UK bans sweet chestnut import to protect native trees from fungal blight

Imports of sweet chestnut trees from areas affected by a fungal blight will be banned to prevent a repeat of the disease that is devastating the UK's ash population.

Sweet chestnut blight (Cryphonectria parasitica) is usually fatal and killed 3.5bn trees in 20 years across Europe and northern America, where it was first detected in the 1930s. There are an estimated 44m sweet chestnuts (Castanea sativa) in the UK.

The environment secretary, Owen Paterson, indicated in May he would like to implement the ban to prevent infected saplings reaching the UK, and on Friday confirmed they will be banned before the end of September.

"I'm taking action to protect our sweet chestnut trees by bringing in rules to ban the import of trees from areas in Europe where they have sweet chestnut blight ahead of the planting season," he said.

More than 18,000 sweet chestnuts were imported to the UK in the first four months of 2013.

The blight was detected in the UK in 2011 in about half of 300 trees planted for nut production in Warwickshire and later at a site of 30 trees in East Sussex. All the trees were subsequently destroyed.

The Country Land and Business Association and Horticultural Trades Association welcomed the import ban.

Sweet chestnut blight is one of the diseases on a new risk register of diseases and pests threatening the UK's trees and plants, which is in the process of being setup after the recommendation of an independent tree health taskforce.

The government has admitted that ash dieback, which was found in the UK last year, cannot be stopped and the most that can be hoped for in the short and medium term is to slow the spread of the fungus that causes it.