|Keywords:||Trees, Genetic engineering, New Zealand, USA, China, Herbicide tolerance, Disease/pest resistance, Risk assessment.|
|Correct citation:||Rautner, M. (2001), "Designer Trees" Biotechnology and Development Monitor, No. 44, p. 2-7.|
With development of genetically modified (GM) trees increasing, they could soon be a feature in the landscape. Trees grow large, live long, and inhabit diverse and complex forest ecosystems. This presents particular implications for genetic modification. Meanwhile commercial enterprises are racing ahead to provide genetically tailored trees designed for plantation use.
"Anyone attempting to grow trees like this should seek medical help. , reads the caption next to a picture of a square tree stump. The company who paid for this advertisement printed in New Zealand magazines is Fletcher Challenge Forests. Scientists who worked on the Human Genome Project were hired by the company to shift their work to trees, which will, they hope, . give us the key to developing a new range of specialist, designer trees that are perfectly matched to customers. needs in terms of strength, density, colour, grain, pattern, and maybe even shape.. Whilst the square tree has not yet been invented, companies like Fletcher Challenge Forests are developing trees that grow faster, are resistant to pests, herbicides, fungi and viruses as well as trees that do not have flowers or cones, or that have different fibre structures and are tolerant to drought and frost.
According to Professor Steven Strauss of Oregon State University, a leading proponent of GM trees, . The ultimate goal of genetic engineering is domestication of trees . making them better suited to growing in cultivated environments of plantations and consequently making them more poorly suited to growing in the wild..
The goal of tree domestication has many implications that challenge current understanding of what constitutes a forest. The differences between a plantation, in which management techniques strive to maintain a monoculture, and natural forests, which harbour twothirds of the known global biodiversity, are marked.
Given the expansive scale of forests and plantations and the critical role that forests play in fostering biodiversity and regulating climate, the discussion about GM trees should include the impact of transgenic plantations on natural forests. Scientists estimate that around one per cent of tropical forest species have been discovered. The complex of symbiotic dynamics between species is even more of a mystery, which makes rigorous risk assessment all but impossible and complicates any study of the effects of genetically modified organisms GMOs on wild forest biodiversity.
In a tropical forest, a single tree may play host to thousands of species. Insects in the canopy attract birds, mammals, reptiles and amphibians. Epiphytic plants, climbers, lichens, mosses and fungi cling to branches and gain nourishment from them or from falling leaf matter. They attract fauna to create micro-ecosystems. Birds and animals feed from leaves, fruit and flowers and myriads of insects live off the wood. The roots in the soil are equally alive with insect life and mycorrhiza, which play a vital role in supplying nutrients such as nitrogen to the tree. The dynamic dance of life continues even when the tree dies, its wood becoming a home, breeding ground and important source of food. The array of species presents the most complex interaction of life on earth, unmatched by any other ecosystem.
Maintaining the biological integrity of forest ecosystems, whose importance we appreciate but do not as yet understand, presents difficulties to researchers currently developing tree . products. for the many companies that have expressed interest in exploiting them.
Fletcher Challenge Forests is not the only company that is involved in developing GM trees. In the USA alone, more than 120 field trials including trials with fruit trees have been approved over the past decade, the majority of them in the last two years. Even though commercial GM plantation trees are not likely to be seen for at least two years, field trials are underway in a variety of countries including Chile, Indonesia, South Africa, New Zealand and China, as well as in several European countries. Currently the majority of the trials focus on three major plantation species: poplar, radiata pine and eucalyptus.
In April 1999, Fletcher Challenge Forests joined with New Zealand. s biotech research corporation Genesis and USA forest companies International Paper and Westvaco to form ArborGen. This US$ 60 million joint venture is the biggest of its kind working on GM trees. Life science company Monsanto was also involved in the project but later dropped out citing . strategic business. reasons
The Tree Genetic Engineering Research Cooperative (TGERC), based at Oregon State University in the USA is also doing research and runs many of the USA field trials. Its members represent a wide range of institutions involved in research into GM trees. They include governmental institutions like the USA Forest Service and Department of Energy, multinational forest companies like Weyerhaeuser and International Paper, energy organizations like the Electric Power Research Institute, as well as universities like Washington State University and the University of Washington.
