Why are Ash Trees being imported to UK anyway?

TV news is now reporting that, due to the discovery of Chalara Fraxinea virus (commonly known as ash dieback) in the UK, imports of Ash trees will be prohibited from Monday.  The fungal disease was first found in trees imported from Holland in November last year.  Why the long wait?  Shouldn't this discovery have led to an immediate lock down on imports of any vulnerable tree species?  Australia seems to manage to protect its borders pretty effectively so I'd have thought a small island nation like ours shouldn't find it difficult to do the same in these circumstances.

This disease could be a serious concern to our 80 million ash trees.   This king of firewoods is such an established native of this country that readily self-seeds and grows away so rapidly it's hard to understand why we need to import saplings started in a different country and climate.  It's accepted wisdom that plants will establish better if they're germinated and start their life in the same environment and climate as that in which they'll spend the rest of their lives, and it makes environmental sense.

When we planted 5 acres of mixed native woodland at Muddy Carrot HQ in February 2011 the trees came as bare root stock from a supplier barely 20 miles away.  Of the 2,000 or so trees we planted about 40% were Ash, intended to be coppiced for firewood in the fullness of time so our lives could be lower impact.  They've spent the last two growing seasons getting their roots down, and from next year we expect to see some decent top growth.  I just hope and pray that as a nation so affected by Dutch elm disease in the latter part of last century, we'll act quickly and decisively in the face of this new threat.

If you are concerned about any tree near you you can check the symptoms against http://www.forestry.gov.uk/chalara .