Plan Summary

Trawscoed is a small nature reserve, 67 ha in size, which has been designated a Site of Special Scientific Interest and is managed by the Meirionnydd Wildlife Trust. The site comprises three rocky ridges which are covered by broadleaved. oak-dominated wet woodland. There are occasional, small, bracken-dominated glades and a few acidic flushes. The canopy is overwhelmingly dominated by sessile oak Quercus petraea, except for the base of the various inclines where ash Fraxinus excelsior is also an important species. In addition to the woodland habitat, the only other important biological feature is a population of lesser horseshoe bats. The reserve provides limited access opportunities for local people.


Legislation


Legal Status of Site

SSSI Trawscoed was notified as an SSSI in 1960 and enotified in 1986. The SSSI features are:


Oak woodland

W17 Quercus petraea/Betula pubescens/Dicranium majus woodland

W17b Typical sub-community

W17c Anthoxanthum odoratum/Agrostis capillaris sub-community


Lesser Horseshoe Bats

Rhinolophus hipposideros


Oak Woodland

The oak woodland is a Natura 2000 Annex I habitat: 91 AO Old sessile oak woods with Ilex and Blechnum in the British Isles.


This habitat type comprises a range of woodland types dominated by mixtures of oak Quercus robur and/or Q. petraea and birch Betula pendula and/or B. pubescens. It is characteristic of base-poor soils in areas of at least moderately high rainfall in northern and western parts of the UK.

Lesser Horseshoe Bats

This species is included in Appendix II of the Bonn Convention (and its Agreement on the Conservation of Bats in Europe) and Appendix II of the Bern Convention (and Recommendation 36 on the Conservation of Underground Habitats). It is also listed on Annexes II and IV of the EC Habitats and Species Directive. It is protected under Schedule 2 of the Conservation (Natural Habitats, etc.) Regulations 1994 (Regulation 38) and Schedule 5 of the Wildlife and Countryside Act 1981. The 1996 IUCN Red List of Threatened Animals classifies this species as Vulnerable (VU A2c). (UK Biodiversity Action Plan)


Other Relevant Legislation

Occupier's Liability Act

This Act imposes on the Trust an obligation to ensure that every reasonable care is taken to remove any risk both to legitimate visitors and to trespassers. A safety audit must be carried out on this site and updated as required. The Trust must ensure that the site hazard assessment is available to people using the site, for example, for research purposes, and that all relevant personnel are issued with a licence.

Health and Safety at Work Act

The Trust has a duty under this Act to ensure the health and safety of its staff when engaged on official business. All operations carried out on site must be undertaken by trained personnel using methods and equipment which comply with Approved Codes of Practice arising from the Health and Safety at Work Act 1974, and also in compliance with both national and local safety procedures (i.e. the Trust Safety Manual). The need for an up to date hazard plan and for regular safety inspections also applies here.


Public rights of access

The access road to Trawscoed is a public highway, but no public footpaths cross this reserve and there are no permanent rights of access for the general public.


Policy

The Meirionnydd Wildlife Trust policy for the management of nature reserves:

The management of our nature reserves which have statutory protection is guided by the relevant legislation. This policy, whenever applicable, will also be applied to all other Trust reserves. The primary land use of all the Trust reserves will be nature conservation. The Trust recognises a responsibility to maintain or restore the nature conservation features to Favourable Conservation Status. All Trust reserves will be managed to the highest possible standard.


The Trust will encourage the sustainable public use of its reserves in so far as such use is consistent with our responsibility to protect wildlife and does not put any visitors or staff at risk. Visitors will be permitted to engage in activities providing that they are legal, that they are not a danger to other visitors or staff and that the activities do not detract from the ability of other visitors to enjoy the site.


Description


General Information


1 Location and Site Boundaries


National Grid Reference: The centre of reserve is SH444216

Trawscoed Nature Reserve lies approximately 2 miles south of the village of Llanilar and 2 miles north of the village of Cantre'r Gwaelod. The reserve is situated within the district of Meirionnydd in the county of Gwynedd and is within the Snowdonia National Park


National Grid Reference: The centre of reserve is SH444216

Trawscoed Nature Reserve lies approximately 2 miles south of the village of Llanilar and 2 miles north of the village of Cantre'r Gwaelod. The reserve is situated within the district of Meirionnydd in the county of Gwynedd and is within the Snowdonia National Park


2 Zones


For the purposes of management the site has been divided into eight zones. These are based on a comination of the tenancy bouindaries, habitat types and management requirements. Zones are indicated on the attached map and include the following:


Cadair Rhys Goch

Bryn Twr

Bryn Twr Extension

Parc Mawr

Hafod-y-Llyn-isaf

Coed Hafod-y-llyn

Llyn Hafod-y-lyn

Trawscoed


3 Tenure


The reserve is owned by the Trawscoed Estate and has been leased by the Meirionnydd Wildlife Trust since 1992.


