The Tree Register, or more fully, the Tree Register of the British Isles (T.R.O.B.I.), is a registered charity collating and updating a database of notable trees throughout Britain and Ireland. It comprises a computer database with details of more than 150,000 trees.

It contains data from the original hand-written records of the late and internationally acclaimed dendrologist Alan Mitchell

Alan Mitchell

Alan F. Mitchell was a British forester, dendrologist and botanist, and author of several books on trees.He almost single-handedly measured every notable tree in the British Isles, founding the Tree Register of the British Isles , which held records of over 100,000 individual notable trees at the...

, and other historical records taken from reference works going back more than 200 years. Recent height and girth measurements can be compared to those recorded by the likes of Loudon

John Claudius Loudon

John Claudius Loudon was a Scottish botanist, garden and cemetery designer, author and garden magazine editor.-Background:...

 (1830s), Elwes

Henry John Elwes

Henry John Elwes, FRS was a British botanist, entomologist, author, lepidopterist, naturalist, collector and traveller who became renowned for collecting specimens of lilies during trips to the Himalayas and Korea. He was the first person to receive the Victoria Medal of the Royal Horticultural...

 and Henry

Augustine Henry

Augustine Henry was an Irish plantsman and sinologist. He is best known for sending over 15,000 dry specimens and seeds and 500 plant samples to Kew Gardens in the United Kingdom. By 1930, he was a recognised authority and was honoured with society membership in Belgium, Czechoslovakia, Finland,...

 (early 1900s) and the Hon. Maynard Greville (1950s), providing a valuable record of growth rates. The Tree Register was one of the founders of the Ancient Tree Hunt

Ancient Tree Hunt (UK)

The Ancient Tree Hunt is a campaign by the Woodland Trust. It seeks to catalogue all veteran trees in the United Kingdom and Northern Ireland. To date over 50,000 trees have been recorded; by 2011 it is projected to have grown to at least 100,000. It is hoped that it will allow a better...

campaign.