International Paper, largest wood products company in the world and one of the ArborGen partners, says that . Biotechnology clearly offers the potential to improve the sustainability of the earth for a population soon to be eight to ten billion people.. Indeed the United Nations. Food and Agriculture Organization (FAO) has projected that if consumption of forest products does not change, there will have to be an annual increase of between 1.1 per cent for pulp and 2.4 per cent for paper and paperboard to meet current market trends.
According to the industry, GM tree plantations are required to meet growing global wood demand. Furthermore, they argue that increasing population pressure poses a threat to the last remaining ancient forests and this would be alleviated if wood supplies were met through GM plantation forestry. Producing GM trees tailored to the consumer will have environmentally friendly spin-offs. However, as more research and development (R&D) information emerges sceptics are increasingly questioning the industry. s claims. <
As with other GM crops, development of herbicide tolerance remains a favourite in trees. The risk of the spread of herbicide resistance in sexual progeny is currently an area of research priority as Dr Strauss has stressed: . I strongly agree that this is a concern, and should be studied in detail in areas of intended release.. Whilst the effects of the spread of resistance to wild populations remains uncertain, other implications of herbicide resistance in plantations are more obvious.
Application of herbicides to plantations which often number thousands of hectares is problematic, with spraying from the air the most efficient option. With agricultural crops, increased use of herbicides such as glyphosate on herbicide resistant crops has been widely documented. A corresponding increase when applied to large areas of plantation inevitably increases human and environmental exposure to the chemicals. Furthermore, widespread eradication of undergrowth leads to a host of environmental problems, from loss of species habitat to erosion and soil leaching.
An experiment by the Chinese Institute for Forestry to make poplar resistant to specific insects by introducing a Bacillus thuringiensis (Bt) gene showed how the same genetic modification can have very different impacts. After undertaking the same modification, three different changes were identified. In the first group, the inserted gene could be identified but the trees were still affected by the insects. The second group, though insect resistant, showed changes in the production of chlorophyll, leaving the leaves more yellow and smaller than usual. Only the third group was resistant to the insects and grew normally. Nevertheless, some trees of this group were attacked two years later by insects that were previously unknown as a pest in unmodified poplar trees. These results show that the process itself is inaccurate and unpredictable and that possible unintended side effects might occur years later and remain undetected for decades.
The longevity of timber cropping cycles and the natural role of trees as host to diverse insect colonies are two areas of concern. Release into the environment would expose countless living organisms to the Bt toxin for years, with unpredictable consequences. Pollen from trees that are insect resistant could pass on resistance to offspring of related species. A spread of insect resistance throughout forest ecosystems would be disruptive to insect communities and the complex dynamics within the wider forest ecosystem.
A major concern for all users of Bt is an anticipated build-up of resistance by target insect populations, making the toxin useless as a pest control agent in future. A factor currently under close scrutiny is whether the pattern of resistance is accelerated by use over a wide area of monocrop. If as some suspect this is the case, then industrial tree plantations covering vast land areas maybe an inappropriate application of the technology.
Trees are the oldest and largest living organisms on the planet and some concerns are more specific to them than other GM crops. Trees are in the ground for longer and spread their pollen more widely than agricultural crops. For example the pollen of pine trees can be windblown for up to 1000 km and still maintain its ability to germinate. To allay concerns of GMOs spreading to the wider environment, scientists are exploring sterility technologies. Sterility traits are useful to companies as they restrict unlicensed use of commercialized GMOs. In the case of trees, sterility technology is also being explored to increase growth rates. Trees produced with no reproductive organs are designed to transfer growth to the wood fibre.
There are concerns that if a tree does not have flowers, pollen or cones it could deprive flora and fauna of important food sources. Monoculture plantations already encourage a great loss of biodiversity. Nevertheless, a few native animal species have found refuge in plantations as the best available habitat after native forests have been destroyed. Adaptable species have become dependent on plantations for food. In Sri Lanka, only three species of bird have been observed in pine monocultures, five in eucalyptus plantations but 25 in natural forests. Sterile GM plantations could have negative impact on these species by further depriving them of food.
Trees use complex reproductive methods to ensure propagation. Though experiments have achieved some success in limiting these, none have totally eliminated the risk that the tree will ensure reproduction. Some trees such as poplar, for example, rely on wind blown foliage to take root. Whilst on the one hand non-sterile GM trees risk spreading traits into the wild, on the other, there are concerns about the impact sterile trees would have on the environment. So far, true sterility technology remains elusive, so risk of gene flow to the wild remains.