4 Past Status of Site


Trawscoed is a Nature Conservation Review Grade 1 site


5 Management/Organisational Infrastructure


The site is managed as a nature reserve by the Meirionnydd Wildlife Trust. The Trust employs six full-time staff and is also supported by a considerable contribution from volunteers. This responsibility for managing Trawscoed is currently delegated to the Senior Reserves Manager, who manages a team of two estate workers and is also responsible for seven other woodland reserves. Contract labour is employed to carry out capital works such as fence-line replacement and rhododendron control.


6 Site Infrastructure Boundaries


Since 2002, the entire external boundary and all internal compartment boundaries have been fenced. Gates and stiles are provided wherever necessary. All fences are in good condition, having mostly been replaced or erected relatively recently. There is a planned programme of replacement.

Buildings

There is a large barn and a smaller building adjacent to each other near Trawscoed House. The 'studio', known as Ysgubor, is used as a working base for the Estate Worker, and the upper floor of the barn is used for storing tools and materials for use on site.

Roads, tracks and paths

There is an unclassified road which runs the length of the site along the eastern boundary. A small car park at the southern extremity of this road has space for four cars. 500m west of this, on the opposite side of the river, a parallel track provides vehicular access to the buildings at the centre of the reserve. There are no public footpaths on the nature reserve, but there are several paths and tracks within the site.


7 Map Coverage

The following maps, or copies of maps, are held in the reserve files. Contour maps

1:5() (XX) Ordnance Survey Landranger No. 124 Dolgellau and surrounding area 1991 1:25 (MX) Ordnance Survey Outdoor Leisure No. 18 Snowdonia - Harlech and Bala areas 1990

Edition of 1916, 2nd Series Ordnance Survey map, Meirionethshire sheet III. 13 Soil Survey of England and Wales, sheet 2 - Wales 1983.

1 inch Geological survey, Sheet 65 NE. 1851 and 1854. Uses 1840 sheet as base. Land Utilisation Survey 1931-32. Copy in National Library of Wales, Aberystwyth. Land Utilisation Survey 1971. G. Sinclair. Copy held at the Trust office.


8 Photographic Coverage


Fixed Point Photographs:

A series of rotational pans was taken in March/April 1989 on 35mm black and white print film from 24 different fixed points. These cover much of the southern half of the reserve, including Bryn Twr, Pare Mawr and the area to the west of Pare Mawr. Details of the location of each fixed-point and the contact prints are held in the photo-monitoring file. The negatives are held in the Trust office.

General photographs: Various 35 mm colour slides of the site are available. These need to be collated and evaluated.


Aerial photographs:

A selection of aerial photographs is held in the reserve files. Dates: May 11946. September 1971. October/November 1986, June 1993


Environmental Information


Physical


Climate

The following information on climate is based on meteorological information recorded at Cantre'r Gwaelod, which is approximately 1 km north of the site.


Temperature: Temperatures may vary between an absolute minimum of around -8C and a maximum of around 30 C. February is the coldest month, with a mean daily temperature of about 4-5 C. July is the warmest month, with a mean daily temperature of 1415C. The frost-free period generally extends from mid-April until November.

Rainfall and snow: The mean annual rainfall is 2,121 mm. The wettest period is from August through until March (though February is generally drier), and the driest months are May: June and July. Snow falls on an average of 15-17 days a year, with January, February and March being the most likely months.


Sunshine: The average daily duration of bright sunshine is about 4h, and the annual average percentage of the possible sunshine is about 30%.


Wind: The strongest winds tend to occur between September and March, and these are likely to be contained within an arc between south and north-west, southwest being the strongest. The maximum gust speed recorded is between 70 knots and 80 knots. The site is afforded some protection by the mountains to the north and west, but is fairly open to winds blowing up the estuary from the south and south-west.


Geology

Trawscoed lies at the western edge of the geological area known as the 'Harlech Dome'. This is an area of uplifted and eroded geology exposing the largest area of Cambrian sedimentary rocks in Wales. It has been surveyed by numerous geologists and is well documented, including a report by the British Geological Survey (Allen and Jackson 1985).


It is thought that the initiation of this present day structure occurred during the Caledonian Orogeny. Pressure from the south-east against the ancient rocks to the north (now Anglesey) caused the uplift of the younger rocks in the Meirionnydd region in the form of a dome extending roughly from the River Mawddach to the River Dwyryd. Subsequent erosion has exposed the older Cambrian rocks in the central area of the dome, with the younger Ordovician igneous rocks remaining around the periphery. These later rock types form the bulk of the mountains surrounding the Rhinogau range, e.g. Snowdon and Cader Idris.


