Garden School:


Garden School:
Teaching this week: Assessing a new garden, and when to say "No" !

Tuesday, 22 January 2019

Hazels: what to do with an overgrown coppice

Last week, I received a question: what to do with an enormously overgrown old Hazel coppice.

Now, before we get on to what to do with it, a quick reminder about coppicing: time out of mind, it was a way of managing woodlands, in order to produce useable materials for fencing, furniture, firewood and fodder - all sorts of things. It involves repeatedly chopping a young tree down to - usually - ankle height, which prompts it to send up new shoots from the chopped base.

These new shoots will all be pretty much the same size as each other: so instead of one big central trunk with a lot of smaller, wiggly side branches, you get a whole bunch of same-sized shoots, and because they are crowded together, they fight for the light, which means they grow up vertically, nice and straight.

When they are big enough, they are all cut off at the same time, and the cycle repeats. 

This is usually seen on trees such as Hazel, Willow and Sweet Chestnut, but is also used for Oak, Lime, Alder: depending on what the trees were to be used for.

Alas, these days we don't need much coppiced wood: we don't burn faggots (bundles) of thin wood, we buy in seasoned and chopped hardwood. We don't make our own walking sticks, or fences, or hurdles: we don't make our own charcoal, either! So most of the coppiced woodlands have been left to return to the wild, over the last  50 years or more.

You can see them everywhere: next time you are out for a walk, or visiting a stately home, look at any areas of woodland that you pass, and check out the trunks: are they all one-trunk-per-tree? Or do some of the trees appear to have multiple stems, all sprouting from the ground? These are the remains of old coppicing.

In fact, the very name "copse" means an area of coppiced woodland.

You are probably also familiar with pollarded street trees: this is just coppicing at a higher point above the ground.

So, this question: John said that he has been asked to renovate a couple of very old coppiced Hazels, which were choked with holly at the base, and are very congested.

Here's a picture of one of them, half-way though the holly clearance:


"Good job!"

This is definitely the first thing to do: clear away everything other than Hazel, including ivy, brambles, and anything else growing around the base.

John asked what the best plan would be, to renovate these trees.

There are several reasons for wanting to renovate old coppices: they are part of our agricultural and social heritage, for a start.

Also, coppicing keeps the tree in a "juvenile" state, so that it does not ever grow old and die, the way that single-trunk, "normal" trees do. Honestly, that's true! There are coppiced trees which are hundreds of years old. So by allowing a coppiced tree to revert into being a "proper" tree, we are actually killing it.

And, of course, a renovated tree just looks better! Overgrown coppices such as John's ones, above, are unsightly, they are full of weedy choking growth, there is a risk of dead limbs dropping, and there will be lots of dead wood in the centre, which will be hosting pests and diseases: far better to put in a bit of work to restore the tree.

I wrote about the general principles of coppicing some time ago, when I had to restore a much smaller Hazel.  That one was more of a decorative tree than a crop tree, and the owners didn't want it coppiced, they just wanted to be able to get up and down their steps in safety.

John's trees are more historical: he thinks that they may be at least 50 years old, they may well be much, much older. They are also what you might call "public property" as they are on land which is accessed by the public, so it's important that they are both safe, and handsome to look at.

So, what would I advise?

The obvious suggestion is that it is high time they were coppiced again! Get out the bowsaw, and cut every single stem down, as low as you can.  Pull out any seedlings of other trees which you may well find lurking in the centre, and clear out any ivy etc that was hidden by the larger growth.

In seven years' time, do it again.

Drastic, but simple, and historically correct.

However, this leaves a big hole in the horizon, in which case you can do what I call a cosmetic coppice: this is where you cut out the largest, ie oldest, of the re-grown stems, leaving a thinned-out selection to give some vertical cover, while the new shoots grow.

If the tree is normally only seen from one side, you can choose to cut down one half of it - either the front, or the back, as it were.

If it can be viewed all round, then you can choose to take the time to thin it out by removing just the largest ones: but this can be time consuming, and tricky to do, as you have to get your tools in amongst the younger stems, without damaging them. It's perfectly possible, it just takes longer.

Every year thereafter, you would need to cut out a few of the oldest stems, and after a few years, you will find that you have a nice mix of thinner, younger stems.

If you are wondering why I say to cut out the older wood: well, if you cut out the youngest, thinnest, stems, then you are not renovating the tree, you are merely sending it back to being a tree instead of a coppice, which will eventually lead to its death.

And yes, it is perfectly possible to turn a coppiced tree back into a "normal" tree, by cutting out all but one or two of the stems - leaving the biggest ones - and allowing just those ones to grow. This means an annual prune of the base, to remove all competing new shoots, and you will always have a strange lumpy base to the tree: but yes, it will eventually look like a "proper" tree again.  This is kind-of what I had to do for the Client mentioned above, when I restored their Hazel

So, as John has two of these monsters to deal with, he could choose to properly coppice one of them now, and then in about three years' time, coppice the other one. Hazel, in case you are wondering, is normally coppiced on a 7-year cycle as it is a fast grower, so that's why I'd suggest about three years between working on the two of them: one will be half-grown before the other is chopped.
 
As an aside, Oak used to be coppiced on a 50-year cycle... we live our lives so fast these days that it's hard to comprehend an investment system that would not pay out for 50 years or more, isn't it!

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