Understanding Small-leaved Lime trees.

Ancient woodlands are more than just interesting plants and animals. They are part of the story of our social history but, like a detective, you need to know what clues to look for.

About ten years ago I was part of a project studying autochthonous (locally native) tree populations in the area, part of which involved visiting many of our ancient woodlands. This then is a story about the largest ancient woodland in my area which grows on the steep sides of the Kilton Beck Valley (Beck is a local name for stream). It’s also about a single tree in that wood.

Kilton Beck Valley

The Kilton Beck valley woodland is a joy to explore –in theory there is a public footpath through it, but over time parts have been washed away or lost when the valley sides have slumped naturally leaving deep chasms of clayey mud and a tangle of fallen trees. To get up the valley is one huge adventure and you don’t see a soul all day; it’s just you, the trees and an occasional deer. I love it.

Kilton Beck Valley downstream small

In this woodland is a small population of one of the scarcer local tree species, small-leaved lime (Tilia cordata). Up here on the edge of the North York moors is almost the northern limit that you can find them (there are a few in Durham and the Tyne Valley). The trees very rarely, if ever, set viable seed now – our north eastern summers are usually too cold for fertilisation to occur.

Kilton beck valley upstream small

The first time I visited the woodland I was delighted to spot some of the lime trees of which there are only a few and those few are scattered about, and so not easy to find. At the time I think was more interested to discover what looked like narrow old roads (long since abandoned to hazel bushes) cut along the valley slopes and occasionally dropping down to the beck …a bit of pondering later and then it occurred to me that the roads would be needed to remove any cut timber. Just because nothing is harvested from the woods now and the place looks wild and abandoned doesn’t mean that was the case in the past.

It wasn’t till a later visit that I noticed something odd about the lime trees – a thought process that was triggered by the tree below which looked as though it had been coppiced (when most native trees are cut to the ground they can regrow from the cut stump – a sustainable way of harvesting wood).

Clarkson's coppice small

Earlier, at the top of the valley slopes, I had seen many sessile oak trees that had obviously been coppiced before and I knew oak trees were coppiced and then the tannins from the stripped bark were extracted and used in tanning cow hide.

And then, whilst wandering about, I noticed three small-leaved lime trees growing in a triangle roughly equidistant and about 5m apart. I looked around nearby and there were no other limes, just these three. You know when your imagination starts? – what if there was once a single tree in the centre of the hollow and it had been coppiced for so long that the cut bits in the middle had rotted away and all that was left were these three trees?

Clarkson's three lime trees plus red small

As I walked (scrambled and beck-jumped in reality) up the valley I spotted a few other clusters of small-leaved lime, a bit like a tree version of mushroom fairy rings. But it wasn’t until I was on the way back down the valley and almost back at my car that I noticed a very large semi-circle of limes. Out came the tape-measure and the semi-circle was ten metres in diameter. Ten metres…just how long would you have to coppice a tree for it to get ten metres across?

Whitecliff wood 10m limes plus red small

There is only so much you can find out from books; eventually you need an expert you can call. So I did. I asked Donald Pigott – a world authority on Limes – to visit, although to be fair I don’t think it was me doing the persuading, it was the lime trees – I just sent him pictures and a description.  Actually, I’m always amazed at how experts like him give up their time freely to help, and wonder if it happens in other professions.

Don & Martin corrected small

He looked at the limes, was impressed, took a core of wood from one of the trees to work out how old the trunk was (by counting the growth rings in the wood), had a great time and went home. He sent a report. There were 62 rings on the core and it didn’t quite get to the centre of the tree so he suggested an age for the tree trunk sampled of around 67 years – meaning that the whole wood was then probably last coppiced around 1938-ish (most probably because of, & during, the second world war). He wrote that “Each group [of small-leaved limes] is almost certainly derived from a single original tree by coppicing…” and that single tree grew between 400 and 500 years ago.

How amazing is that?

Just think, for the last 500 years that same tree has been growing in the same spot, has been cut down time and time again so that the wood can be used by someone, and has grown back again and again and again. As Donald Pigott said in his report “…limes seem to be virtually immortal.” In that time at least 16 generations of people have stood next to the same tree where I stood – well perhaps not the same bit of the tree and they did all chop it down, but definitely the same genetic individual – like an old friend who is always there.

Every piece of ancient woodland has a story like this, where the trees are living connections with people in our past. All we have to do is go to an ancient woodland and look.

Postscript

Near the small-leaved limes in the Kilton Beck Valley are the ruins of a small castle, Kilton Castle, apparently built in the Twelfth Century and starting to fall into disrepair by the fourteenth. Perhaps those small roads I noticed were in use to take the coppiced wood up to the castle. Lime trees were especially valued then because it was possible to make rope from the fibrous inner bit of their bark (called bast).

Kilton Castle small

If you are interested in ancient woodland then the book ‘Ancient Woodland’ by Oliver Rackham is a treasure trove of information.

‘Lime-trees and Basswoods: A Biological Monograph of the Genus Tilia’ by Donald Pigott was published in 2012.

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