Trawscoed is situated in the western section of the Cambrian rocks of the dome. The rocks are all slates, grits and shales of the Harlech Grits group, consisting mainly of shales and mudstones of the Maentwrog formation. These arc relatively fine-grained rocks, quartz-rich and in flaggy layers. There are also basic Doleritic intrusions, providing a range of pH conditions. The Cambrian rock formations are base-poor, hence the generally acidic nature of this site. There are, however, some localised areas of base-flushing, probably caused by groundwater passing through certain of the beds that contain more basic minerals, manganese beds in particular.


Soil and substrates

There has been no detailed survey and analysis of soils on this site. The following account is based on the rather general details provided by the Soil Survey of England and Wales (1983). The main types are podzolic soils and raw peat soils.


The greater part of the site is overlain by podzolic soils: this is the soil type covering the three main rock ridges. These soils result from the pedogenic accumulation of iron and aluminium or organic matter or a combination of these. Those found here are typical brown podzolic soils of the Manod Association. They have developed over Ordovician shales and have a dark brown or ochreous subsoil with no overlying 'bleached' layer. They are well-drained, fine, loamy or silty soils, often shallow with exposed bare rock. While there have been no detailed studies, where larger trees have been uprooted by wind, soil depths have been observed to be little more than 30cm, with deeper roots being entwined with rock fragments. Soil depths on the tops of the ridges are probably less, perhaps 15-20cm.


Hydrology

The reserve essentially comprises three roughly parallel rock ridges separated by two shallow troughs. The ridges are largely wooded and mainly free draining. However, there are some waterlogged areas in the occasional hollows and some areas of flush, notably at the northern tip of the site. The more southerly and deeper trough between Pare Mawr and Bryn Twr is, in fact, the lower end of the Gwaelod valley. A fairly major stream flows through this valley, fed by a relatively large catchment area to the north. This stream bisects the southern half of the site, eventually flowing into the river. Prior to the construction of the Cantre'r Gwaelod embankment (1815) and the reclamation of the estuary, the southern periphery of this site would have verged on the intertidal zones, with the three wooded ridges representing small peninsulas. This is no longer the case: most of the land immediately seaward of the site is now improved grassland.


Biological


Flora


Habitats and communities

The three main rocky ridges are covered by broadleaved, oak-dominated woodland, with occasional bracken-dominated glades and a few acidic flushes. The 'dry' broad-leaved, oak-dominated woodland covering the rocky ridges amounts to a total area of around 66 ha. Most of this is the NVC type W17 Quercus petraea -Betula pubescens - Dicranum majus woodland, including both the typical sub-community type b, and the Anthoxanthum odoratum - Agrostis capillaris sub-community type c.


The canopy is overwhelmingly dominated by sessile oak Quercus petraea (some hybrids, petraea x robur, also occur), except at the base of the various inclines where ash Fraxinus excelsior is an important component. The build-up of minerals through run-off is the probable reason for the difference in these localities; the NVC type is not changed. Downy birch Betula pubescens and silver birch Betula pendula are also important components of the canopy. Rowan Sorbus aucuparia is a frequent addition, while crab apple Mains syivestris and holly Ilex aquifolium occur occasionally, with some particularly large, old specimens of the latter.


There is no detailed information on the age of the woodland stand. Subjective observations indicate that most of the growth dates from around the beginning of the 20th century. There are evidently some areas where the stands are younger, but also several trees throughout the site which are clearly much older (c.200 years).

The drought in 1976 led to the dieback in the crowns of several trees and the eventual death of some. The worst affected areas were along the tops of the various ridges, especially on south-facing locations, where the soils are thinnest and most free draining. The effects of this drought are still apparent through dieback of branches, but most trees have since recovered.


The understorey is much influenced by past grazing and, as with most western oak woods, it is generally sparse. A scattering of saplings/young trees of fairly even age (c. 15-25 years) is present across most of the woodland, suggesting a period of relaxed grazing pressure at some time in the past. The main component of the understorey is rowan Sorbus aucuparia, while sessile oak Quercus petraea, birch Betula spp., hazel Corylus avellana and holly Ilex aquifolium occur frequently. There is occasional beech Fagus syivatica and crab apple Malus sylvestris.


The field layer is short and generally dominated by grasses. The main species are common bent Agrostis capillaris, velvet bent A. canina, sweet vernal grass Anthoxanthum odoratum, sheep's fescue Festuca ovina, purple moor-grass Molinia caerulea and wavy hair grass Deschampsia flexuosa. In compartment 3, where grazing has been effectively removed since 1990, much of the field layer is currently dominated by purple moor-grass Molinia caerulea. The other main components of the field layer are wood-sorrel Oxalis acetosella, tormentil Potentilla erecta, heath bedstraw Galium saxatile, bramble Rubus fruticosus agg. and bluebells Hycacinthoides non-scripta. There are also a number of small glades dominated by bracken Pteridium aquilinum. The ericaceous species normally associated with this habitat type, i.e. heather Calluna vulgaris and bilberry Vaccinium myrtillus, have been largely suppressed by the prolonged period of grazing pressure. Tree seedlings are evident throughout the woodland at ground level.

