, 20 November 2013

Author Tony Whitbread

Chief Executive

Sussex Wildlife Trust’s biggest woodland nature reserve is “The Mens” a fascinating ancient forest in West Sussex.  The name comes from the Old English “Gemenes”, meaning community woodland (German speakers might recognise links with “gemeinschaft” which means community) and, many centuries ago it was used by the local community for grazing and fuel wood.  For a long time now, however, it has been left unmanaged.

The Mens / Nigel Symington The Mens / Nigel Symington

When the Sussex Wildlife Trust purchased it in 1974 we took the brave decision to leave it entirely to nature. “Brave” because at that time the decision divided the Sussex Wildlife Trust  - some saw a dilapidated, untidy place that needed to be cleared up and replanted.  Fortunately, however, a non-intervention policy was established so we now have a rare example of “old growth” woodland, designated as of international importance.

This has given us an excellent opportunity to follow natural processes at work.  So, what have we learned about woodland processes and how might this help us in the current discussion on wild land?

The 1987 storm was perhaps one of the most informative events to hit woodland ecology for a generation.  People often thought of woods as stable, undisturbed places that predictably developed to form a dominant woodland type – the so-called climatic climax.  George Peterken (one of Britain’s leading woodland ecologists), however, had been explaining the vital role of natural disturbance in woodlands.  Forest ecology was not predictable, could be very variable and therefore very diverse.  Storms are examples of unpredictable, formative events that drive woodland ecology and benefit biodiversity.  Storms are good for woods and for the last 25 years I have been trying to put over this as the antidote to the “devastating damage of the 1987 storm” stories that we still sometimes hear.

Looking at The Mens you can get a rough idea of what might happen in absence of disturbance (or at least if disturbance is very light).  The wood was heading towards dominance by beech with an under-story of holly – two heavy shade-casting and shade resilient species.  Other species were gradually reducing.  Oak, hazel, hawthorn, much of the ground flora and woodland lichens were disappearing or becoming patchy.  Other species were doing well - such as fungi, fly species and hole-nesting birds.  The wood was becoming poorer in some respects but unusual species were doing well.

Oak is a good example.  Often assumed to be a woodland tree it does not, however, regenerate in dense woodland.  This was born out in The Mens – age class studies show that there were few very old trees, quite a lot of medium-aged trees but almost no young trees.  This is the classic sign of a dying population – there are no young trees to replace the old ones as they eventually die.

The storm, I thought, provided the answer.  Major gaps blown in the canopy every few centuries would provide regeneration opportunities for all the light demanding species that make up most of our flora.  Sure enough, in the 25 years that followed there was a huge pulse of regeneration in all the canopy gaps that were blown in the wood.  Broken trees sprouted, shrubs grew, ground flora colonised and we saw a few more birds inside woods that usually stay on the edges.

But the storm was not enough!

Oak has not regenerated in the wood and the canopy gaps are quickly returning to dense beech woodland.  Storms are indeed vital to create diversity and provide habitat for an array of species but alone they cannot explain the presence of species that we know have been present throughout history.

The storm, however, is just one case of natural disturbance.  By recognising the value of storms, it also opens our minds to recognising the function of a great range of other forms of natural processes.  Alongside storms is erosion and accretion by rivers and lakes, tree fall on steep slopes, gaps formed when fungi or insects damage swathes of trees and the disturbance caused by wild grazing animals as they move through the forest.  The behaviour of grazing animals would also be affected by the presence of predators which in turn would have affected the habitats they grazed or browsed on.

Even if we leave areas as non-intervention, as we have done in The Mens, we cannot simply assume that we have created wild land.  In effect we are making decisions by default by leaving areas alone – we have restricted nature (any non-intervention area is too small), we have excluded large grazing animals (they are extinct, not present or not allowed to behave naturally), we have excluded predators, we react against natural disturbance (by clearing up storm damage or preventing erosion) – and so on.  So non-intervention is a positive management decision which creates a human artefact as much as any other management decision.

So why do we keep The Mens as a non-intervention area? 

In spite of the fact that many natural processes are restricted in The Mens, any model for “the wild” would probably have included large areas of old growth forest where natural disturbance was indeed quite light.  So The Mens represents a type of habitat that would have been common in the wildwood but which is now extremely rare.  Although the site may be poor in many woodland species, it is rich in species that are restricted to old growth situations.  Also, The Mens exists in a landscape context.  Open habitat in areas around The Mens provide complementary habitat for many species that exist within the wood, so we do not need to create extra canopy gaps to maintain the biodiversity in the overall area.

The Mens is perhaps one of the best examples we have of what a “near” natural wood might be like.  It is a fascinating area to study.  But most of all – just go there!  It’s a magic place.

Leave a comment


  • Sally:

    Surely inviting lots of people to go there will disturb the aspect of non-intervention. Many people and dogs etc will surely deter some species which would otherwise populate the area? Not having been there or seen the woods, however, I can only guess but would like to hear your response. An interesting article and it sounds like a lovely place.

    23 Nov 2013 09:44:01

  • Andrew Holloway:

    This is a facinating report. It also perfectly describes the ancient woodland on and around Penland Farm, Haywards Heath, which has been unmanaged for a similar length of time. This rich habitat is now under threat from a proposed housing development which will remove nearly all of the fields that provide the open habitat described above. It is clear that if this development goes ahead it will sound the death knell for the ancient woodland. This area is also ‘magical’ and much appreciated by the local residents.

    23 Nov 2013 12:01:00

  • Andrew Rumbol:

    Very interesting article, thank you! Of course oak wasn’t a common climax community member in “traditional” English woodland though (compared to elm, beech, ash)… oak was actually quite rare, but planted/promoted extensively in crown hunting land – “forêt” – after the Norman conquest, for it’s relatively fast-growing and exceptionally hard/straight timber.

    Of course man has been shaping the face of our woodland for thousands of years, without our influence coppicing etc, gaps would close up and ground flora like oxlips would be lost. Man is part of the ecosystem now, I don’t think the problem is just the “unnatural” fragmented state of our woods, but that the climax communities of today have evolved under man’s influence (and what we think of wild healthy woodland is very different to the old woodland that once dominated our landscape). Also coppicing etc does provide a small revenue incentive to landowners!!

    That said this “experiment” is really interesting, I’ll definitely have to visit to see what a modern “wild wood” is like! Are the gaps created by the storm not maintained by deer eating young trees and saplings, or has the canopy fully regenerated now?

    23 Nov 2013 12:33:00

  • A very valid point Sally, and one we have to think about in nature reserves generally, not just in non-intervention zones. How do we encourage people to experience nature without them damaging the very thing they’ve come to experience? In practice many of our nature reserves are not overly visited and are reasonably robust to a moderate level of access so can probably take quite a lot more responsible access by people. I think this is the case for The Mens.

    However, an interesting thought by way of an example…. We are trying to plot the course of natural processes in The Mens, at least with minimal levels of human intervention. When people visit the site they will use the tracks that are there. As they are easy to use, deer will then use, and so graze alongside these same tracks. So deer will be influencing vegetation in a way first stimulated by human access. Hence human access will have determined the course of a natural process! An interesting quandary, and I like quandaries, but it is not one that I am too worried about. The range of variation is probably still relatively natural even though there are influences that we are not going to be able to avoid.

    Tony Whitbread

    25 Nov 2013 10:28:53