Trees

Trees, which have long life cycles and grow in intricate ecosystems, are in the earliest stages of domestication. Planting genetically engineered (GE) trees poses potentially devastating environmental risks. Greenpeace is calling for an immediate ban on the release of GE trees into the environment, because of the threat of irreversible genetic pollution.

Scientists say that physical confinement of pollen, and in some cases even the seeds, from forest trees is for all purposes impossible. Aware of the problems of gene escape, the Biotech industry often claims that engineering tree sterility is a solution. But engineering persistent sterility could prove very difficult, and in fact such research constitutes only a tiny fraction of GE tree research. Furthermore, GE-sterile trees could revert to fertility in the future as a reaction to external stressors and pass genes for sterility onto wild populations.

The introduction of foreign genes into any organism can cause unintended side effects for ecosystems. For example, scientists are studying how to reduce lignin content in trees. Lignin is a material that adds strength and rigidity to plants, but makes it harder to pulp wood for paper. But reduced lignin could speed up the decomposition of trees, altering soil ecology, structure and fertility.

Genetically engineering can also produce unwanted and unexpected side effects, many of which will be hard to detect in GE trees, due to their long life spans. It may take several years for undesired traits, or instabilities in the desired traits, to express themselves.

One sought-after outcome of GE tree research is species that grow faster. Such trees might quickly deplete soils through unusually rapid uptake of nutrients. In addition, fast-growing super trees might put increased pressure on water supplies, a scarce resource in many regions. Moreover, if the fast-growth trait were transferred to wild relatives, these plants could quickly become pests, with serious ecological consequences.

Researchers are also engineering trees to become resistant to herbicides (weed-killers). Such GE trees could result in increased aerial spraying of weed-killers, which would considerably increase the risks of chemicals entering water-ways and damaging ecosystems. Furthermore, herbicide- or insect-resistant trees could transfer their extra "resistance genes" to wild relatives. These plants could become "super weeds".

Thus far, no applications for unrestricted, commercial use of GE trees have been filed. However, experimental releases with GE trees have been approved in several countries including the USA, UK and South Africa with more than 200 field trials in the US alone.

For more information download the Greenpeace report - Pulp Fiction, Genetically Engineered trees.