Sweet Chestnut Bark

This Spring and Summer we have been experimenting with some of the uses of the bark from Sweet Chestnut Trees and wish to share some of our findings.

The pictures are pretty informative and there is a separate gallery of all the pictures related to this.

Logs peel better when freshly felled and smaller diameter poles seem to peel later into the year than those of a larger diameter.
Logs peel best when there is a good sap flow so from spring into mid/late summer. In late August I could still easily peel coppice stems 2″-3″ in diameter while those any larger just didn’t work. In early August I could still peel coppice stems 6″ in diameter. [Could the amount of rainfall be a factor?]

To make things easier it is good to have some sort of break to hold your freshly felled pole while you work on it. I use my cleaving break as it gives a lot of different possible ways to hold things. There’s lots of ways to make breaks… use what you find works and that you feel comfortable with.
The smaller the diameter the pole the thinner the bark will be, so the first stage of the process is to get the bark to the thickness you need. For most uses about 1mm [1/16″] is good. With thinner poles, 2″-3″ or less in diameter this can be done by just scraping the bark with the back of a knife so that just the outer brown layer of bark comes off, leaving a pole that is green all over. This thin layer can be seen hanging down in the next picture while a thicker layer is being peeled, but the technique being used is the one for larger diameter poles which I describe in the next paragraph.
For larger poles 3″ and above I find that if I peel all the bark it is a bit thick and chunky for my current needs so I thin it down before peeling. I use a bill hook for this as I find it suits me better but you could use a draw-knife or even an ordinary knife.

What you are trying to do is to shave off a thin layer of the outer bark, without making the remaining bark too thin or, worst of all, going all the way down to the cambium.

If you go down too far you end up with a hole in the final sheet of peeled bark (like this) which gives you shorter usable lengths of bark.
When you have thinned the bark down over the whole pole you will end up with a white surface. Now what you are going to do is to remove all the remaining bark, down to the cambial layer,  in one piece.
Holding the pole in the break slice around one end of the pole, down to the cambium, to give a straight edge to work from.  Remove and discard that small length of bark.
Then slice down the whole length of the pole, parallel to its length and just down to the cambial layer.

This will give a straight edge to the removed bark.
Next lift both edges of the bark, either side of the scored line, starting at one end. Slowly lift the bark and it will begin to separate from the wood at the cambial layer. If the bark is peeling well it will easily separate and you will be able to slide your finger(s) underneath.
Slide your finger up and down along one edge, under the bark, and gradually more and more will lift. It’s a very sensuous feeling with the sap lubricating all surfaces as you go, a bit like skinning a rabbit! Do this on both edges. Take care not to make splits in the bark.
At some stage there will be enough length of bark peeled for you to fold it downwards at the end of the log so that the end of the pole is free of bark.
Keep pulling the peeled bark downwards while continuing to slide your fingers up and down under the edge that is being peeled. If you come up against a knot (or a peg where a twig has been removed) carefully work your way around it. It’s at these points where the peeled bark is most likely to split, but if you’re careful you should be able to work around it and just end up with a small hole.
Eventually the whole sheet of bark will come off in one piece.
At this stage the sheet of  bark can either be dried for later use or cut into strips, of the width that you need, straight away. If you are going to dry the bark for later roll it up along its length as this will help to keep it flat. This will make it easier to handle at a future date.
You can manually cut the bark into strips of the width that you need but it can be pretty hard to keep them even. Often people do this by sticking a sharp knife into a table or plank (a set distance from the edge) and then pulling the bark past this blade. This works fairly well but is hard to control and is much easier if the bark sheet is flat.
You only get really flat sheets of bark from really straight, knot and branch free, poles. Most peeled bark is a bit wriggly.
It’s quite an easy thing to do to make your own tool to split strips off of the width that you wish.
This tool is made from a few scraps of wood, a blade (like a single edged razor or a Stanley knife blade) and a couple of screws.
Place the edge of the sheet of bark into the slot in the tool and then pull the tool along the edge of the sheet, making sure that the bark stays in contact with the bottom of the slot in the tool. If the bark does not touch the bottom of the groove in the tool the strip created will not be of an even width.
[I’ll give more details of how to make this tool at a later date but is should be pretty obvious from these pictures and those in the gallery .
I did have a bit of a woodsman eureka moment when I was peeling bark early in august… After I had completely peeled a pole, as described above, I was scratching at the beautifully smooth sappy surface and I noticed that a thin sliver of ‘wood’ had come up. I pulled it and it ran down the whole length of the pole giving a material just a few cells thick. I experimented and found that it was quite easy to remove strips of this material about 1″ wide. It seems that I can only get it to work straight after the pole has been peeled, leave it for more than an hour or two and it just won’t do it.
Carefully lift up  a thin layer of  tissue, from the peeled log, about an inch wide. If it is in narrow sections [ie 1/4″ wide]  lift them up one at a time adjusting them until they all join into this 1″ wide strip. Once they are joined together place the edge of your knife underneath and your thumb on top of the end of this strip. Lift slowly unlil you have about an 1nch or so seperated from the pole. This is quite a crucial stage as it is now that the strip seems to consolidate itself for width and thickness .
Once you’ve reached this stage it’s pretty straightforward… Place a finger of your other hand on top of the junction of where the peeled strip meets the pole , this is to control the strip and to stop it splitting into separate sections, and continue to pull upwards at right angles to the pole. Continue along the length of the pole… it’s mare a matter of feel rather than a logical technique. When you meet little stipules or imperfections slow down and just work your way around them. If the strip separates into two or three pieces [as at the beginning] just manipulate them until they join together. The peeled product is very sticky with sap and I give it a bit of a wash so that all the pieces don’t stick together when you coil it up.

I haven’t experimented extensively with this material but it is a bit sinew like and very strong, for it’s thickness, when wet and good for fine binding. I did ply some by twisting and it made a material a bit like the sea-grass that is used for seating stools & chairs.
In general I would suggest that you let all these bark products dry out a bit before coiling for storage otherwise they go moldy. If you coil too many lengths tightly together, even when slightly damp they also get mold. So a bit of air circulation seems to be the order of the day.
I have heard it rumored that boiling your bark strips with the outer bark that you scraped of at the beginning acts as a preservative as it is full of tannin. I don’t know if this is true but it does dye things a nice colour.
When dry the stripped bark is brittle but a soak in cold or warm water soon makes it flexible enough to use for a few hours. I’ve used the bark for seating stools and basketry and although it looks very uniform in strips when woven there are a vast array of different earth colours. which make the finished articles truly beautiful.

Experiment yourselves next spring and please give me feedback, particularly on uses for this under-bark.
As a postscript I did meet some folks at Bentley Wood Fair who were using a pasta machine to split their bark into very narrow strips. It seemed to work a treat and I’ll experiment myself next spring. They were such nice folk I’m pretty sure they won’t mind me sharing their technique.

Peeling Sweet Chestnut Bark Gallery

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