Temperate Rainforest

Our discovery

A few days ago, as we were walking through Loch Lomond and The Trossachs National Park, we discovered something quite amazing: there is rainforest in Scotland. Who knew? Well, certainly not us! So I figured it was worth doing a little home education piece on it to raise awareness, as there isn’t a lot left and what is left needs to be protected because it’s a totally unique ecosystem.

The map on the right shows where rainforest is located along the West highland Way. This particular section is in Loch Lomond Woods SAC (Special Area of Conservation).

https://lostrainforestsofbritain.org/2021/03/16/mapping-the-lost-rainforests-of-england/
https://www.sciencedirect.com/science/article/abs/pii/S1470160X16303016 (Ellis, 2016 Oceanic and temperate rainforest climates and their epiphyte indicators in Britain)

How can we have rainforest in the UK?

What usually comes to mind when you hear the word ‘rainforest’ is the hot and tropical kind. Scotland is neither of those things so how come it has rainforest? The hot kind is called tropical rainforest but temperate rainforest occurs in temperate zones (sometimes called mid-latitudes as they exist roughly between 30 and 60 degrees north and south latitude) that receive heavy rainfall due to the influence of the sea (oceanic climate). They need to be wet and humid all year round, with a mild temperature that doesn’t change much throughout the year. In the UK they are found in small pockets on the west coast of Scotland, Wales (Snowdonia & the Elenydd), and England (the Lake District, Forest of Bowland, Yorkshire Dales, Pennines and Westcountry). The west coast of the UK is generally wetter because of the influence of the Atlantic Ocean & the dominant prevailing westerly winds. You can read more about the climate of the British Isles here: http://thebritishgeographer.weebly.com/the-climate-of-the-british-isles.html  You can see how the cooler temperatures and the higher precipitation fit in with the map of remaining temperate rainforests in the UK.

What makes a forest a temperate rainforest?

Basically, temperate rainforests are very damp woodlands with heavy rainfall. Because they are so damp, the common polypody fern can grow as an epiphyte. An epiphyte is a plant that grows on another plant. In temperate rainforests the polypody ferns grow on trees. A temperate rainforest will have an abundance of mosses, lichens and polypody ferns decorating the branches and trunks of trees, and are far more biologically diverse than your average woodland.

Rainforest zone of the west coast of Scotland (https://www.woodlandtrust.org.uk/media/4792/state-of-scotlands-rainforest.pdf)

Why do only small amounts remain?

Temperate rainforests of the UK date back to the last ice age (10,000 years ago) and would have formed an ancient forest belt down the Atlantic coast. It’s possible that as much as 50% of all temperate rainforest has been destroyed and now only remains in small fragmented pockets. Many of the UK’s rainforests were lost long ago to Bronze Age farmers and Medieval tin miners, and some have been lost more recently by misguided forest policies, e.g. felling ancient shrunken oaks in favour of fast growing sitka spruce plantations. In many places they have been overgrazed by sheep, which prevents regrowth, or choked by rhododendrons.

In Scotland, where they are also known as Celtic rainforests or Atlantic woodland, it’s estimated that only around 30, 325 ha of rainforest survives.

Identifying temperate rainforest

Temperate rainforests (Atlantic woodlands) are internationally important for their lichens and bryophytes. Bryophytes were amongst the first plants to colonise land and are simple plants that include mosses and liverworts. Atlantic woodlands rival the cloud forests of the tropics for their bryophyte diversity. Lichens are a symbiotic association between fungus and algae and/or cyanobacteria. The UK has an obligation to conserve the many rare species of lichens, including tree lungwort.

Some things to look out for to identify temperate rainforest:

  • Woodland floor and boulders are carpeted with bryophytes
  • Lichens on tree trunks
  • Indicator species such as Tree lungwort (Lobaria pulmonaria), ‘Stinky’ Sticta species, String-of-sausages (Usnea articulata) and Witches’ whiskers (Usnea florida) are present

https://www.johnmuirtrust.org/whats-new/news/108-new-coalition-launched-for-fragile-rainforest
Eve, 1st May 2022, walking down the stretch from Rowardennan to Balmaha. Are we in old temperate rainforest here?

Unfortunately we didn’t know about the temperate rainforest as we were possibly walking through it, which means we didn’t stop to investigate. The photo on the left certainly has bryophytes on the boulder (old tree trunk?) and tree trunk just to the left of Eve’s head. There are possibly some lichens on the tree trunk too, although it’s difficult to say from the photo. You can also see plenty of ferns, but again it’s difficult to see if any are growing as epiphytes. We know we were close to some rainforest and it’s exciting to think we may have walked through it, and that it’s thousands of years old!

If you would like to know more about temperate rainforests, the mission to save them, and the mission to map them, please visit the links below. These also include the links to websites that all the information here came from.