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 English 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 Scotland and Wales possess conditions for temperate rainforest, and this is increasingly recognised in both nations; less well known is that England also has large areas where temperate rainforest can grow, and almost certainly has existed within the last 10,000 years, although only tiny fragments remain today.
Major temperate rainforest zones in England are in the Westcountry (around Dartmoor, Exmoor and Bodmin Moor), the Lake District, the Forest of Bowland, the Yorkshire Dales, and the Pennines. In fact, England’s lost rainforests likely extended far 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 England.
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 England’s temperate rainforests as useless, good only for fuel or charcoal. This led to the destruction of many of England’s 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 England’s lost rainforests.