The ground layer comprises mainly a carpet of bryophytes, though there are some extensive areas of litter. The more abundant species are Thuidium tamariscinum, Polytrichum formosum, Rhytidiadelphus loreus, Dicranum majus and Isothecium myosuroides var. myosuroides.


Species

The flowering plant records for the site were compiled in 1977 (Howells and Ward) and 1980 (Blackstock). The site manager has added to the reserve lists. The list is contained in Appendix 1. It is certainly not complete, and more species are likely to occur. At present, the list amounts to a total of 82 flowering plants, which include 14 tree species, 9 shrubs, 9 grasses (Gramineae), 11 sedges (Cyperaceae) and 4 rushes (Juncaceae). There are no rare or notable flowering plants recorded on the site.


Ferns

The fern records for this site were compiled in 1977 (Howells and Ward) and 1980 (Blackstock). A total of 12 fern species has been recorded on the site (a complete list is contained in Appendix 1). Of particular note is the presence of lanceolate spleenwort Asplenium obovatum. A total of 10 plants was recorded at two localities in 1980, both being rock crevices on steep, west-facing rocks under moderate tree cover. This is a nationally scarce species, with its distribution in Britain being confined to coastal areas of Wales and south-west England.


Bryophytes

D. A. Ratcliffe compiled a list of bryophytes for this site during a visit in 1977. Some additional species have since been recorded by the site manager. A complete list of all mosses and liverworts recorded to date is contained in Appendix 1. It is certainly not complete, and many more species are likely to occur.


Much of the site is grazed by sheep and/or cattle and, in some areas, by horses/ ponies. As a consequence, bryophytes are a major component of the woodland ground flora throughout, forming a luxuriant bryophyte carpet. To date, 53 species have been recorded, of which 35 are mosses and 18 are liverworts. Two of the mosses, Rhabdoweisia cremdata and Leucobrywn juniperoideum, are nationally scare oceanic species. A liverwort, Cryptothallus mirabilis, is also nationally scarce (after Hodgetts 1992). Trawscoed is one of the few sites in Britain where Leucobiywn glaucum has been seen in fruit. The woodland communities are characterised by a consistently rich bryophyte ground layer, in which six of the eight constants of the field and ground layer are mosses: Dicranum majus, Plagiothecium undidatum, Polytrichum formosum, Rhvtidiadelphus loreus, Hylocomium splendens and Pleurozium schreberi. All of these, together with Thuidium tamariscinum and hothecium myosuroides var. myosuroides, make up the more abundant mosses in the Trawscoed woodlands.


Certain moderately Atlantic liverworts occur in abundance, notably Bazzania trilobata, Plagiochila spinulosa, Saccogyna viticulosa, Scapania gracilis and Lepidozia cupressina. This indicates that conditions in the woodland are currently favourable for oceanic species which require a shaded and moist environment. During his 1977 visit, D. A. Ratcliffe noted the apparent absence of species such as Plagiochila punctata, Adelanthus decipiens and Lepidozia pinnata. This suggests a period of forest clearance in the past, during which many of the sensitive shade- and moisture-loving species were eliminated. When tree cover was subsequently reestablished, only those species with a strong capacity for spreading were able to recolonise. Species with a poor capacity for spreading have not managed to return (Ratcliffe 1977).


Lichens

A survey of the lichen flora was made in November 1974 and June 1978 (Pentecost). A full account, with a species list, is included in Appendix 1. A total of 99 species was recorded: of these, 87 were of the corticolous type, i.e. growing epiphytically on bark. The saxicolous lichens, i.e. those growing on rocks, were generally typical of species found in acidic conditions. Two of the species recorded rank as nationally scarce (after Hodgetts 1992): Lecidea phaeops and Parmelia horrescens. The list also includes several species which are strongly Atlantic in distribution, Lobaria laetevirens, L. scrobiculata, Parmelia taytorensis, Sticta limbata and S, sylvatica. Only 16 of a possible 70 lichens 'indicative of ecological continuity' occur (after Hodgetts 1992), possibly suggesting a period of forest clearance in the past.

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Fauna

There has been no systematic survey or recording of mammals on this site. Grey squirrel are abundant. Fox and badger frequent the reserve and there are several badger sets. Otter spraint is found regularly on a rock in the outflow from Llynddu, indicating a good population in the valley. There is no information on small mammals.

There is a large and important breeding roost of lesser horseshoe bat in the upper room of the barn within the farmyard complex of Trawscoed House. There are at least seven other known breeding roosts within the Valley for this species, and it is possible that this may qualify the valley for SAC designation for its population of lesser horseshoe bat.


