Ecological restoration of conifer forests

14 September - 15 September 2006

University of Wales, Bangor, Gwynedd, UK

There have been many recent developments in the restoration of conservation and landscape value to uniform conifer plantations in North Wales.  This meeting will include one and a half days visiting ecologically contrasting conifer forests in North Wales where alternative restoration methods are being implemented.  The remaining half day will consist of oral and poster presentations relating to the following themes of the meeting:

• alternative restoration and monitoring methods from habitat to landscape scale
• restoration of Plantation on Ancient Woodland Sites
• species conservation in conifer forests, including black grouse, red squirrel and fritillary butterflies
• Continuous Cover Forestry in the context of restoration

Accommodation in Bangor will be provided on 13 and 14 September, but it can also be provided on request on 15 and 16 September.

As soon as further details about the meeting are available they will be posted on a web-site accessible from http://www.safs.bangor.ac.uk/.

The organisation of the meeting is being led by Dr Arne Pommerening.  At this stage expressions of interest to present papers (orally or mainly as posters), and to attend the meeting are invited to arne.pommerening@bangor.ac.uk

In addition to these BES meetings, members might be interested in attending a conference on ‘Woodland birds in a changing environment’ being organised by the British Ornithologists Union in April 2006. Details at http://www.bou.org.uk/meetgen.htm

British Ecological Society – Forest Ecology Group
Bramble in Woodland - bane or benefit?

The following are very brief notes of the presentations made at this meeting which was attended by almost 50 people, most of whom were involved in the practical management of bramble.

Ralph Harmer
Forest Research
Email: Ralph.Harmer@forestry.gsi.gov.uk

Distribution and ecology of Bramble

Keith Kirby
English Nature
Email: Keith.Kirby@English-Nature.Org.UK

Bramble is a very common, successful, native species that occurs in a wide variety of habitats throughout Britain including woodlands, heaths, dunes, mires and grassland.  Several features may explain the success of bramble: it can survive long periods in the seed-bank; spreads vigorously by vegetative growth; is semi-evergreen – in mild winters the leaves persist on first year canes; can be spread long distances by birds.  In favourable conditions it can grow to produce dense thickets that can have adverse competitive effects on other vegetation.

It is a component of all woodland and scrub communities except Native Pine Woodland (W18) and two types of upland scrub (W19,W20).  The recorded frequency of bramble within woodland communities varies and it tends to be less frequent in upland compared to lowland woods.
For example, it is scarce in upland ash and oak woods (W9 and W11) but constant in the lowland equivalents (W8 and W10).  The abundance of bramble is related to soil quality, light and the intensity of grazing.  It is often abundant on sites with base rich, mesotrophic soils, but growth is restricted by dense shade.  It is a palatable species that is eaten by a variety of herbivores, which may help explain its reduced frequency/abundance in NVC woodland communities associated with the uplands, as these were often heavily grazed in the 1970’s when the NVC’s vegetation surveys were carried out.

Bramble cover in woodland is often dynamic with abundance being generally related to changes in canopy cover and browsing pressure.  This results in variable bramble cover throughout a woodland in both location and time which is of benefit to the overall diversity present.

Growth, Flowering and Fruiting

Andrea Kiewitt
Forest Research
Email: Andrea.Kiewitt@forestry.gsi.gov.uk

The shoots of bramble are biennial, growing from a perennial root-stock – they remain vegetative in the first year forming flowering lateral shoots in the second.  Daughter plants may be produced vegetatively from fiirst year canes which can root at their tips during the autumn.  An experiment was carried out over 3 years to investigate how different levels of canopy cover, created by thinning treatments within a stand of 35-year-old Corsican pine (10,20,40,80% of basal area removed), influenced vegetative growth, flowering and fruiting.

A non-destructive method was used to assess the cover, height and length of bramble shoots.  All increased roughly in accordance with the amount of basal area removed, but treatment differences were not always significant. It was possible to predict bramble growth from the basal area of trees remaining after thinning.  Fruiting was observed by assessing the number of berries and filled seeds produced during late summer.  The number of fruits on each inflorescence was unaffected by canopy cover, but both the number of inflorescences and number of berries per square metre was positively related to intensity of thinning (i.e. more light, more fruiting).  Although fruit development was more advanced under the heavier thinning, there was no effect on the number of seeds in a berry nor the proportion of filled seeds.  Whilst bramble can grow beneath a canopy, its vigour and reproductive success is reduced.

Better growth, flowering and fruiting under reduced canopy cover may bring benefits to some wildlife, but these must be balanced against adverse competitive effects that bramble may have on tree regeneration and small plants in the ground flora.

Rubus – who needs sex?

Clive Stace
Leicester University

Reproduction in plants may be sexual or asexual.  Typically seed production is sexual but there are many plants which are apomictic – reproducing by seeds that are produced asexually and are entirely maternal in origin – these include dandelions and brambles.  Apomictic brambles are polyploid and their expression of apomixis is facultative – with plants being able to reproduce sexually, apomictically or by both means which allows new types to develop by hybridisation.  In addition, they all, of course, reproduce vegetatively.  Seed production by apomixis can occur in a variety of ways. In brambles both apospory and diplospory occurs, but in addition pollination is required in order to generate endosperm. This is termed pseudogamy, and means that brambles have to produce pollen to achieve it, in contrast to many other apomicts such as most dandelions, in which pollen production does not occur.

