Wednesday, September 5, 2012
Alien invaders are threatening trees
Species ranging from the ecologically important oak trees to ornamental varieties are all at risk, from diseases which are now becoming established in Britain, the Forestry commission warned.
Millions of trees are at risk, with oak trees largely suffering from a fungal disease called ash dieback, which was found in a consignment of trees imported from Holland in November last year.
It has already infected 90 per cent of the oaks in Denmark, and could blight the trees in Britain if it gets into the wild.
When 2,000 infected trees were sold in the UK last summer, officials had to track down the owners and destroy the trees to minimise the risk.
Being an island has helped the UK previously - but that advantage comes at a cost - for if a disease becomes a fixture, it has no 'natural predators' to control it.
Hugh Evans, head of Forest Research in Wales, told the BBC: 'The fact that we are an island has helped us, because we are fairly impoverished compared with the European mainland.
'So even the 20 miles of water is enough to protect us from the pests that are quite dangerous on the mainland.
'[But] if pests do get through, then they arrive without the spectrum of natural enemies and that is one element that can make the effect within the arrival country much worse than in the country of origin.'