Birds

A total of 38 species has been recorded on the site. There is no information on breeding populations. A full species list is held in Appendix 2. The list includes a number of Candidate Red Data Book species: buzzard, snipe, swallow, dipper, redstart, whitethroat and raven.


Invertebrates

This site supports an impressive invertebrate fauna. This has been comprehensively surveyed, with over 400 species recorded to date. Most of these records were compiled by H. N. Michaelis and M. J. Morgan between 1978 and 1980.

Butterfly species of local interest include green hairstreak Callophrys rubi, purple hairstreak Quercusia quercus and small pearl-bordered fritillary Boloria selene.


Several noteworthy moths occur, including three nationally scarce species (Notable A): ringed carpet Cleora cinctaria, large red-belted clearwing Synanthedon culiciformis and ashworth's rustic Xestia ashworthii. A further seven nationally scarce (ungraded) moths have been recorded. These are marsh oblique-barred Hypenodes turfosalis, silver hook Eustrotia uncula, dotted carpet Alcis jubata, Rheumaptera hastata, Hypenodes humidialis, Tetheella fluctuosa and Alcis jubata..


Cultural


Archaeology

Trawscoed is of considerable historic interest. A 'mansion' stood here in the late medieval period when it was owned by the poet Rhys Goch Eryri. He supported Owain Glyndwr in his rebellion of 1400-1404 and, according to local tradition, it was while Glyndwr was a guest of Rhys Goeh that they were betrayed by a local supporter of the king and escaped in servants' clothes, with the English soldiers in close pursuit, to a cave on Moel Hebog. Some of Rhys Goch's work (31 poems survive) was said to have been composed in a tower on the hill above the house which became known as Gadair Rhys Goch. This had become ruinous by the last century, and the stones were reused in the 1970s to make a seat, which is now overgrown. On one hill within the woods, Cadair Rhys Goch, there are several very small enclosures marked out by lines of fallen stones representing the remains of low walls. They are certainly ancient and possibly prehistoric.


Pare Mawr was described in the last century as coedwigfa unig ac anhygyrch...le am... feudwyaeth a llonyddwch...hen goedyddyn gwyro o henaint teg (a lonely and inaccessible plantation - a place for hermitage and tranquillity with old trees bowed over with fair age.


Past land use

The old wall system suggests a long association with pastoralism. There are several level areas of ground, apparently built up on the lower sides, which have very distinctive ridges and furrows. These possibly indicate early or peasant agricultural use in these locations.


Historical maps provide some information on past land use. The 1st edition OS map (1839) shows the boundary of the Pare Mawr woodland, but there do not appear to be any tree symbols (although this may, in fact, be due to deterioration of the map in question). The 1899-1914 1:25 000 OS map also shows the boundary of Pare Mawr woodland and in this instance there are tree symbols, indicating that the area was wooded at the time. More recent 1:25 000 OS maps, 1912-1914 and 1949. both show the site as largely wooded and/or with areas of rough pasture.


Present land use

The site is managed as a nature reserve.


Past management for conservation

Tree planting - Cadair Rhys Goch

Several oak seedlings and saplings (30-50) have been planted in the woodland on Cadair Rhys Goch by the owner. These have been grown from native seed and vary in age, the oldest being 20 years. In February/March 1995, the Trust planted a further 60 trees in compartments 1 and 2.

Woodland exclosure

The south-eastern quarter of Bryn Twr (compartment 3) was made stockproof in 1989/90. and stock have since been excluded. The rest of the woods were made stockproof. and most sheep excluded, in early 2002.


Rhododendron control

Rhododendron Rhododendron politician became a serious problem in various parts of the broadleaved woodland and is most abundant along the course of the stream. It has been systematically removed from the reserve woodlands, wetlands, and ditch and stream banks, and from adjacent land, since 1994. Control has been successful, although there are still some seedlings and small bushes which have been missed


People


Stakeholders

The owner of the nature reserve

The owner of the site is also the owner of the Trawscoed Estate, which surrounds the site on three sides. The landowner has similar objectives for the site as the Trust. He recognises the importance of the site for its wildlife and habitats.


Adjacent landowners

The owners of the house known as Hafod y Llyn also own 20 acres of woodland contiguous with the reserve woodlands and included within the stockproof fence of the reserves woodland enclosure. Effectively, all their land is managed in the same way as the reserve land. The owners are very sympathetic to the Trust's aims for the nature reserve and are happy for the current arrangement for excluding sheep from their area of woodland to continue.


Local residents

There are very few local residents as the site is isolated and distant from the local villages, both of which are 2 miles away. The few local residents adjacent to the site in scattered farms and houses are kept informed by the site manager about the reserve.


The residents of Trawscoed House take an active interest in the reserve and its wildlife, and are effectively the custodians of the breeding roost of lesser horseshoe bats in the stable block.


