Awareness that Britain is a rainforest nation is finally growing. Environmental organisations are doing their best to get Britain’s rainforests the recognition they deserve. But one man, Guy Shrubsole, has taken on the mission of bringing ‘Atlantic rainforest’ to wider attention. If you are unfamiliar with the idea that we have rainforest you should read The Lost Rainforests of Britain by Guy Shrubsole. In this passionate and well-researched book Guy introduces us to what defines our rainforests, where they grow, why they are special and how we can recover them from a position of near complete loss.

In Scotland the Atlantic rainforests are found near the west coast. These unique and special places drip with lush green mosses, liverworts, lichens, ferns and even a highly specialised parasitic fungus. This rich assemblage of species, that far exceeds the diversity of Britain’s native flowering plants, uses the trees as a surface to grow on, creating miniature worlds suspended in the air. This ‘piggyback’ lifestyle, where plants grow on plants, creates trees that appear weighed down and hidden by a luxuriant green covering. The plants involved are the so-called ‘epiphytes’ and they are the telltale indicator of rainforests all over the world.

Of course, Scotland’s rainforests grow in cool humid conditions and are what we call temperate rainforests. This type of rainforest is vanishingly rare in comparison with the more familiar tropical kind. But temperate rainforests do crop up in some widely separated places, for example, Chile, Japan, Tasmania and New Zealand to name just a few. In Britain, the Scottish examples are some of the wettest that we have and annual rainfall can exceed 3m. A critical factor for these rainforest communities is that rain is distributed throughout the year. This means the plants can get all the moisture they need from a combination of rain, fog and high humidity in what are generally sheltered conditions.

Some extraordinarily rare organisms are found in Scotland’s Atlantic rainforests. The hazel gloves fungus is associated only with hazel and is thought to be a parasite of another wood-rotting fungus – a case of fungi eating each other. Killarney fern is so rare that the detailed information on its whereabouts has been removed from the public domain and can only be accessed by a few select botanists.

It is not only certain associated species that are rare. The remaining fragments of rainforest have a combined area that has been estimated to cover less than half a per cent of the British mainland. To put that figure into perspective, studies have shown that the area with suitable climate for rainforest – the Atlantic rainforest zone – accounts for about one fifth of Britain, spread right down the western side of the island. Mapping this past (and potential) rainforest area has been pioneered by the Garden’s lichenologist Chris Ellis.

The loss of almost all our rainforest is a legacy of felling of trees and introducing livestock that goes back to early human settlement. The extermination of the natural predators of red deer – wolf and lynx – allowed deer numbers to expand and natural regeneration of forest is now prevented in all but the most inaccessible places and in areas where deer fences have been installed. The losses being in the dim and distant past has meant that we have forgotten we ever had rainforests in the first place. This is another example of what ecologists call ‘shifting baseline syndrome’.

I was moved to write this post as I was recently reminded that wych elm (Ulmus glabra) is an overlooked rainforest tree. It is not exclusive to rainforests, but then none of our rainforest trees are only found in rainforests. If you read about our rainforests, you could easily get the impression that they are dominated by oak and hazel. However, there are many other bit part players and elm is one of them that appears when the soils are more lime-rich. Even Guy Shrubsole’s excellent book about rainforests gives no mention of rainforest elms.

The other reason for writing this is that wych elm is one of ten focus species in the Garden’s Scottish Plant Recovery project, supported by a Nature Restoration Fund grant from NatureScot. Information on why wych elm was chosen and what we are doing to recover the species from the serious impacts of Dutch elm disease can be found in earlier posts – Next gen elms and Plants moving on.

Fieldwork to study elm genetics for the Scottish Plant Recovery project, conducted by Euan Bowditch, currently on a fellowship with the Garden, was another reminder that elms grow in rainforests. Euan told me of his experience in elm dominated coastal woodland in Uig on the Isle of Skye this summer during one of his sampling trips. Woodland ecologists have not generally recognised elmwoods, so Euan’s impression that this is a local type of rainforest is interesting.

More recently, our partners in Assynt in northwest Scotland have sent incredible images of rainforest elms on limestone rock outcrops around Inchnadamph. This area is currently free of Dutch elm disease, but the disease creeps ever closer and is now established around Ullapool to the south. Mandy Haggith, a poet and writer living in Assynt, is campaigning to raise awareness of the wych elms and the threat that they face.

The images in this post have been supplied by Chris Puddephatt who took them on a series of walks after hearing about the elms plight. Chris’ images beautifully capture the gnarled and evergreen nature of so many Atlantic rainforest trees. You can read about his walks and see some more of his pictures in his own blog post.

The Scottish Government is currently working on targets for Atlantic rainforest recovery associated with a reduction in deer numbers in key areas. This is a potentially exciting time for initiatives that want to encourage the natural regeneration of these jewels in the crown of British woodland. There is very little need to plant any trees as they will plant themselves very effectively if we reduce the grazing pressure that is holding back the recovery.

The Garden’s work on wych elm will contribute to the recovery. We are working with the genetic resource of trees showing good signs of being resilient in areas that have had Dutch elm disease for more than 40 years. Using these trees as the parents of a new generation of seedlings we can move potential resilience to other parts of Scotland, including places yet to be hit by disease. What we know is that when disease does arrive almost every mature elm will be lost. Our work on elm holds out the possibility of getting ahead of the disease. The long-term aim is for natural regeneration and repopulation of regions, like Assynt, that are suitable for elm. Our actions are a helping hand to get things going. Natural spread and local adaptation are the long-term solutions.

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Acknowledgement: Thanks to Chris Puddephatt for agreeing to share his images of elms. Chris was able to locate a selection of elms in Assynt thanks to the work of Ian and Pat Evans that culminated in The Flora of Assynt.