suited for sequestering carbon because of their size, rapid growth and durability, said Bill Libby, a retired University of California at Berkeley tree geneticist and consultant to Archangel Archive. The longer a tree lives, the longer its carbon remains bottled up instead of reaching the atmosphere.
"They grow like crazy," Libby said. "I have a clone of what used to be the world's tallest redwood tree in my back yard. It's still a baby, only 30 years old. It's already taller than anything around it, probably 80 to 100 feet (25 to 30 meters)."
Archangel Archive crew members have taken cuttings from redwoods and sequoias between 2,000 and 3,000 years old. Among them: the Stagg tree, ranked the world's sixth-largest sequoia by the U.S. Forest Service; and the Waterfall sequoia, considered the widest tree on Earth at ground level _ 155 feet (47 meters) around.
Three dozen coastal redwood clones and nine of the giant sequoias have taken root in the Copemish facility and another in Monterey, California, David Milarch said. The group also has successfully cloned sprouts from stumps of a dozen redwoods that were felled years ago, including one 35 feet (10 meters) in diameter.
The group uses several processes to develop clones. One is micropropagation, in which branch tips less than an inch long are planted for weeks in baby food jars containing gel-like mixtures of vitamins, fertilizers and hormones and placed on shelves under artificial lights. Eventually they are moved to pots of soil. Another method is to place tips up to 8 inches (20 centimeters) long in soil blends and grow them in mist chambers.
Terry Root, a Stanford University climate change expert, said giant tree clones could help fight global warming if large numbers are planted where conditions favor their long-term survival. "You can't put a redwood or giant sequoia just anywhere," she said. Location is also an issue in cities. Big, shady trees could lower home energy costs in the summer but could shed limbs and cause damage to houses if planted too close.
Finding genetically superior trees has been challenging, but group leaders acknowledge their biggest hurdle may be selling the public on the urgency of restoring the world's ancient forests.
David Milarch said he was aghast to learn that vast tree plantations were being cultivated in Ireland _ not with native oaks, but with pine and cypress imports from California that would grow quickly and be harvested instead of helping cleanse and cool the planet as native champions would do.
"It makes no sense to plant monocultures of exotic species while the last of your giant native trees are in danger of blinking off the earth," he said.