GE Forest Trees –
The Ultimate Threat
Dr. Mae-Wan Ho and Prof. Joe Cummins
The ultimate threat
Genetically modified (GM) forest trees do not attract the same
immediate health concerns as GM food crops. But in reality, they
pose an even greater threat than GM crops because they impact
directly on natural forests that are essential for the survival of
World status of GM forest trees
Most genetic modification of forest trees have been done by
Agrobacterium-mediated DNA transfer; but bombardment with
DNA-coated particles, or ‘biolistic transformation’, has also
been used. Of the 205 permit applications listed at the end of
2003, 73.5% originated in the USA, 23% in other OECD member
nations (in particular, Belgium, Canada, France, Finland, New
Zealand, Norway, Portugal, Spain and Sweden) and 3.5% elsewhere (Brazil,
China, Chile, South Africa and Uruguay) . Four
traits account for 80% of the permit applications: herbicide
tolerance (32%), marker genes (27%), insect resistance (12%), and
lignin modification (9%). Of the tree species involved, Populus,
Liquidambar (Sweet Gum Tree) and Eucalyptus account for 85% of
Although commercial interest was low during the first ten years of
GM trees development, it has steadily increased since the late
1990s. By the end of 2003, 45% of the permits submitted were from
industry, mostly for transgenic poplars. But to-date there has not
been a concerted push for commercialisation of GM trees except in
China, where more than one million GM trees have been planted in
“reforestation” initiatives since commercialisation was
approved by The Chinese State Forestry Administration in 2002 (see
“GM trees get lost”, this series).
Several companies, including Weyerhaeuser, Shell and Monsanto, at
one time involved in GM tree research have since pulled out
because it was not economically attractive . However, the
decision reached in December 2003 at the ninth Conference of the
Parties to the UN Framework Convention on Climate Change to allow
Northern companies and governments to establish plantations of GM
trees in the South under the “Clean Development Mechanism”
might be the subsidy that GM proponents need to make GM trees seem
The overriding importance of forests
Forest trees are long-lived. Their root system is extensive,
interacting with countless species in the soil biota that are
crucial for recycling, storing and keeping nutrients within the
Above ground, forest trees provide shelter, home and food for
indigenous peoples and between 1.5 to 2 million species of insects,
birds, mammals, other plants, epiphytes, fungi and bacteria.
All human beings are dependent on forests in one way or another,
for clean water, habitat, food, medicinal plants, and as
recreational and spiritual sanctuaries.
Most of all, forests, especially the tropical rainforests, are
essential for the water cycle that brings rain to crops; and for
regulating the temperature of the earth, preventing places from
getting too hot or too cold. Forests absorb carbon dioxide and
produce oxygen; in that respect they are the ‘lungs’ of the
living earth (see “Why Gaia needs rainforests”, SiS 20).
Losing forests to GM tree plantations would spell ecological
disaster for our planet, especially as global warming is fast
GM trees anathema to forest ecosystems
GM trees are designed for large monoculture plantations anathema
to the bio-diverse natural forest ecosystems. Local people’s
names for industrial tree plantations are revealing .
Eucalyptus is the “selfish tree”, because eucalyptus
plantations remove nutrients from the soil and consume so much
water that farmers cannot grow rice in neighbouring fields.
Mapuche Indigenous People in Chile refer to pine plantations as
“planted soldiers”, because they are green, in rows and
advancing. In Brazil, tree plantations are “green deserts”,
and in South Africa, “green cancer”. Throughout the Global
South, organisations and networks are actively opposing industrial
tree plantations on their land. GM trees will intensity both the
problems of industrial plantations and the opposition from
A joint report by the World Rainforest Movement (WRM) and Friends
of the Earth International (FoEI)  says that the scientists
claiming to “improve” trees by genetic modification are in
reality working to
“improve the profitability of the businesses” funding their
“But from a biological perspective there is no improvement whatsoever. Is a
tree with less lignin better or worse than a normal one? It is clearly worse,
given the resulting loss of structural strength, which makes it susceptible to
extensive damage during windstorms. Is an herbicide-resistance tree an “improvement”?
It is not, for it allows extensive herbicide spraying that affects the soil on
which it stands, at the same time as it destroys local flora and impacts on
wildlife. Is a flowerless, fruitless and seedless tree of any use to living
beings? It does not provide food to myriad species of insects, birds and [other]
species that depend on these as food. Is a tree with insecticide properties an
improvement? It is a dangerous hazard to many insects species, which are
themselves part of larger food chains.”
GM trees violate international conventions
The WRM report points out that GMOs in general and GM trees in particular, are
a clear violation of the Convention on Biological Diversity, which obliges
governments to take a precautionary approach towards GMOs that may cause
serious damage to biodiversity. GM trees also violate the spirit of
the United Nations Forum on Forests, which was set up to protect the world’s
Unfortunately, the inclusion of GM trees within the framework of the Kyoto
Protocol’s Clean Development Mechanism means that the Climate Change
Convention not only supports the expansion of monoculture tree plantations,
but GM tree plantations supposed to act as better “carbon sinks”.
