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Special trees that grow faster, fight pollution, produce better wood, and even sense chemical attacks are being planted by scientists in the US.
When 40 percent of Hawaii's US$14 million-a-year papaya (木瓜)industry was destroyed by a virus five years ago, work began on creating genetically engineered (转基因的) trees.
Researchers successfully introduced seeds that were designed to resist the virus. Since then, more and more people have been testing genetically engineered trees.
Some researchers put special bacteria into trees to help them grow faster and produce better wood. Others are trying to create trees that can clean polluted soil.
Meanwhile fruit farmers are looking for trees that are strong enough to resist worms, and paper companies want trees that produce more wood and therefore more paper.
