The world's most extensive collection of apple trees, the National Fruit Collection at Brogdale in Kent, is currently being replanted.
The task is undertaken every 25 years to ensure the continuing health of the collection, which consists of 2,200 different varieties, some dating back to the Middle Ages.
Tim Biddlecombe, managing director of the collection's curator, the Farm Advisory Services Team (FAST), said: "This is a mammoth undertaking that we have been planning for two years and will see two trees for every variety planted and recorded.
"The existing collection is more than 35 years old and needed replanting to ensure that we have the correct varieties and to preserve the trees' health and quality."
Leaving the trees in place would render them increasingly prone to pests and disease, he explained. "Commercial fruit growers take a similar approach but they typically replant every 15 to 20 years. The old trees will be kept until we can be certain that the new ones are true to type."
The work, which will take a team of four people about a fortnight, has been helped by the mild weather, he added. The current apple collection will remain in place for a number of years and will continue to be open to the public for tours from the spring. Guided tours of the new apple collection will be available later in the year.
"Alongside the repropagated trees we will also be bringing in a range of new accessions, including material with traits such as disease resistance and tolerance to low winter chilling that will further strengthen the collections. We're extremely pleased that Defra is supporting the repropagation."
Dr Matthew Ordidge, Research Fellow, School of Biological Sciences, University of Reading