The WRM, FoEI International and ECOTERRA Intl. are calling on all governments,
especially the Parties to the Framework Convention on Climate Change and its
Kyoto Protocol, to ban the release of GM trees. The campaign to ban GM trees
was launched in January 2004 by the Finnish People’s Biosafety Association
and the Union of Ecoforestry (see “No to GM Trees”, SiS 23).
Transgene contamination inevitable and unavoidable
Forest trees are tall, long-lived and produce abundant pollen and seeds that
can be carried far and wide. Forest trees also reproduce asexually, sending
out clones that spread long distances from the mother plant, thus promoting
further transgene contamination. Contamination of native trees by GM trees is
hence inevitable and unavoidable.
Low lignin GM trees increase destruction of forests & livelihoods
Low lignin trees are more susceptible, not only to storm damage but also to
attacks by insects, fungi and bacteria (see “Low lignin GM trees and forage
crops”, SiS 23).
The reduced-lignin trait spreading to native forest trees will make them
susceptible to storm, attack by pests, and fungal and bacterial diseases.
Insect pest populations will also increase as a result.
While low lignin GM tree plantations may benefit the paper industry, they will
destroy local livelihoods, forcing people to move away, some of them to new
forests where they clear more land for farming . Tree plantations often
follow the destruction of native forests. In Sumatra, for example, vast areas
of forests have been cleared to feed pulp and paper mills; the clear-cut
forests being replaced by acacia plantations. The argument that planting
faster growing GM trees is “growing more wood on less land” is misleading.
Producing more fibre for the pulp industry will not change the demand for high
quality decorative tropical hardwoods for the construction industry, which
come largely from native forests.
Also, the demand for timber is not the only cause of deforestation;
road-building, dams, cash crops (such as soya in Brazil and Argentina) or
cattle ranging, mining and oil extraction all contribute to destroying native
forests, and creating GM tree plantations will do nothing to stem the
Fast growing GM trees will consume even more water than current industrial
tree plantations, draining the already depleted aquifers and impacting on
Most of the pulp produced in the South is exported to the North. Per capita
paper consumption in Germany is 70% that in the US. Vietnam consumes on
average 2% of the amount of paper consumed in the US, despite the fact that
literacy rates in the US, Germany and Vietnam are almost identical . Nearly
40% of the paper is used for packaging, and 60% of the space in the US
newspaper is taken up by adverts. According to Jukka Hamala, CEO of Stora Enso
- the second biggest paper, packaging and forest products company in the
world, whose sales totalled 12.4 billion in 2004 -
the key factor in increased paper demand was increased spending on
advertisements in newspapers and magazines. Thus, increasing paper consumption
is neither necessary nor desirable.
Fast growing GM trees exacerbate climate change
The argument that planting GM trees can reverse climate change is also
fallacious. Japanese car manufacturer Toyota started field trials of trees
genetically modified to absorb more carbon in 1993. Unfortunately, while
carbon absorption increased, it was accompanied by a dramatic increase in
Tree plantations are much less effective in sequestering carbon than the
native forest ecosystem. The biodiverse native forest ecosystem is an
effective carbon sink. It has been estimated that the neo-tropical forests of
Central and South America sequesters at least one tonne of carbon per
hectare per year in biomass increase above ground. (It is possible that
additional carbon is sequestered in the soil.) In contrast, destroying a
hectare of forest releases 200 tonnes of carbon (see “Why Gaia needs
rainforests”, SiS 23).
Fast-growing reduced-lignin trees will also rot more readily, returning carbon
dioxide more rapidly to the atmosphere, thereby exacerbating global warming
instead of ameliorating it.
Researchers used a NASA thermal infrared multispectral scanner from the air to
assess energy budgets of experimental forests in Oregon in 1989 . They
found that a clear-cut forest area had a surface temperature of 51.8C, hotter
than a nearby quarry, which registered 50.7C. The Douglas fir plantation with
mature trees registered 29.9C, compared to 29.4C over the natural Douglas fir
forest regrowth; while the coolest temperature of 24.7C was found over the 400
year-old forest. The cooling effect of the natural forest ecosystem is not
only important for alleviating global warming; it is also a significant
indicator of sustainability .
Insecticidal GM trees destroy biodiversity
There is no doubt that the insecticidal GM trees will kill many insects, both
target pest species and non-target species; that is, until the pests develop
resistance within six or seven years, according to the estimate of Liu
Xiaofeng from Henan Agriculture Department, a scientist critical of the GM
cotton planted in China (see “GM cotton fiascos around the world”, SiS25).
At that point, more insecticides will have to be used, especially as new kinds
of pests will have appeared.
The far greater threat to biodiversity is the spread of the insecticidal
traits to natural forests. Laboratory feeding experiments have shown that Bt
toxins produced in GM crops can harm beneficial predators that feed on insect
pests, even when the pests themselves are not affected by the toxins . One
class of Bt toxins (Cry1A) was found to harm butterflies, lacewings and mice.
