They will soon be able to transfer genes between tree cells to make them resistant to diseases which can wipe out native species. Earlier this year, experts warned that another favourite English tree, the common oak, is dying at an alarming rate as a result of a mystery unexplained disease.
The technology is being developed by conservation-minded scientists but the multinational companies involved with GM crop production are also looking to work with trees. Yesterday, Friends of the Earth warned that modifying trees could be an environmental disaster, with the big companies using the technology to create vast plantations of high-yield trees for the timber industry.
Conservation scientists are carrying out pioneering work on the black poplar, which is so rare that scientists know the exact location of each tree. They are gathering cuttings from the tree, one of Britain's oldest species, dating back more than 10,000 years. The cuttings are stored in a "clone bank" of genetic information.
Initially, the clone bank will be used to grow and reintroduce a wide diversity of trees in Suffolk. If this works, as they are convinced it will, planting could start anywhere in Britain.
They will carry out DNA analysis on the cuttings to identify as many different individuals as possible in order that they can seed trees with a greater genetic diversity.
Friends of the Earth are not impressed. "Companies are already exploring the creation of trees that grow faster and that are resistant to insects," said Sarah Tyack, forest campaigner for FoE. "GM crops have huge implications for biodiversity and this will only be exacerbated if we have GM trees grown en masse. Trees take longer to grow than crops so have longer to cause genetic pollution."
The black poplar, which leans drunkenly over rivers and streams in lowland Britain and is identified by its heavily ridged dark bark, was a favourite subject for the landscape artist John Constable. But today, numbers have fallen to around 7,000 across the country and in Suffolk a third of the recorded black poplar trees have been lost, as its habitat of damp mud on riverbanks has been largely obliterated by the destructive canalisation of rivers.
The problem has been exacerbated because the black poplar can be male or female but not, like many trees, both sexes at once. Most of the surviving individuals are male, possibly because the white woolly seeds produced by female trees have been considered messy so fewer female trees are planted. As a result, the only way a tree can reproduce itself is as a clone from a fallen branch, meaning that several individuals on a river could be genetically identical, increasing their vulnerability to disease.
"The DNA work is critical because it will allow us to get more trees planted," said Sue Hooton, ecologist with Suffolk County Council, who is chairing the project. "The existing poplars will disappear by the end of the next decade and we have to do the DNA programming because otherwise we could be planting hybrid trees all over the palace."
DNA-profiling of trees has traditionally been difficult, according to Dr Keith Kirby, forestry and woodland officer with English Nature, which is part-funding the project. "Trees present more problems than animals and other plants because they have tougher cell walls and it is difficult to extract the DNA for analysis," he said.
"It is good to have a genetic mix among trees in case you get a serious disease. If you have trees of one genetic type then if a disease appears, every tree will be susceptible. If you have a mixture of genetic composition there is a chance one or other will be more resistant," he added. Dr Kirby says Dutch elm disease is a clear example of how genetic modification can be beneficial. "Other species of elm are relatively resistant to Dutch elm disease so it would, in theory, be possible to try and isolate that gene and introduce it to the English elm."