Coppicing the Hedge

A huge tree casting a lot of shade

A huge tree casting a lot of shade – and it’s supposed to be a hedge!

Over the past three weekends, we have been working on a very overgrown hedge between Alvecote Wood and Betty’s Wood. In particular we have been working on several very large holly trees, about 40 feet/15 metres high. These had been cut about 30 years ago, but the hedge has not been maintained since then. In consequence these trees have grown huge, and were cutting out a lot of light on the southern boundary of the wood. Behind the trees was some poor sycamore scrub and some bramble. We tried to get hazel established here, but it was just too dark. Nothing would grow.

So this year we decided to coppice back this holly hedge, removing three enormous holly trees (some with up to eight stems each), a couple of sycamore, hazel and hawthorn to open this area up and let in light.

We have also cleared the bramble, and plan to plant this area up with some hazel, birch and cherry, and also encourage oak seedlings to grow between these trees.

The photos tell the story: before, during and after.

There are also two videos showing how Stephen felled a particularly awkward twin-stem holly.

Felling the large holly

Felling the large holly

After, hedge is coppiced and a lot of light coming in

After, hedge is coppiced and a lot of light coming in

Shows the light coming into the area

Shows the light coming into the area

Apologies that the first clip of this video is out of focus.

Coppicing

This year's coppice

This year’s coppice showing the cut stems and large amount of light coming into the area

Coppicing is a traditional form of woodland management.  It seems counter-intuitive to cut down trees when you are trying to preserve ancient woodland but this is exactly what is needed.

First of all, a lot of species do not live very long unless they are coppiced.  By coppicing I mean cutting the tree down to allow it to sprout again from the base.  Hazel, in particular, thrives upon coppicing, living many times longer if it is repeatedly cut and allowed to regrow than if it is just allowed to grow and decay.  Other coppice species include ash, sweet chestnut, sycamore (not in our ancient woodland!), oak, willow, birch and alder.  Shrubs such as hawthorn, crab apple, holly and elder also coppice well.  In fact most trees will coppice provided they are not too old when cut, and provided the stems are protected from browsing while they are regrowing.

Our great ancient oak trees are not suitable for coppicing, but a relatively large area of our woodland has young, scrubby trees growing fast and crowding out each other and the light.  It also has an un-managed hedge boundary between the main woods and Betty’s Wood that can be revived by coppicing.

We started coppicing in 2009-10, cutting an area of predominantly willow, hawthorn, oak and a bit of hazel.  Since then we have extended the coppice area.

The photos here show a sequence:  the top photo is what an area is like when it has first been cut.  It looks bleak and empty, but it is not.  The key thing is that we have let in a lot of light to the area and this will stimulate both regrowth and regeneration.  At this stage we can do some targeted planting if we want to improve the diversity of the area.

2 and 4 year coppice

Coppice from 2 (foreground) and 4 (background) years ago showing regrowth

The next photo shows coppice that was cut 2 years ago.  It is regrowing quite strongly.  You can see we have protected the stumps (called coppice stools) using a combination of stock netting and chicken wire to prevent browsing of the new shoots by deer and rabbits.  This is essential – browsing can easily kill a regenerating coppice stool.  You can also see that there is a lot more ground flora in this area. A lot of woodland plants rely on coppicing to thrive, coming up periodically in the cleared areas to benefit from the light.  As well as some bramble, we have a patch of violet in this area, and the bluebells are spreading into what was once a sterile piece of ground.  Finally, we get natural regeneration happening – willow and birch seedlings are thriving because they have access to light, and where they come up, we provide them with protection.

4 year coppice

Coppice cut 4 years ago showing strong re-growth

Above we have a piece of coppice that was cut four years ago.  The regrowth on the willow, in particular, is over 10 feet/3metres, and the poles are 3 to 5 cm diameter at the base.  The hawthorn and oak are regrowing more slowly and will be cut less frequently.  There are some young oak that we are leaving to grow up as specimen trees or “standards” in our “coppice-with-standards” system.  We have also done some planting to increase the amount of hazel and ash in this area.  The regrowth will result in us being able to cut it again at about 7 to 10 years, and thus have a sustainable source of wood for craft, habitat and firewood.