The local community

There are centres of local population within 2 miles of the reserve at Llanilar and Cantre'r Gwaelod. The existence of the main reserve has not been actively publicised, and many people are unaware of its existence. A few local people walk there and almost all are very sympathetic to the aims of management.


Contractors

Much of the work on the reserve is carried out by local contract labour. This has included rhododendron control, boundary work, tree felling and safety work, scrub control, lichen survey, engineering work, etc. Contractors will continue to be used, and local contractors are always given preference unless the skills required for the task are not available locally.


Access

This is not an important access site. The roads to the site are very narrow and unsuitable for anything other than small cars. It is not possible to travel to the site by public transport. The site is designated as open access, i.e. there are no access restrictions, and most of the site is accessible on foot to people with average mobility and fitness. The site is visited by less than 50 people each year: these are mainly local people who visit throughout the year but most often during the summer months. People tend to visit for very short periods, usually of about 30min; most of these are dog walkers. People visit mainly for the experience of walking through particularly attractive oak woodland or simply to exercise their dogs.


There are reserve signs at the entrance points, with a reserve map showing the pathways and tracks, basic information about the site, and health and safety information.


There are occasional visits by scientists and specialists: these are recorded in the management plan.


Given the difficulty of providing access to the site, and the presence of so many similar sites with well-developed access provisions in the immediate area, the Trust has no plans to develop this as an access site.


Bibliography

Allen. P. M. and Jackson. A. J. (1985). Geological excursions in the Harlech Dome, Classical areas of British geology. British Geological survey. HMSO. London. Campbell. S. and Bowen, D. Q. (1989). Geological Conservation Review - Quaternary of Wales.


W. A. Wimbledon Editor in Chief. NCC Peterborough. Day. P. (1985). Broad-leaved Woodlands in the North Wales Region. 3 Vols. NCC, Peterborough. Garrett. S. and Richardson, C. (1989). Gwynedd Inventory of Ancient Woodlands (provisional).

NCC. Peterborough.


Hodgetts. N. G. (1992). Guidelines for Selection of Biological SSSIs: Non-Vascular Plants. JNCC. Peterborough.


Linnard. W. (1982). Welsh Woods and Forests: History and Utilization. National Museum of Wales. Cardiff. UK.


Looney. J. H. H. and James. P. W. (1987). Effects of acidification on lichens. Interim report to NCC. Peterborough.


Meteorological Office Commercial Services (1991). A report on the climate of three areas in West Gwynedd. Met. Office.


Specialist Consultancy Group, Bracknell. Ratcliffe. D. A. (1968). An ecological account of Atlantic bryophytes in the British Isles. New Phytologist 67 365.


Ratcliffe. D. A. (ed.)(1977). A Nature Conservation Review. Cambridge University Press. Cambridge.


Roberts R. A. (1959) Ecology of human occupation and land use in Snowdonia. Journal of Ecology, 47 317-323.


Rodwell, J. S. et al. (1991). British Plant Communities. Vol 1. Woodlands and Scrub. Nature

Conservancy Council. Cambridge University Press. Cambridge. Rose, F. (1971). Unpublished report on the Cryptogamic vegetation of woodland areas in North Wales. (Reserve file)


Soil Survey of England and Wales (1983). Sheet 2 Wales. Lawes Agricultural Trust, Rothamsted

Experimental Station, Harpenden.


Stewart. A. Pearman, D. A. and Preston, C. D. (1994) Scarce Plants in Britain. JNCC, Peterborough.


Nature Conservation Features

A full evaluation was not required for this site. This is because the Trust has extremely limited resources for management and has adopted a policy of managing sites to safeguard the main habitats and any legally protected species. There is an assumption, or hope, that all other species will be protected as a consequence of habitat protection.


The site is entirely covered by woodland, and the only protected species is a population of lesser horseshoe bats.


Legally recognised conservation features


1. Broadleaved Woodland:

        W17: Quercus petraea/Betula pubescens/Dicranum majus woodland W17b: Typical sub-community

        W17c: Anthoxanthum odoratum/Agrostis capillaris sub-community


The wooodlands are mainly even-aged stands of mature oak, with little variation in tree age apart from occasional older trees on roadsides, track-sides and in the vicinity of Trawscoed House. There is a concentration of older trees, with some veterans, in the


Cadair Rhys Goch section of the woodlands. These were possibly retained near the house as a landscape feature. The tree canopy is largely complete, but there are some exposed, west-facing areas where a severe gale in October 2(X)2 created a landscape of fallen large trees. Beech is a relatively frequent canopy species, but. with the exception of birch, holly and rowan, other species are very rare. The habitat is almost entirely upland acid oak woodland (NVC W17), containing two separate sub-communities: the dominant is WI7b, the typical sub-community. W17c, the Anthoxanthum odorutumlAgwstis capil-laris sub-community, occurs where soils are deeper and slightly less acidic.


