Researching the Burren Pine microrefugium so far...
Researching the Burren Pines and the Rockforest Microrefugium, County Clare
*captured from a recorded voice note then transcribed
Some questions I set out to answer
Before I read the study, I had a few questions of my own. Is it genuinely a "Burren pine," or is every other Pinus sylvestris simply a Scots pine? Where did the tree originate, and where's the oldest? And was Scots pine ever truly native to Ireland, or only brought in from Scottish stock in the 1700s?
Then, reading the paper raised sharper ones. How do you actually prove continuous presence, is the core just a long pipe down through datable layers of pollen? When they record a decline, is there a true gap big enough for Scottish replanting to fill, or does the pollen run unbroken? Can ancient pollen be genetically linked to the living trees at all? Are the Rockforest pines genetically distinct from Scottish stock, and can you even test that? And finally, what's the conservation goal, are they working to spread this native lineage back across Ireland?
My thoughts on the study
I initially began by reading the research paper by McGeever and Mitchell, published in 2016 in the Journal of Biogeography, titled "Re-defining the natural range of Scots pine (Pinus sylvestris): a newly discovered microrefugium in western Ireland." I found this very interesting. It essentially tested by coring into an area in the Rockforest, basically drilling out a large core. So if you can imagine something like a pipe that goes very far down into the ground, and they pull it all up intact, layer by layer. This was bogland, from what I understand, and they were able to record pollen deposits dating back many years, 2,000 years ago for example.
The main issue this research set out to overturn was the idea that all Scots pine had been extirpated in Ireland, meaning destroyed, lost, wiped out. It was then extensively replanted in Ireland during the 1700s from Scottish stock, after the species was thought lost here. The argument had been that Scots pine, Pinus sylvestris, is not native to Ireland. But this study proves it existed in the Rockforest in County Clare 2,000 years ago, with continuous evidence of the pollen all the way up to present day.
What was expected was that, in similar sites, the pine would not predate the 1700s, because it came from the Scottish stock. In the Rockforest, however, the continuous pollen evidence going back 2,000 years showed a continuous patch of Pinus sylvestris from that time. Although there is a decline at one point, it still predates the 1700s Scottish stock by a long, long time. So that was the evidence.
I had a couple of questions of my own. Could the DNA of the pollen found be matched with pollen on the current trees? The answer is essentially no. They could date the layers of the core, so the pollen is dated by how deep it sits in those dated sediments. Separately, Burren pine wood found in the bog has been radiocarbon dated to around the 9th century AD. But the ancient pollen itself can't be genetically linked to today's trees, because the DNA doesn't survive. The grains are essentially empty husks, so there's no way to directly match them to the living Rockforest pines.
The other question I had was whether these trees were distinctly different from the imported Scottish stock. There was a study done in 2023 on this. Basically, they weren't that much different, very similar to the Scottish stock that had come in. Now, that doesn't change anything. The whole point of the study was to prove there was Pinus sylvestris in the Rockforest for a long time, predating the 1700s, and that was proved.
Conservation
The other thing I wanted to know was what's being done to conserve it. There's a group called Burrenbeo, a conservation organisation that does many things, but one of their objectives is establishing standings of Pinus sylvestris, where they recommend, say, 100 Burren pine planted alongside other native trees. This allows for a seed bank at each standing. Tests were done, and the Rockforest Pinus sylvestris aren't at risk of inbreeding. So if they establish different standings around the country, the main goal seems to be to establish this tree around Ireland with no fear of inbreeding.
Hare's Corner seems to be a nursery and organisation as well, distributing seedlings, with a waiting list every year. I've missed the cut off for this year, but it starts again in early 2027, and I'd be looking to get my hands on a few Burren pines, to see if I can get them distributed in Carlow, or even just have some myself to do tests on.
References
McGeever,A.H. and Mitchell,F.J.G. (2016) Re-defining the natual range of Scots Pine (Pinus sytvestris L.):a newly discovered microrefugium in western Ireland. Journal of Biogeography,43,oages 2199 to 2208
Further reading
the 2023 molecular study of Pinus sylvestris in Ireland (BMC Ecology and Evolution), and the Burren Pine Project, Burrenbeo Trust, at burrenbeo.com/pine