30 Jul 2018

For over 200 years, botanists have known about a strange tree growing at Castell Dinas Bran near Llangollen.  The plant first described in Hudson’s Flora Anglica in 1798 was recorded to be growing out of the castle walls and looked a bit like a whitebeam.  Botanists were confused about what it might be and gave it several different names!

A descendant of that tree was removed from the castle in the 1990s to prevent damage to the historic castle walls.  The rescued tree was planted in a private garden and almost forgotten until 2016 when we became involved. We undertook a rescue project to remove the tree from the garden and brought it back to Chester Zoo where the idea for a conservation project grew.

Endemic to the limestone crags of the Eglywyseg escarpment in Denbighshire, the Llangollen whitebeam is an extremely rare tree which before our project was carried out had an estimated total population of 250 individuals. The last survey for the species had been done in the 1980s and our experts decided it was about time to conduct a resurvey to better understand the conservation status of this special tree and assess if any action was needed to ensure the survival of the rare species.

Sarah Bird, Biodiversity Officer – UK and Europe explains:

“Having a rare endemic tree growing so close to the zoo is really exciting.  With only around 250 Llangollen whitebeam trees existing anywhere in the world, this is one of the rarest species Chester Zoo works with.  Botanists Tim Rich and Libby Houston, who are whitebeam experts, came to record all the trees on the crags.  The Llangollen whitebeam is very similar to some other British whitebeams so we had to get the best people to do the survey.”

The full survey took place in 2017 and the team actually found 300 trees, showing that the population appears to be stable despite some threats from the invasive and non-native Cotoneaster species. Our work has resulted in an update of the species’ IUCN Red List status and measures have been taken to tackle the Cotoneaster.

In parallel with the field work, the Horticulture and Botany team at the zoo have been busy propagating Llangollen whitebeams. We have used seeds from the Millenium Seed bank at Kew and some collected from the crags, and we are thrilled to have 50 young trees in cultivation at the zoo!

Richard Hewitt, Team Manager Nursery adds:

“It is great that the nursery team are using their expertise in propagation and growing on of locally threatened native trees here at Chester Zoo.  Our aim is to grow on 100 trees of Llangollen whitebeam.  When they are large enough, some will be planted near Castell Dinas Bran and the rest will go into public gardens in the region where we can tell people about this incredibly rare tree.”

The project is now focussing on raising awareness of this rare species in the local area. A few of the young trees will be returned to a safe spot near castle Dinas Bran. We will also be providing specimens for local public gardens accompanied with signs explaining the importance and curious history of the tree.

The limestone cliffs where this tree grows are really amazing. You can see them and meet botanist Tim Rich in the short film here.