New species of tree discovered on Arran
A new species of tree that grows nowhere else in the world has been found on the Isle of Arran.

The unique discovery is a result of a major research project by Scottish Natural Heritage (SNH), Dougarie Estate and the Royal Botanic Gardens in Edinburgh. Two specimens of the newly named Catacol whitebeam (Sorbus pseudomeincichii), a cross between the native rowan and whitebeam, have been found on the island. The new discovery brings the total number of tree species unique to Arran to three.

Graeme Walker, Area Officer for SNH explained: “It has long been recognised that one of the botanical highlights of Arran are the endemic whitebeam trees. These are unique trees which are native to Arran and not found anywhere else in the world. But the recent investigations into the genetics of the trees with the University of Bristol have shown that the population is much more diverse than previously thought.

“We knew about the Arran whitebeam and the cut-leaved Arran whitebeam, which are also crosses between rowan and different species of whitebeam, but it has been really exciting to discover a completely new species. It is very complex picture but we think that the Arran whitebeams are gradually evolving towards a new type of tree which will probably look very similar to a rowan.

“So far our surveys have only been able to find two individual specimens of the Catacol whitebeam, so it is extremely rare and pretty vulnerable. Most of the Arran whitebeams, including the new species, are found in the mountains around Glen Catacol and Glen Diomhan at the north end of the island.”

To ensure the long term survival of the trees, a team from the Edinburgh Royal Botanic Gardens has been collecting seeds and cuttings. These will be grown on in a nursery in Edinburgh so that they can be reintroduced to the wild if ever needed.

Back on Arran, Dougarie Estate and SNH are working on the conservation of the wild trees. To encourage seedlings to grow into mature trees, away from the cliff faces where they are currently found, the deer fence that currently surrounds them will be extended. This will give the trees the chance to increase in numbers by protecting them from grazing deer.

The materials for the new fence will be flown in on Monday 18th and Tuesday 19th June, when the Glen Catacol path to Loch Tanna and Gleann Diomhan/Loch na Davie will be temporarily closed for public safety.

Graeme Walker added: “As the fences are in a very remote area, the fencing materials will be flown in by helicopter. For safety reasons, we are asking walkers to avoid using the Glen Catacol and Glen Diomhan paths during the period of the helicopter lift. We appreciate their patience while this work is carried out.”

Notes for Editors

Free pictures of the Catacol whitebeam and a close up of the leaf attached to covering e mail for one-off use. Please credit SNH.

Arran whitebeams It was previously thought that the Arran whitebeam was a simple hybrid between the rock whitebeam and the native rowan, and that the cut-leaved Arran whitebeam was a back-cross between the Arran whitebeam and rowan.

However the recent research has shown that these crosses have not been one-off events and that further back-crossing has also taken place. The view now is that the Arran population is best thought of as a complex of hybrids. These seem to be gradually evolving towards a new type of tree which will probably look very similar to a rowan.

The Catacol whitebeam (Sorbus pseudomeincichii) is thought to be one of these hybrids. As it was clearly different from both the parent species it has been recognised as a species in its own right.

Scottish Natural Heritage is the Scottish Executive's statutory advisor on the conservation, enhancement, enjoyment, understanding and sustainable use of the natural heritage. Visit for more details.

For further information on SNH, please visit our website at

Further information is available from Nancy Fraser, Press and Public Relations Officer West Scotland Tel: 0141 951 4488 mobile: 07787 856947 E mail:

For Gaelic media inquiries contact Shona MacLellan, Gaelic Communications Officer Tel: 01463 725038 e mail: