• The UN has approved use of genetically engineered trees that take in more carbon than normal trees, and so help to offset industrial emissions.
• Hawaiian officials have approved pest-resistant papaya trees in response to infestations that nearly wiped out native populations. The new class of trees has already provided a critical economic boost.
• The Department of Defense has ordered research into arboreal warning systems - for instance, trees with foliage designed to change color in reaction to a biochemical attack.
Trees, the ultimate survivalists, will express only those genes that are necessary for their longevity. "When they escape, the [new genetic material] may act differently or it may not express at all," says Jim Hemrick, a tree-genetics expert at the University of Georgia in Athens.