Because of their asexual mode of reproduction, brambles have diversified and produced a great number of taxa (over 320 in Britain) which, with much practice, can be recognised by experts.  These microspecies differ in their habitat preferences and ideally managers should be able to identify those present on a site.  However, identification of different microspecies can be very difficult and there are few capable of the task.   In order to identify a microspecies it is necessary to look at both flowering and non-flowering stems observing a wide variety of features including leaves, prickles, glands, flower characters and young fruit.  Mature fruits are of relatively little value in identification.  It is not necessary for a local botanist or forester to be able to recognise anything like 320 species; for example, only about 120 are recorded for the whole of Gloucestershire. It is suggested that he collect a good sample of each sort in his area, and that he get these determined by an expert so his collection can be used as a reference in the future. In this way the (say) 20 or so species present in a woodland site can soon be learnt.

Birds and other wildlife

Chris Hewson and Rob Fuller
British Trust for Ornithology
Email: chris.hewson@bto.org

A variety of wildlife resources are provided by bramble, these include both food (nectar, pollen, flowers, fruit, leaves) and physical structure that provides habitat in which to live.  About 240 species of phytophagous insects and mites feed on bramble; 32 of these rely exclusively on bramble and 12 have red data book status.  The adults of saproxylic insects also use the flowers of bramble when those of their main food plants – often hawthorn – are over.  Bramble is a very valuable species for dormice: they nest within the bramble thicket; they eat the flowers and the insects attracted to them and consume the berries produced in autumn.

Birds utilise bramble in a variety of ways as it is: a key nesting site for several species (e.g., song thrush and wren); an important component of the habitat providing cover and protection from predators (e.g. nightingale); provides berries which are an important source of food especially for pre-migratory fattening (e.g. Sylvia warblers).  The shoots and leaves of bramble provide food for large herbivores such as deer whose browsing activity can have significant effects on the growth and development of the bramble thicket.  Consequently high numbers of deer or other animals that create overbrowsed woodlands will reduce both food supply and structural in which birds live, nest and take cover from predators.

Although in some circumstances bramble can be a problem it is often of benefit.  It provides many resources and is a key structural component of habitats for birds in many woods.

Practical aspects of management

Rik Pakenham
Chiltern Forestry
Email: cforest@psa-online.com

If bramble is managed it can have a number of positive benefits, for example: as a food plant for many animals; by providing a protective/structural habitat in which many species live; retaining moisture and influencing microclimate at ground level; protecting planted and naturally regenerating trees from browsing animals.  In addition it can provide a living hedge to restrict or zone public access on a site.  However, if it is unmanaged, bramble can have serious negative effects: natural regeneration can be limited; the development of the ground flora can be suppressed with consequences for diversity; it can physically smother plants e.g. pulling-down both planted and naturally regenerated trees; it may restrict access for maintenance operations.
There are 5 options for control: careful manipulation of over and understorey cover to control light level at the forest’s floor; tractor mounted cutters, pedestrian operated cutters; herbicides; tractor mounted combing using a modified spring-fire cultivator.  The future for the use of herbicides is unclear.

Field visit
Rik’s presentation took place at an experimental site within a neglected ash – field maple coppice woodland where the effects of different stand management treatments on the regeneration of trees and the development of the groundflora is being investigated.  The treatments include different intensities of thinning, fencing and control of bramble.  For more information about this site contact Gary Kerr or Ralph Harmer of Forest Research.
Email: Gary.Kerr@forestry.gsi.gov.uk.

BES meeting “Ecological restoration of conifer forests: research and applications”

University of Wales, Bangor - 14/15 September 2006

A total of 52 people from a wide range of organisations including Butterfly Conservation, Woodland Management, and Forest Research met at Bangor in the second week of September to discuss the potential synergy on conservation/restoration of woodlands, through the cooperation of ecologists, forest scientists and forest managers. The meeting began on the evening of Wednesday 13th September with a reception addressed by David Wright, head of the School of the Environment and Forest Sciences. There were indoor sessions in the mornings of the following two days and field excursions in the afternoons. Ten speakers including Professor James P. Kimmins from the University of British Columbia and Dr Roque Rodríguez from the University of Santiago de Compostela (Spain) gave informative and challenging presentations covering various aspects of ecological restoration. Topics included harvesting in the natural disturbance ecology, the potential role of conifer plantations in the restoration of biodiversity, PAWS restoration and herbivore impacts, wind as a constraint to gradual restoration and butterfly conservation. All presentations can be reviewed on the Tyfiant Coed website at http://tyfcoed.bangor.ac.uk. The field trip on 14th September visited Coed y Brenin (Coed y Mynydd Forest District) and looked at different approaches to restoration ranging from a gradual method to a more radical and instant removal of conifers. After an introduction to the forest and the vision of the District by local area manager Aled Thomas there was a lively debate on the philosophical, ethical and practical implications of restoration. The participants also visited the permanent monitoring plots of the University of Wales, Bangor (Tyfiant Coed project) and had a short introduction to the Meirionnydd Oak Woodland Project. Friday’s excursion started with an introduction to the butterfly and red squirrel conservation projects at Clocaenog forest (Coed y Gororau Forest District). The District Planning Forester, Richard Carrick provided the group with a broader perspective on the challenges facing the future management of Clocaenog. Finally delegates were able to examine a joint University of Wales, Bangor/Forest Research experiment demonstrating several approaches to transformation of Sitka spruce plantations to continuous cover forestry (Tyfiant Coed project). The meeting was co-funded by the British Ecological Society and the Forestry Commission, Wales.

Adrian Newton

anewton@bournemouth.ac.uk