As with agricultural crops there is also the danger of horizontal gene transfer, meaning that the new gene is passed on to unrelated species in ways other than by natural propagation. According to Terje Traavik, in a witness statement given to the Royal Commission of Inquiry on Genetic Modification in New Zealand 2000, . gene constructs that are introduced into species always carry a vector gene to make the transformation possible. Vectors are specifically constructed to break species barriers. They could pick up and transfer genes from new host organisms. Such newly created genetic mosaics may then become transferred to new species, or recombine between them to result in pathogenic viruses. There is no way to interfere once a horizontal gene transfer cascade has been initiated.. An example of horizontal gene transfer was discovered by Professor Kaatz, who found that a gene in GM canola transferred to the gut bacteria of bees who had fed on the crop.
The prediction and assessment of effects other than the engineered trait are virtually impossible. First, a single gene can affect more than one phenotypic character, and second, the genome of trees is extremely large. For example the genome of the Radiata pine is eight times larger than the human genome.
Researchers at the German Federal Research Centre for Forestry and Forest Products developing GM aspen trees were allowed to field trial them under the proviso that any flowering that occurred would be removed by hand. They were amazed that some of the trees started flowering after three years which is some four years earlier than aspen in Germany would usually flower. The same field trial encountered another phenomenon known as gene silencing. Gene silencing occurs when the organism switches off the trait of the inserted gene. The phenomenon is more likely to occur in trees because of their long growth cycles. Trees are in the ground for many years and exposed to many environmental stress factors like drought, frost, wind and fire. These stresses can trigger gene silencing so trees may react by turning off some of their genes. About 2 per cent of the German aspen that were designed to express a change in their leaf shape reverted back to their natural growing form. This could happen years after the tree was planted making monitoring for negative traits of individual trees in a large plantation all but impossible.
While there are a number of USA, New Zealand and European companies involved in the development and field testing of GM trees, the first commercially planted GM trees will most likely be seen in countries where the climate allows for short rotation times for plantation trees. Most of these countries are in the developing world, for instance Latin America or Southeast Asia. This creates a situation of exporting risk from industrialized countries, where the technology is created, to developing countries in the South where the local environment, communities and economies will be exposed to the potential risk. The New Zealand Forest Research Institute, for example, has developed GM trees resistant to the European shoot moth for the GenFor joint venture and then shipped them to Chile where they are being released in a field trial with a view to commercialization there. GenFor is a joint venture between USA company Interlink Biotechnologies, Canadian firm Cellfor and Santiago based Fundacion Chile.
The UN Kyoto protocol on climate change requires that industrialized countries reduce their carbon dioxide emissions by agreed targets. Industrialized countries such as the USA, Australia, Canada and Japan argue that carbon stored in forests and plantation schemes at home and abroad should be counted under the targets. Others such as the European Union contend that if this were to happen, industrialized countries would merely offset industrial fossil fuel emissions with forest projects and evade the difficult political choices required to shift away from reliance on fossil fuels.
Provisions in the protocol called the . flexible mechanisms. could allow countries to offset their emissions by investing in plantation forestry in developing countries, which some countries argue provides storage for carbon so creating a carbon sink. Governments and corporations investing in such schemes would be rewarded with internationally tradable . carbon credits.
The proposal of giving credit for carbon sinks has received criticism from a number of quarters. The central argument is that managed forests cannot be considered as long-term carbon stores if they are cut for consumer use. Industry representatives meanwhile argue that paper in waste dumps provides a useful carbon storage facility. Forest sinks would encourage maximization of carbon storage in plantations to reap higher credits. According to the World Rainforest Movement, obvious routes to achieving such a goal would include larger-scale plantations using trees with faster growth rates.
Companies such as Toyota together with Mitsui and Nippon paper have created Afforestation Ltd., a company that intends to plant up to 5000 hectares of eucalyptus plantations in Australia. All three companies run their own biotechnology centres or are in possession of patents on GM trees. Toyota has field-tested GM trees that absorb more carbon dioxide, but has since dropped the tests citing inefficiency as the reason for doing so. Environmental groups fear that transgenic trees will be widely encouraged under the Kyoto protocol if they are not actively excluded.