We do the work ourselves.  It is not always straightforward as you can see below with a sequence of photos from the past weekend.

Hooking up the winch

A difficult twin-stemmed holly needs winching down

This year we are, amongst other things, clearing a patch of holly.  This has been slowly invading the coppice area and the problem is that it cuts out the light, particularly in the spring, which holds back regeneration.  Holly springs back very quickly, usually from root suckers, so we are not destroying this patch of holly, just reviving it, and allowing the coppice to thrive too.  However coppice species often have multiple and quite inter-twined stems.  This particular holly was separated at the base, and had welded itself together higher up, which mean both stems had to be felled together.  The area was confined, and the holly got “hung-up” rather than falling straight down.  we had to set up a winch to roll the tree away from the branches that were holding it.

Setting up the winch

Setting up the winch

We were using another, larger tree as a winch point, and you can see in the foreground the log pile, a brash pile (leaves and smaller stems) and behind that a habitat pile.  About 1/3 to 1/2 the brash will be left as habitat piles for birds and mammals to nest in, and the rest will be chipped to provide a good, dry surface on our paths and they will eventually rot down.  The log pile will be used mainly for firewood but the straighter stems may be used for rustic furniture making and some green wood turning.  We select wood that has crevices and particularly wood that is already a little bit rotten for the habitat pile.  Very large logs usually come from fallen branches, and we use these as sitting logs around the woods, and they provide habitat as they gradually decay.

Felled holly tree

Felled holly tree

We finally managed to fell the large holly (about 40ft, 13 metres tall), and here it is on the ground.  The smaller stem is underneath slightly to the right and cannot be seen in this photo.

Felled holly

Felled holly showing just how much light is now coming in.

And here are the final results.  You can see just how much more light is being let in.  The ring of stumps around the large oak are all holly, and you can see just how much it was dominating the area.  We still have to cut the hazel in the hedge in the background, and then our coppice will be open to the sun and ready to regrow strongly.  There is a lovely standing dead tree in the background too, providing excellent habitat for wildlife.  We leave our standing deadwood as habitat, and have no plans to fell this old tree.

In future we will extend our coppice along Betty’s Wood boundary to refresh the boundary hedge.  We always leave joined-up canopies as a route for dormice (although we have no evidence that they are present despite a survey for them), and never fell old trees with holes and hollows that are good habitat for owls, bats and other creatures.  The younger trees, however, should respond very well and the whole woods should be rejuvenated.  The coppice only comprises about 1/5 of the woodland.  There are other areas and plenty of other habitats being managed in different ways.  We have some areas planted with young trees that will become coppice of the future in the ancient woodland and in Betty’s Wood which was planted in 2010-11.

Coppicing is part of the way in which we try to ensure that there is an excellent variety of habitats in our woods – we also have mature ancient trees, wood pasture, wildflower meadows, hedgerows, dead hedges, thickets, areas that will become continuous cover forestry, and wet woodland, as well as eleven ponds.  The wildlife has already responded and we hope to report more and more species making their homes in our woods in the future.

The right tree in the right place by the right method

planting trees

There seems to be a perpetual tension between trees and other habitats, and within the tree category between planting and natural regeneration, sometimes with very entrenched and strongly-held views, particularly now the Independent Forestry Panel has weighed in with its support for increasing tree cover in England.


So how do we decide what is the right tree and what is the right place?

First of all, we could let the trees decide. That is what natural regeneration is, right? Well, I’m not so sure that is always the case. Many trees are pioneer species that will rapidly colonise other habitats. Indeed, many of these habitats are only as they are because one way or another the growth of trees is controlled: by agriculture, grazing, burning, climate or some other activity. It is wonderful to watch a habitat being re-colonised. Across the canal from us is a former spoil heap that has recolonized within my lifetime with woodland, mainly birch, oak and willow. Within our own wood, there are areas recolonising naturally too.

