#26 Royal Fern by Alastair Fitter
Meet Professor Alastair Fitter, plant ecologist!
Alastair Fitter is a plant ecologist with interests in soil ecology, especially plant roots and mycorrhizas, and in plant and microbial behaviour in response to climate change. He published his first scientific paper nearly 50 years ago and has also written and collaborated on several popular natural history books and guides. He is Emeritus Professor of Ecology at the University of York. Alastair can be contacted via email at alastairfitter@btinternet.com.
Royal fern at Askham Bog, with the mound from which it grows visible.
Alastair has chosen the Royal Fern Osmunda regalis. Royal Fern is the largest fern in the British flora: although typically up to 1m tall, in exceptional old plants the fronds can be nearly 3m long! It is the only British member of its Family – indeed, of its Order, which is an ancient fern group whose origins date back 300 million years to the end of the Carboniferous era. It is the nearest thing we have to a tree fern, eventually forming a huge mound from which the fronds grow up each spring. Royal fern and its relatives have quite a different way of producing spores compared to other ferns - the leaflets at the end of some of the fronds get converted into sporangia (spore sacs), whereas in most ferns the sporangia are underneath the leaflets. You can find out more about the Royal Fern on the NBN atlas.
Royal Fern is a plant of western Britain and is a rare plant in Yorkshire, which hosts less than 1% of its British distribution. It has been known at Askham Bog, outside York, since the 19th century, when plants were regularly dug up and sold: several York gardens still boast plants that originally came from the bog! This trade was widespread: Slater’s Flora of Ripon (1884: Trans. Y.N.U. pp. 183-184) contains an extraordinary tirade against the collectors who are described as “that debased product of civilisation, that vile sort of poacher, the idle rascal who too lazy to work honestly . . . gains a sort of living by purloining roots of ferns by the hundred from every gentleman’s woods within his reach”. The terms of debate in the conservation world have improved in recent times!
Royal Fern is a very long-lived plant and at Askham Bog some of the plants are huge, reaching over 3 m in height. When Alastair first came to York, nearly 50 years ago, there were about 20 huge, old plants there and no young ones. It seemed the population was slowly dying out and indeed some of those original plants have since died.
“When I came to York in 1972 I quickly became involved in the conservation of Askham Bog, the nature reserve that led to the foundation of the Yorkshire Wildlife Trust in 1946. Although far from the rarest plants on site, the Royal Ferns are certainly the most spectacular and the fact that they seemed not to be regenerating made them special and in need of special attention. There are not many plants in Britain that cause people to stop, stare and gasp when they meet them: the giants of Askham Bog do just that.”
Young fronds of a Royal Fern emerging, with a mound visible in the background.
When Alastair and his colleagues discovered how important mediaeval peat cutting had been in the history of Askham Bog, they wondered whether the ferns needed bare peat to regenerate, which would explain the lack of young plants. Peat cutting began perhaps as early as the Roman period and continued probably until the early 18th century. Peat was cut for fuel by villagers of local communities including Dringhouses and Acomb and it changed the topography of the Bog: the removal of the top layers of the mound of acid peat brought the peat surface back down to the local water table and so restored fen habitats. But when cutting ceased, the lack of bare peat and the shade cast by the trees that then grew over the whole site may have prevented the ferns from regenerating. To test the idea that regeneration of Royal Ferns might require bare, exposed peat, the Yorkshire Wildlife Trust (which owns the site) created some new small, experimental peat cuttings. For years, nothing seemed to be growing in them, but recently it was discovered that many of them hold young Royal Fern plants, suggesting that the hypothesis was right!
What this experiment has shown is how slowly the plants grow and how easily overlooked the young plants are. It suggests that the big plants present on the site are really old. As peat cutting had certainly stopped at Askham by the 18th century, the old plants probably germinated when cutting was active, and so may well be many hundreds of years old – possibly the oldest living things in York. When they are at their finest in June, with the young fronds standing erect, they are quite awe-inspiring.
Monitoring
A young Royal Fern plant.
Members of the Yorkshire Fern Group have been mapping the baby ferns at Askham Bog over the last few years. In addition to 18 surviving old plants, they have discovered no less than 67 new ones, all of which must be less than 60 years old – the oldest of the ‘babies’ was found on the banks of a pond that was dug out in 1959 – and are mostly under 40. Those young plants mean that the future of Royal Fern in its Yorkshire stronghold seems assured.
Further information and acknowledgements
NEYEDC would like to thank Alastair for his time and expertise in helping to create this blog. If you’d be interested in contributing a piece for the series, contact Lucy at lucy.baldwin@neyedc.co.uk. To find out more about biological recording, see the Naturalists page on our website.