Environmental
The environmental impacts of genetically modified organisms have sparked spirited debate around the world. So far, the majority of the debate has focused around edible crops, the most prevalent GM industry to this point. ArborGen seeks to corner a unique place in the market, developing instead genetically modified forest trees. This application is in the budding stages in most countries: in the United States, ArborGen has a pending non-regulated license for its eucalyptus trees. ArborGen has already conducted several tests within the country, however, at sites in Alabama and Florida.The first six minutes of this video present an excellent overview of the environmental issues, which I’ll discuss below.
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Effects of Reduced Lignin:
Lignin is a component of plant cells that "provides strength and rigidity to plants and to plant structures such as xylem, which allows for the transport of water; and sclerenchyma and bundle sheath cells, which provide a natural barrier to microorganisms." (Pedersen) . In short, lignin provides an important service to trees by giving them stronger cells, therefore making them more resistant to insect and fungus invasion. Decreased lignin could increase the need for pesticides, and is likely one of the reasons GE trees with this modification also have modifications such as Bt and herbicide resistance. This decrease in overall strength also leaves trees more vulnerable to extreme weather such as wind, many of which are projected to increase with global warming (Canadian Forest Service). On the other hand, "lignin limits the use of wood for fiber, chemical, and energy production" (Wen-Jing Hu). A decrease in lignin content allows for cheaper pulping (a process crucial to IP's paper production). It also allows for faster tree growth as decreased lignin increases cellulose production. (Wen-Jing Hu). GE trees with this modification, therefore, will grow more quickly and be easier to use industrially, but will be weaker, requiring more toxic inputs such as pesticide, and leaving the trees more vulnerable to the effects of global warming.
Herbicide Resistance: All hail Monsanto
Built in resistance to herbicide spells one thing: increased use of herbicide. Herbicides are used widely in the agricultural systems of the world and allow for sustained monocropping, but their negatives effects to health and environment are thoroughly documented. Among these are the threat posed to bee populations, the loss of biodiversity and ecosystem health and the poisoning of animals and humans through high level exposures.
Bt- and its effects on natural forest processes
Bacillus thuringiensus, bt for short, is a pesticide that fends off invasion from fungus and insects. A GE application "will cause the pesticide to express itself in every cell of the tree" (Pseudotsuga Populus). While this strengthens a tree against fungus and insects, bt has been shown to leak profusely into the soil from tree roots (Pseudotsuga Populus). This is problematic in native forests, as fungi play an important role in natural decomposition, a crucial process in the natural cycle that allows for the return of nutrients into the soil. While bt is useful for protecting trees during their lifespan, it could have devastating effects in an ecosystem over time.
Forest Fire
Forest fires, although a natural occurrence, have the potential to release huge quantities of carbon dioxide into the atmosphere at one time, and also devastate large amounts of an ecosystem. While forest fires offer an ecosystem service (returning nutrients to the soil, ensuring the cycle of succession, clearing forest floors), their pattern and frequency are endemic to geographical location. This means that patterns for forest fire occurrence are established€”ecosystems have ways of dealing with these natural fire cycles, and have done so for millennia. Below is a map produced by the EPA of natural fire regimes (EPA).
However, humans have the potential to affect these patterns: in fact, they have a history of doing so extensively. These affects can be catastrophic: increasing biological damage to ecosystems through the increased intensity and frequency of forest fires beyond normal capacity in a specific area. Some examples of this include the €˜no burn' policy that allowed for an unnatural amount of debris on the forest floor. GE trees have the potential to impact this forest-fire equilibrium in several ways. First bt, as described above, inhibits decomposition, which could increase debris in a plantation, and if bt is spread through leaching into the surrounding forests, would increase this debris there as well. Also, the introduction of GE trees may include new variables that could increase forest fires. For example, ArborGen seeks to introduce its genetically modified Eucalyptus in the USA. The Eucalyptus is notorious for its flammability (Santos). This is both because of the debris it creates and its high natural oil content. While the eucalyptus has evolved with fire to be resistant to it, high concentrations of these tress may threaten surrounding forests that have different fire regimes and resistance.
Exotic Invasive?
ArborGen says that genes won't spread because its trees grow on plantations, not in forests, and are engineered to be infertile with impaired pollen production. The EPA also claims that their tree "has not been categorized as invasive." Envirnonmental Assessment (May 2009). However, even in GE crops designed to be infertile, it is approximated that 1% will still be capable of producing offspring. This is testified to by the number of law suits that surround the spread of other crops with genetic modifications into neighboring fields. The irony is that these suits are usually against the non-gmo farmer, for proprietary rights by the corporations who own the patents for the genetic modifications. Often, genetically modified organisms are picked for their hardiness and can therefore be even more of a potential threat as exotic invasives. ArborGen’s Eucalyptus, for example is a highly invasive plant were it not for the “sterility” of its genetic modifications.