Woodland Management for Biodiversity

Woodland Management for Biodiversity

A woodland acts as a reserve for the whole landscape, linking a network of habitats. Vast amounts of Cornwall’s landscape are arable and pastoral with woodlands often isolated. Over time our environment has lost species with limited mobility that have been unable to recolonise. Therefore, management should aim to sustain all species present and enhance the ability for indigenous species to thrive and regenerate. The flora of ancient woodland, particularly coppices tends to be richer than more recently planted woodland. However, a neglected woodland can decrease diversity after becoming compact, with one or few species of tree dominating the landscape. The trees can be of similar age and height, with a closed canopy and can subsequently become etiolated.

The management plan for our own woodland is not to sustain a timber supply, but for the sustainability of a species rich environment. (although excess timber, post deadwood retention will be of benefit for crafts and shelter building),

These techniques include:

  • Woodland thinning.
  • Coppicing of some trees.
  • Planting of native tree and shrub species.
  • Veteranisation techniques.
  • Ring-barking.
  • Pollarding
  • Ride, glade and watercourse management.

We consider the following woodland communities within our management plans…

Tree Communities

Genetically many trees within an ancient woodland will be direct descendants of those in the original forest. Our aim is to maintain a natural community of trees by natural regeneration and where this has proved impractical, we are planting local provenance trees for the benefit of biodiversity. This includes shrubs for our borders, ensuring flowers and fruits are abundant throughout the seasons.

The many oaks in our woodland require space and light, they are thin, tall with small crowns. We are selecting at least 1 in 5 trees to be thinned in year 1 and opening up other areas for regeneration. We are retaining trees with good crown potential and ones that show great benefit to associated wildlife. Decisions on where further thinning is required will be made in year 2. Some trees such as our larger sycamores will be and have been ring-barked, creating more standing deadwood.

Ground Flora

We are thinning the woodland and creating openings for the light to penetrate the ground. Hoping the seed bank regenerates with more species currently absent and our current woodland plants have more luxuriant growth and longer flowering periods. We are concerned by agricultural run off that may be affecting our soil with too much inorganic nitrogen. This is not yet proven but being monitored post our canopy management.

We have also sought information to manage the dominant Hemlock Water Dropwort in our marsh area. We will be manually or mechanically digging it out in June 2020 according to techniques from the Centre for Ecology and Hydrology.

Epiphytic Flora and Fungi

This community relies on a number of woodland attributes: This can be shade for the bryophytes, light for the lichens, decaying wood for fungi and moisture for all. We are lucky to be in the “wet” South West where epiphytic communities thrive in our unpolluted atmosphere. We also benefit from the important Atlantic Woodland flora specific to the West of England’s temperate rainforest. Angie has trained as a Bryophyte botanist as well as attending numerous Lichen/Atlantic woodland courses to ensure we embrace our micro habitats within our holistic approach to woodland management. Nigel has the experience in our tree fungi as well as pests and diseases, whilst ground and deadwood fungi remain an ongoing interest of us both.

Saproxylic Invertebrates

This community depends on dead or dying wood. We prioritise dead wood within any woodland habitat, we leave most of our felled oaks where they fall and never fell standing deadwood. We have recently ringbarked some of our larger sycamores to gain bigger diameter standing deadwood than our woodland currently offers. This also gains light in those areas for regeneration of our native trees and ground flora. The thinning of our compact and overpopulated oak, gives us more ground deadwood to replace some of the already very decayed wood on the ground. Whilst some are left where they fall, we use others to border trails and make shelter. Oak being long lasting and no treatment needed, it allows the structures to eventually decay like any other deadwood.

Butterflies

Most species of woodland butterflies live in the open areas of rides and glades. In small woodlands, It is unrealistic to consider anything more than a large ride or small glade/opening. We are maintaining our ride and creating openings for regeneration. In approx. 5 years when this regrowth is established, we will consider the location of the next opening.

We have observed a large adult population of Silver-washed fritillary in our woodland. They appear out of the leaf litter in mid-summer and feed on the nectar of our bramble. Careful consideration needs to be taken in summer to ensure the foot fall stays in areas where they are not resting in abundance and we do not strim at this time of year.

Mammals

Unlike most management plans which mainly consider the habitat for dormice, red squirrels and bats, we consider the safe environment for our larger and predatory mammals as well. A woodland is their main habitat and mammals are an important part of the ecosystem. We should ensure populations remain healthy and the environment enriched with food.

A great deal of woodland wildlife is managed and hunted, including deer, badgers, foxes, rabbits and squirrels. I appreciate populations are successful, however:

Our woodland which we manage for all wildlife, has not got an excessive or destructive population of any particular species.

