Few people realise that Britain harbours fragments of a globally rare habitat: temperate rainforest.
Everyone’s heard of tropical rainforests. But we also have rainforests in Europe! Temperate rainforests occur in mid-latitude, temperate zones, in places which receive heavy rainfall due to an ‘oceanic’ climate.
Put more simply: temperate rainforests are very damp woodlands – so damp that plants grow on other plants. These plants are known as ‘epiphytes’. If you want to recognise temperate rainforest in Britain, the key indicator is an abundance of mosses, lichens and polypody ferns festooning the branches and trunks of trees.
The hallmarks of British temperate rainforest: polypody ferns, mosses and lichens carpet branches on trees growing along the O Brook, Dartmoor.
The temperate rainforest bioclimatic zone in Britain has been mapped by Christopher Ellis (2016) (see below). Large swathes of England, Scotland and Wales possess conditions for temperate rainforest. Although only tiny fragments remain today, the west coast of Britain would have supported far more rainforests in the period between the last Ice Age and the Bronze Age; some of our rainforests were cut down as recently as the 20th century.
Major temperate rainforest zones in Britain are on the west coast of Scotland; Snowdonia and the Elenydd in Wales; and in England, the Lake District, Forest of Bowland, Yorkshire Dales, Pennines, and Westcountry. Our lost rainforests may also extend beyond the main zones shown in Ellis’ map, into damp ravines and steep-sided gorges across the western seaboard of the country, where the moist microclimates can support epiphytes. One of the first things I’m trying to do is crowdsource a more detailed map of remaining fragments of temperate rainforest across Britain.
In some ways, British ‘temperate rainforest’ is a recent re-discovery – or re-branding – of a habitat previously known by other names. It used to be called ‘Atlantic oakwood’, being predominantly (but not solely) oak woodlands found along the Atlantic seaboard. In earlier decades, it was often simply referred to as ‘scrub oak’. This was partly descriptive – many upland oak woods have shrunken, shrublike forms – but also pejorative. Unlike the sturdy lowland oak, whose mighty trunks provided timber for England’s navy, many saw the twisted and stunted oaks of Britain’s temperate rainforests as useless, good only for fuel or charcoal. This led to the destruction of many of our rainforests.
Where are temperate rainforests found around the world?
The map below is taken from Mackey et al. (2017), who adapted it from D.A. DellaSala, Temperate and Boreal Rainforests of the World: Ecology and Conservation (2011). As you can see, it’s a globally rare habitat, and the UK’s temperate rainforest is of international importance. So let’s bring back Britain’s lost rainforests.