But there are also areas, such as heathland, which are valuable and declining habitats in their own right. The growth of trees there would endanger the habitat, and in many places, even in areas such as the New Forest, these trees need to be controlled to preserve precious habitat.

So, if we don’t let the trees decide, should we plant instead? There is a lot going for planting. You get quick results. The woodland becomes economically viable in a short time. You can connect fragmented habitat quickly. There are lots of grants and incentives to plant. You can engage the community in planting very easily. Young trees grow rapidly and fix a lot of carbon.

The problem is that there are also arguments against planting. The trees are likely to be all the same age, and it will take a long time for a diverse woodland to emerge. You may introduce disease, alien species, or cultivars that don’t thrive locally. Planted trees need a lot of maintenance, at least in the first few years. Planted trees don’t often come with associated mycorrhiza that are needed for healthy growth. Planted woodland tends to be less ecologically rich than naturally regenerated woodland. Planting may suppress natural regrowth and skew the balance of species locally.

Even on ground where woodland is wanted, and appropriate, regeneration is slow, and doesn’t come with appropriate subsidies, and it can also be taken over by invasive non native trees such as sycamore, and threaten other local woodlands.

So how do we achieve the right tree in the right place and who decides? I am sure our own decisions have been flawed, but were made in good faith, and sometimes because of financial constraints and incentives.

We have done our best to stimulate natural regeneration that was lacking in our own woods by bramble clearance, protection of saplings, introduction of light and so on. It seems to be working in some places and not in others.

We have also planted some areas to provide more diverse understory. Why? If we don’t do this, the elder growing on site because it is too fertile due to years of animal grazing simply takes over and we have had to resort to planting with species already on site to suppress this and allow the woodland to regain the diversity it has lost. How do we know it has lost diversity? Mainly because of the ancient hedge around the edge, and the diversity still present in the areas where animals were excluded.

Was this right? I don’t know. Some of it used our own seedlings, some didn’t. All I can say was it was done with thought, knowledge of the microclimate and soil, and careful weighing up of pros and cons.

Then there is Betty’s Wood. Appropriate for trees? Well few would say no. It was on poorly productive wet farmland, and connects two pieces of ancient woodland fragmented for years but clearly connected in the past.

The ideal solution would be natural regeneration. Except that the ground has been seriously disturbed and over fertilised with chemicals to maximise yield. Natural regeneration would be anything but natural. But planting is unnatural too.

What we have done is some of each. We have planted the centre section, and left the edge, where there are already trees to provide seed, to regenerate. In practice this seems to be appropriate in that there aree hardly any natural saplings growing outside this regen area. The centre section we planted with wildflower meadow and then planted into it, mindful of the soil, microclimate and the species already growing in the area. We planted in natural curvy lines to allow access for maintenance in early years and left large meadows, thickets, clumps and other features. Planting density varied, so some was spread out and the rest closer, to provide maximum variety.

It is no ideal. Many would say right place, possibly right trees, but wrong method. But the long and short is we wouldn’t get the money for natural regeneration alone. Herein lies the problem. I think in our case, planting was the best method, although others will no doubt disagree. But in many places it isn’t. But if we are to persuade people to allow tree cover to expand on their land, if it is right to do so, then we need to offer finance for this, or all the new woodland will be planted. At least we were allowed to regenerate over 16 thousand square metres of land and still get the money provided we met the density target over the whole site.

I don’t know if we have achieved the right trees in the right place by the right method. But I do think there needs to be much more flexibility over how expanded tree cover is achieved and in particular the method by which it is achieved. There also needs to be a great deal of thought put into identifying appropriate land for trees, so that neither productive agricultural land, nor precious alternative habitats are harmed.

Much will depend on the system put in place to achieve this. However given the target-driven nature of governments, planting is likely to get the nod. That is likely to create a lot of woodland very quickly, it of what quality? Do we really want lots of even-aged plantations? Will these really be well managed to encourage emergence of diverse ages and habitats? Will they be put in the right place or just the cheapest place? I have no idea. I just hope that people do put a bit of thought into what they are doing, and why.