  • Our Roe Deer do browse but not yet proven to be to the detriment of regrowth. We are protecting saplings and newly planted trees to be entirely confident. We have several resident deer, seen often in our cameras, we have three known fawns grow up in 2019 and still remain playing in the wood early 2020.
  • Grey Squirrels like red squirrels do cause damage, but for our woodland which is not managed for timber, the current amount of damage caused is necessary for other wildlife such as bats and some woodpecker species to thrive. We know of no introduction plan for reds in the area and the isolated nature of our broadleaved woodlands is not suitable habitat, we believe reds will not gain a stronghold here. Whether Idless woods could support them is a matter we have not yet been informed about.
  • Our badgers as in any woodland, are at the peril of the surrounding farmland if they choose to cull. To understand the problem and right solution to eradicate TB in cattle, Angie trained as a badger vaccinator with the APHA. Before our ownership, good populations of badgers lived in the numerous big setts but most of the setts were inactive before we took it over. Potentially due to an air rifle target practice occasionally held before we purchased. However, badgers currently use our woodland as a large part of their habitat. We monitor badgers at their runs and latrines and use peanuts on occasions as an encouragement tool. We welcome them back as full residents.
  • Foxes are resident and use old badger setts. We have witnessed off spring in 2019. Another mammal important for a thriving healthy ecosystem. We are communicating with the hunt that use the area to ensure they know in no uncertain terms; they are not permitted near our woodland.
  • We have not personally recorded bats in the woodland but a local ecologist has suggested that Brown Long-eared bats are present in the area. We carefully select trees that do not make good habitat for bats when thinning. We will, if and when required, seek advice from expert ecologists in this field.
  • We have not yet observed any signs of dormice and our shrub habitat in not currently ideal. We have also been informed that they have not been recorded in this area of Cornwall for many years. Our small area of Hazel will be coppiced over the coming three years and we will observe information of any potential re introduction in the area.
  • Our rabbits are not a large population, but all appear healthy.
  • We have only witnessed a couple of Stoats near the marsh. We don’t yet know if they are resident. 

Birds

Managing the layers and age structure of a woodland is a priority when considering healthy bird populations and species diversity. Our woodland has both upper Oak woodland and wet woodland which is encouraging for a range of species. However, with a predominantly Oak and holly woodland and a limited shrub layer, we are currently working on introducing a range of other native tree and shrub species whilst opening up the canopy. These species will enhance the flowering period and autumn berries for winter feeding birds. We have also been asked to retain the Willow/Alder carr as it currently stands, to encourage the Pied Fly Catcher.

Many of our birds are only observed through the song above. We are training ourselves to know the species high up in the canopy. We have good populations of black bird, song thrush, redwing visitors in January, woodpeckers, many Jays, nesting buzzards and at least one breeding pair of Tawny Owls.

Check out our species list for the woodland here: Happy Habitats Woodland Species List


Woodland Management Methods

Coppice. Its ecological value.

Coppicing produces a light environment similar to that of a young natural forest or from a gap created when a mature tree falls.  In the early stages of a  coppice cycle the ground flora is rich and butterflies abundant. Temperature to the ground is higher, moisture in the soil lower and increased light.

Animals such as Dormice thrive in coppice management as they feed on nuts, berries and invertebrates. Periods of coppicing are important to note. For example, hazel takes around 8 years to produce nuts, therefore a coppice rotation would need to be 15-20 years.

Our Sessile Oak woodland is an ancient woodland that has been coppiced for at least a few hundred years. We know it has been harvested to produce charcoal but neglected for many decades.

As a small woodland and a neglected coppice, we have opted out of this method of future management as a whole, but we are coppicing many trees such as our sycamores to stop seed dispersal and generate openings in the canopy.

The young regrowth of the coppiced trees will act as a low sub canopy layer for birds whilst our desirable regrowth, planted trees and shrubs become more established.

Ancient Woodland, Old Growth Forest.

Management of old growth forests require less intervention, allowing dead wood to accumulate and a natural woodland structure to form. Where trees die and fall naturally, not only does this create openings in the canopy, but the dead wood generates suitable habitat for fungi, lichens, bryophytes, invertebrates and associated fauna such as birds and bats.

Our aim is to restore the natural vitality of a woodland, an attempt if you like to restore its future health as the natural woodland it likely once was. The future of our woodland beyond our time is then more likely to manage itself as an old growth forest with minimum intervention needed.