Another class (Cry3A) acts against insects belonging to the Order Coleoptera (beetles,
weevils and stylopids) , which contains some 28 600 species. Bt toxins are
known to leach out of the roots into the soil, with potentially huge impacts
on the soil biota. Reduction of insect populations will in turn impact on
birds and mammals that feed on insects.
Herbicide-tolerant GM trees make green deserts
GM trees have been made tolerant to broad-spectrum herbicides that kill all
other plants. If that is not bad enough, they are also harmful to all species
of animal wildlife including human beings (reviewed in The Case for a GM-Free
Sustainable World, ISP Report www.indsp.org
). Plantations of herbicide-tolerant GM trees are really green deserts, and
collateral damage to nearby forests and crops from spraying herbicides is
inevitable, as is the pollution of drinking water.
Glyphosate is the most frequent cause of complaints and poisoning in the UK.
Disturbances of many body functions have been reported after exposure at
normal use levels. It nearly doubled the risk of late spontaneous abortion,
and children born to users had elevated neurobehavioral defects. Roundup (Monsanto’s
formulation of glyphosate) caused cell division dysfunction that may be linked
to human cancer. Glyphosate caused retarded development of the foetal skeleton
in laboratory rats. It inhibits the synthesis of steroids and is genotoxic in
mammals, fish and frogs. It is lethal and highly toxic to earthworms.
Glufosinate ammonium is linked to neurological, respiratory, gastrointestinal
and haematological toxicities and birth defects in humans. It is toxic to
butterflies and a number of beneficial insects,
also to the larvae of clams and oysters, Daphnia, some fresh water fish such
as the rainbow trout. It inhibits beneficial soil bacteria and fungi,
especially those that fix nitrogen.
The health hazards of GM trees are common to those of other GM crops, but they
will be exaggerated. Two of these in particular are worth mentioning.
Agrobacterium, used in the vector system for creating many GM trees, is a soil
bacterium that causes tumours to grow on infected plants and is now known to
be capable of transferring genes into animal and human cells (See “Common
plant vector injects genes into human cells” http://www.i-sis.org.uk/Agrobacterium.php).
Scientists have warned that the Agrobacterium is extremely difficult to
eradicate from the transgenic
plants created, and can therefore serve as a potential vehicle for unintended
horizontal gene transfer to soil bacteria and all other species, including
human beings, that come into contact with the transgenic crops. This danger is
greatly increased in GM trees, especially on account of its extensive root
system. The rhizosphere – plant root system - is a known hotspot for
horizontal gene transfer.
The potential of Agrobacterium to mediate horizontal gene transfer, and the
resulting hazards of spreading antibiotic resistance marker gene to pathogens;
creating new bacteria and viruses that cause diseases; and causing cancer in
animals including humans were reviewed in Chapter 11 of
ISP report (www.indsp.org).
Another source of health hazard is the Bt toxins and other transgenes, which
could be spread far and wide in the pollen of GM trees. All Bt toxins used as
transgenes as well as the transgenes conferring glyphosate tolerance were
found to have similarities to known allergens, and are hence suspected
allergens (see “Are transgenic proteins allergenic?” ISIS report 05/01/
1. Lang C. Genetically Modified Trees The ultimate threat to forests. World
Rainforest Movement and Friends of the Earth, December 2004 http://www.wrm.org.uy/subjects/GMTrees/text.pdf
2. Van Frankenhuyzen K and Beardmore T. Current status and environmental
impact of transgenic forest trees. Can J For Res 2004, 1163-1180.
3. Luvall JC and Holbo HR. Measurements of short term thermal responses of
coniferous forest canopies using thermal scanner data. Remote Sensing and the
Environment 1989, 27, 1-10.
4. Ho MW. Are sustainable economic systems like organisms? In Evolution,
Development and Economics (P. Koslowski, ed.), Springer-Verlag, Berlin, 1998b.
5. Dutton A, Klein H, Romeis J and Bigler F. “Uptake of Bt-toxin by
herbivores feeding on transgenic maize and consequences for the predator
Chrysoperia carnea”, Ecological Entomology 2002, 27, 441-7.
6. Wu S-J, Koller CN, Miller DL, Bauer LS and Dean DH. Enhanced toxicity of
Bacillus thuringiensis Cry3A d-endotoxin in coleopterans by mutagenesis in a
receptor binding loop. FEBS Letters 2000, 473, 227-232.
7. Reviewed in Ho MW and Lim LC. The Case for a GM-Free Sustainable World, ISP
Report, ISIS & TWN, London & Penang, 2003.
Dr Maewan Ho is editor of Science in Society (SiS) magazine and scientific
advisor to The Third World Network. For more information on her work
please join ECOTERRA's ANTI-GE caampaign
send an e-mail to AntiGE "at" ecoterra.net
please join the Global Anti-GE-Tree campaign:
No right for contamination
Global Ban on GM trees
pls see also:
Global Justice Ecology Project http://www.globaljusticeecology.org
BioWatch SA http://www.biowatch.org.za
Independent Scientist Panel ISP http://www.indsp.org