(AP)—Britain's government will start banning the importation of ash trees on Monday to stop the spread of a disease that has killed many such trees elsewhere in Europe.

The ban aims to stop the spread of the chalara fraxinea , which damages leaves, branches and roots, and can kill young ash trees very quickly. The disease has wiped out up to 90 percent of ash trees in some parts of Denmark, and is becoming widespread in central Europe.

The disease was first detected in the U.K. in a nursery in February, on plants that originated from a supplier in the Netherlands. Since then it has been found in woodland and around Britain, and 50,000 have already been destroyed, Environmental Secretary Owen Paterson said.

Movement restrictions also will be introduced along with the ban to try to prevent the disease spreading to areas of the country not yet affected, the official said.

Ash makes up about 30 percent of the U.K.'s wooded landscape, and experts say that its demise could put the survival of dozens of at risk.