Dead wood habitat can be recreated by leaving log piles or ring-barking selected trees to give standing dead wood. We use the ring-barking technique on our non-native trees such as sycamore. Our log piles are generated from the much-needed thinning of our overpopulated oak coppice.

The thinning of our woodland will also help the ground flora to thrive while allowing light to reach the floor. Ancient woodland ground flora is rich with species such as bluebells, primroses, wild garlic, yellow archangel, wood anemone, wood sorrel, dog’s mercury and many ferns which are all classed as ‘ancient woodland indicators’.

We will be managing our main ride and creating openings/small glades to mimic fallen old trees using the above techniques.

Natural Woodland

Britain has no virgin Forest, so we have chosen our woodland due to its potential as an ancient oak woodland but neglected coppice. Although its smaller than one would want in such a project, we want its future to be as similar to a natural woodland as much as it is viable. Careful consideration has to be made over our initial intervention and non intervention, to help develop valuable habitat for species dependent on mature trees.  We also need to consider that even large woodlands will be influenced by their surroundings such as pesticides, invasion of edge species and air pollution. Not forgetting Britain has lost many of our large mammals.

A huge benefit to us as woodland owners and the surrounding communities, are the educational opportunities a project like this can provide. By monitoring environmental changes, sharing the natural dynamics of a woodland and creating the wilderness atmosphere missing from our environment as whole.

High Forest

High forest is woodland that has a closed canopy (unlike coppice or old growth woodland) and has far less biodiversity. It is usually under some form of management for timber production rather than conservation and therefore: same aged, one or few species, a lack of shrub layer, dark throughout and dead wood is often removed.

Occasionally these woods are managed for recreational benefits. Management can therefore incorporate techniques to enhance biodiversity. Such as:-

  • Encouraging natural regeneration of native tree species.
  • Creating a diverse age structure and good shrub layer through planting and regeneration.
  • Protecting some of the large mature trees
  • Retaining standing and fallen dead wood.
  • Removing invasive species such as Rhododendron.
  • Managing other habitats such as tracks, glades and streams.
  • Ensuring that forestry operations have minimum negative impact.

Wood Pasture – Grazing & Pollarding

Some of our oldest trees are situated sporadically throughout our parks, estates, grazed common land, royal forests and medieval deer parks.

On these sites, stopping or even relaxing grazing can be very damaging to the epiphyte community of such old woodland sites, as well as certain bird species who do not do so well in dense undergrowth.

Pollarding has been very successful in producing many of the magnificent ancient Beeches and Oaks in lowland wood pasture which are rich in Epiphytes and saproxylic communities.

It is desirable to continue the pollarding tradition on young or middle-aged trees which benefit from an unshaded environment. Prolonging the life of the tree for future generations and woodland communities to benefit.


Shrub and sub canopy management

The above techniques will assist the development of the shrub and sub canopy, through regeneration and will increase the age diversity. The light created through thinning, coppicing and ring barking is also allowing us to plant shade intolerant shrubs and pioneer species.

So far we have group planted silver birch, planted downy birch in the wet woodland and planted mountain ash throughout. We have also added a few crab apples and a group of small leaved lime. Guelder Rose has been introduced to our woodland edges and central ancient wall as its also shade tolerant and spindle has been added to the hedges and borders.

Rides & glades

Rides can be managed by crown raising and veteranisation techniques to imitate damage to benefit wildlife habitat. Some coppicing of oak is also taking place to widen the rides to 1.5 x the height of the trees. The bordering regrowth will be cut every 4 to 7 years.

Glades will be monitored for regeneration, regrowth and the bramble managed.

Marsh and Stream

Our wet woodland consists of Willow/Alder Carr and is being monitored for any improvements. However, we have open marsh areas which is dominated by Hemlock Water Dropwort. This will be managed in May/June after its most toxic period through late winter early spring. It will be dug out according to the Centre of Ecology and Hydrology and disposed of by drying and burning.

We have identified many other wetland species and the removal of dominating species, will enhance this floral habitat where insects and birds benefit from the open canopy next to the stream. We have started manual pond creation and observing the benefits being created. This work continues as per our 3 year FS woodland plan, along with exciting wildlife installations such as an otter holt to come.

We have also considered the possibility of agricultural run off being the cause of nettles and Hemlock Water Dropwort, we are seeking further advice from organisations such as the Westcountry Rivers Trust.

Check out our species list for the woodland here: Happy Habitats Woodland Species List

* We appreciate that badgers have protection, but the damage caused by the cull far outweighs the benefit of this protection. 

About the author: Angie Cruse

As well as working hard on the ground here in the UK, Angie has spent ample time volunteering in conservation abroad and continually studies habitat management in conservation.

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