2. Lesser horseshoe bats Rhinolophus hipposideros


Horseshoe bats are easily identified by a horseshoe-shaped flap of skin called a nose-leaf which surrounds the nostrils. This amplifies the ultrasonic calls that the bat emits when searching for food. Lesser horseshoe bats can be distinguished from the greater horseshoe bat by size. These are quite small bats: the body length is around 3.7cm. with a wingspan of 24cm. Individuals weigh between 4 and 9g. Unlike the greater, where the fur has a reddish hue, the lesser has long fluffy fur. pale greyish-brown on the back with a paler grey front.


The lesser horseshoe bat was originally a cave-roosting bat. although most summer maternity colonies now use buildings, particularly large, old houses and farm buildings. Most still hibernate in underground sites such as caves and old mines. Females forage within 2-3 km of the maternity roost, feeding on insects taken in flight in mixed woodland, hedgerows and tree lines.


In Britain, the lesser horseshoe bat is now found only in south-west England and Wales. It was formerly present in south-east England and the Midlands. Current estimates suggest a UK population of 14,000, divided equally between Wales and England. About 230 summer (or all-year) roosts and about 480 hibernation roosts are known. Of the latter, only 20% are used by more than 10 bats. The lesser horseshoe bat is widespread throughout central and southern Europe, but has undergone severe decline in the northern part of its range. (UK Biodiversity action plan)


At the reserve, the lesser horseshoe bats depend on the mosaic of semi-natural habitats and woodland, at and surrounding Trawscoed, for feeding. The valley has a number of known summer breeding and hibernation roosts, and their specific dependence on the reserve is not known. The two largest known lesser horseshoe bat breeding roosts are very close to the reserve, and both have in excess of 300 bats. One is in the upper part of a stable block, immediately adjacent to the reserve, and the other is in a private residence within 0.5 mile of the site. In addition, there are three known underground hibernation roosts in mine workings very close to the reserve.



The key factors which are most likely to influence the features on this site:


The landowner's objectives for the site

Sheep grazing on land surrounding the site, because there is potential for trespass

Rhododendron, mainly offsite, as a source of seed form extensive upwind flowering populations

Past management, both woodland and agriculture

Beech

A tree preservation order (1950)

Aerial pollution and climate change

Human disturbance at the summer breeding roost

The condition of the building at the summer roost

The presence, offsite, of old abandoned mine workings providing hibernation sites for the bats


Action Plan

An action plan is a logical sequence of steps from setting a measurable objective, which is really a vision of what has to be achieved, defining the rationale for removing the barriers, the limiting factors, to acheve the vision through projects and monitoring the outcomes of the projects in relation to the objective.


The 'rationale' first appeared in published form in the UK Nature Conservancy Council's Site Management Plans for Nature Conservation -a working guide (NCC 1988). At this time, the rationale was used to decide how the objectives of management can be achieved, or if necessary modified. Its primary function is to identify the management requirement for each feature. The following list of specific functions was given:


The purpose of the rationale is:


To consider the implications of the current status of a feature.

To identify the factors which are relevant to the feature and ensure that these are monitored or recorded.

To consider how a feature might be influenced by the impact of any significant factors.

To identify the most appropriate management and management options.

To consider the relationships and in particular any conflicts between the different site features.

To identify any factors which may require operational limits.


Objectives

The objective of a conservation plan is a description or vision of the desired state of a system.


Objectives must be quantified so that they may be monitored to reveal how close tmanagement is to achieving them. This requires the definition of a performance indicator. .


A performance indicator for an objective is a measurable attribute of the objective. Its role is to provide evidence that a feature is in a favourable state or condition that was defined in the objective.


A performance indicator may also be defined for a factor to provide evidence that the factor is under managerial control.


Bats


Vision

The woodlands at Trawscoed will contribute towards maintaining a sustainable, robust and viable population of lesser horseshoe bats in the valley. There will be a variety of both hibernation roosts and summer breeding roosts which are available to the bats. All the currently used roosts will continue to be suitable for, and available to, the bats. The maternity roost at Trawscoed will contain at least 250 bats which raise sufficient young to ensure the survival of this population.


The size and range of the population is not restricted or threatened, directly or indirectly, by any human activity. The population within the valley will interact with populations in adjacent areas, thus maintaining a diverse gene pool for the species.


Rationale

.


Current status

The bat population has gradually increased since its discovery in 1997. However, the limit that has been established is provisional. It is therefore not possible at this time to comment on the status of the bat population other than to assume that it is at least recovering. The implications for management are to continue as before: the roost is clearly successful. There is consequently no reason for any changes to management.


