The Wildlife of Scotland’s rainforest

What trees will I find in Scotland’s rainforest? 

Around 60 different species of native trees and shrubs can be found in Scotland’s rainforest, but no specific mix of these makes a wood a rainforest. That’s because it’s not trees that define this habitat, but the climactic zone they’re growing in, and the indicator species found there. 

Every woodland within Scotland’s rainforest zone is unique, because each one is not only a reflection of a specific geography and micro-climate, but an end product of hundreds, and sometimes thousands, of years of human history. 

Birch is the most common native tree found in the rainforest zone, with oak coming in second. In the far northwest, Caledonian Pinewoods merge with broadleaved woodlands to create a special type of temperate rainforest that’s found no where else in the country. 

While woodland with a mix of native trees tends to be best for supporting wildlife, as they have a greater variety of niches, hazel-dominated woods are actually some of the richest when it comes to rare lichens. These ancient stands of hazel were only recently recognised as a distinct woodland type, but if they’ve grown without coppicing, they can be very biodiverse. 

The trees of Scotland’s rainforest

Oak woodlands make up around a fifth of the total area of remaining rainforest. They’re so common because they’re a valuable tree for humans, and historically would have been encouraged to grow for timber and industries such as charcoal making. They’re vital habitats for thousands of different species of bryophytes, lichens, invertebrates, birds and mammals, some of which depend on the oaks completely for survival. However, because these woodlands were so heavily cut and managed in the past, many are in poor condition, and although wildlife is slowly returning, their full biodiversity may not be recovered for decades. 

Hazels don’t usually form big ‘trees’ but rather grow as multiple stems from a stump or stool, which could live for hundreds of years. Hazel trees are important for wildlife, including mosses and liverworts, several unusual species of fungi, including hazel gloves, and lichens such as the white script. With adequate sun, they can also produce large quantities of nuts each autumn, which feed birds and mammals.   

Birch is the most common tree in Scotland’s rainforest zone, and there are two species you’re likely to see: silver and downy. It’s common because birch trees are a pioneer species that produce huge quantities of light seeds, and can quickly spread into new areas. The young trees also seem to be less palatable for deer and other browsing animals, though they will eat them when their populations are high. 

Ash trees are easy to identify in winter because of their black, burnt-looking leaf buds. They’re an important tree for many lichens, and their late-opening leaves allow a lot of spring light to reach the forest floor. Sadly, these trees are under threat from ash dieback, a fungal infection that kills younger trees and terminally weakens older ones. Although often called mountain ash, our distinctive rowan trees, with their bright red berries, are actually from a different family and are not susceptible to ash dieback.

Scots pines are often found in the rainforest as individual trees. But in the north-west Beinn Eighe and Ben Shieldaig are two unique areas of Caledonian pinewood where Scots pines have adapted completely to growing within the rainforest zone. 

Willows love the wet soils of Scotland’s rainforest, and there are several species that you might see, the commonest of which is the goat willow. Goat willows are often an overlooked tree, but they’re important for the lichens they host on their bark, and for pollinators. 

Wych elms survive in remote areas of Scotland’s rainforest, particularly in Assynt. Dutch elm disease has wiped out most of our native elms, but these trees have survived because the beetles that spread the disease don’t like the cold and wet environment.