While there is an increase in the demand for forest products, the market is undergoing a substantial change. An increasing number of consumers want to make sure that the products they are buying are not coming from ancient forests, but rather from sustainable, well-managed forests. The market has reacted to this by introducing third-party certification and labelling. The Forest Stewardship Council (FSC) is an international non-profit organization that promotes environmentally appropriate, socially responsible and economically viable management of forests, and has recognized the imminent threat of GM trees to biodiversity. In its Principles and Criteria it states that the . use of genetically modified organisms shall be prohibited.. The FSC will also not certify any forest containing field trials of GMOs.
Recently the world. s largest furniture retailer IKEA (Sweden) made a commitment to source its products from FSC certified forests, as have USA based Home Depot and Lowe. s. Retailers that together sell more than a fifth of all wood used in America. s home remodelling market are committed to the FSC. It is estimated that the annual turnover in forest products of companies that give preference to the FSC exceeds US$ 25 billion.
. A key goal of genetic engineering in forestry is to increase productivity of short rotation tree plantations to enable the growing world demand for wood products to be met while large areas of natural forests are reserved from intensive harvesting. , states the Tree Genetic Engineering Cooperative (TGERC).
However forest companies have often failed to counter the argument that it is not necessary to log ancient forests in order to supply the world with wood products. . Re-Source. , a Greenpeace report, lists ways to shift away from timber from ancient forests to alternatives. Already 7 per cent of all paper worldwide is derived from fibres other than trees, including sugar cane waste, bamboo, hemp and flax. Straw, for example, also offers the potential for cheaper paper production. Newsprint accounts for around 13 per cent of global paper use. It is possible to recycle newsprint five times with little change in fibre quality. Yet the average recycled content of newspapers in the USA today is only 28 per cent.
Because trees have long rotation cycles and because, unlike food crops, they have not been crossbred over centuries, there is considerable potential for improving the yield of trees through traditional breeding. Despite proponents. claims that GM is necessary to speed up tree breeding, a subsidiary of Scandinavian forest product giant Stora Enso claims to have increased the productivity of their trees by 70 per cent within eight years without using any kind of genetic engineering technology.
Environmental groups like Greenpeace are calling for a ban on GM trees because of the impacts GM experiments have on plantation and wild ecosystems. While companies such as International Paper, Westvaco and Fletcher Challenge Forests say that to meet the increasing demand for wood fibre it would be necessary to introduce genetic engineering into forestry, other companies like Stora Enso have already decided to refrain from the commercial use of controversial genetic engineering techniques on trees or any other organisms. In its Environmental Report for 1999, Stora Enso states that . The fundamental issue is that genetic engineering modifies the very . code of life. through an artificial, asexual process. We must ask ourselves whether we have the right to do such things to ourselves and to other living things. Economic and social systems may also be threatened when fundamental biological processes are interfered with..
| Genetically modified trees and their traits
(number of field trials 1988-2000)
Data from field trials not always disclosed to the public, so some figures may be missing. Note that in some trials two or more traits are introduced so that the total amount of field trials is in fact lower. About half of the trial sites are in the USA.
¹ Most insect resistance is reached through the introduction of a gene of Bacillus thuringiensis.
² Other traits include fungal resistance, salt resistance, male and female sterility, reduced ethylene production, altered flowing, faster growth and other undisclosed traits.
³ Eucalyptus sp. includes E. camaldulensis, E. globules and E. grandis.
&sup4; Picea sp. includes P. glauca and P. mariana.
&sup5; Pinus sp. includes Pi. radiata, and Pi. sylvestris.
&sup6; Populus sp. includes Po. deltoids and Po. nigra.
Owusu, Rachel Asante (1999), GM technology on the forest sector. World Wildlife Fund http://www.wwf.org
Ewald, D. and Han, Y. (1999), FReisetzungsversuche mit transgenen Pappeln in China. Freisetzung transgener Gehözer, Tagungsband, Berlin.
New Zealand Royal Commission on Genetic Engineering: http://www.gmcommission.govt.nz
Stora Enso Environment Report:http://www.storaenso.com
Forest Stewardship Council Principles and Criteria: http://www.fscoax.org
Greenpeace fact sheet on GM trees: http://www.greenpeace.org/˜geneng/reports/gmo/pulpfiction.pdf
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