Factors


Bats' access to the breeding roost


The following factors are important: Casual disturbance by people at the breeding roost. The bats gain access to the roof space in the workshop by flying through an open window fitted with a shutter. There are no other access routes, but the shutter is ideal: it provides fly-in access without apparently affecting temperatures in the roof space. The shutter must be open from at least 1 April until all the bats have left in the autumn.


Condition of the building


The building housing the bats is in good structural condition, and no maintenance/ remedial work is required in the foreseeable future. Management input will be continued liaison with the owner and tenant of the property to ensure that the reserve manager maintains a good working relationship and is aware of any potential activities or changes which may have implications for the bats. The house and the workshop above the stable in the farmyard complex at Trawscoed which is used by lesser horseshoe bats for breeding was let on a 50-year lease in 1997. The tenants are extremely sympathetic to the bats but need to use the room in which they roost. A false ceiling was erected in March 1998 to prevent the bats from being disturbed by activities in the room below. This seems to have resolved the situation without apparent detriment to the bats. It is difficult to establish meaningful monitoring or surveillance, but, providing a good relationship is maintained with the tenant, the risk to the bats is extremely low.


The woodland habitat


The most significant factor is the woodland, which provides some of the main feeding habitat for the bats. It is assumed that if the woodland is maintained at Favourable Conservation Status this will be adequate to meet the requirements of the bats.

Offsite factors


There are additional offsite factors, but, unfortunately, these are not in the control of the site manager. The most significant factor is potential loss of, or disturbance to, hibernation roosts. Several are known in the valley: they are all in abandoned mine workings, some of which are regularly visited by underground explorers. All have been designated as SSSIs because of their importance to lesser horseshoe bats. This should increase their protection against development. Some mine entrances may also be fitted with lockable grilles to reduce the incidence of casual disturbance. The reserve manager will liaise with the local CCW officer.


There are no obvious factors that can be monitored


Performance indicators

Attributes:


Number of adults in the maternity roost


The only attribute that can be monitored, without any risk of disturbance, is the number of adults in the maternity roost. There may be more than 300 bats present in the stable block at any time during the breeding season. However, given that the roost was only discovered in 1997 and there is no information available prior to this date and the capacity of the roost is unknown, it is not strictly possible to set useful limits for monitoring. Ideally, the population should be kept under surveillance for a longer period to establish both capacity and variations in use. However, managers need a warning system and, consequently, provisional limits will be set and a monitoring project established.


Attribute: Number of adults in maternity roost Upper Limit: Not required


Lower Limit: 250 bats present at any time during the breeding season


Woodland


Vision

The entire site is covered by a high forest, broadleaf woodland. The woodland is naturally regenerating, with plenty of seedlings and saplings particularly in the canopy gaps. There is a changing or dynamic pattern of canopy gaps created naturally by wind throw or as trees die. The woodland has a canopy and shrub layer that includes locally native trees of all ages, with an abundance of standing and fallen dead wood to provide habitat for invertebrates, fungi and other woodland species. The Held and ground layers will be a patchwork of the characteristic vegetation communities, developed in response to local soil conditions. These will include areas dominated by heather, or bilberry, or a mixture of the two, areas dominated by tussocks of wavy hair grass or purple moor-grass, and others dominated by brown bent grass and sweet vernal grass with abundant bluebells. There will also be quite heavily grazed areas of more grassy vegetation. Steep rock faces and boulder sides will be adorned with mosses, liverworts and filmy ferns.


The lichen flora will vary naturally depending upon the chemical properties of the rock and tree trunks within the woodland. Trees with lungwort and associated species will be fairly common, especially on the well-lit woodland margins.


The woodland does not contain any rhododendron or any other invasive alien species with the exception of occasional sycamore. There will be periodic light grazing by sheep. This will help to maintain the ground and field layer vegetation but will not prevent tree regeneration.


An 'inspirational' version of this objective.


'In spring, sunlight sifts through the pale, translucent green of the newly emerged leaves sketching bright patterns between the trees. The upland broadleaved woodland covers the entire site. It has a mixture of trees differing in age, size and density, a variety that is maintained by natural processes. Scattered through it is a patchwork of temporary glades that are slowly filled by naturally regenerating tree seedlings and saplings. At the same time, new openings are created, forming a gradually changing mosaic of light and shade, where as much as a quarter of the woodland may be open glades, rides and other canopy gaps. At certain times of the year, sheep may occasionally wander among the trees and glades as they graze. With so much diversity, a whole web of life, from plants and mammals to birds and insects, is woven through the woodland.


Most of the trees and shrubs are locally native broadleaved species such as sessile or hybrid oak, downy or pendulous birch, ash, rowan, holly, elm and hazel. These, together with occasional non-native species such as beech and sycamore, create patterns of dappled green as the mix of trees changes throughout the woodland. The monotonous, deep green of rhododendron, which has invaded some of the surrounding countryside, does not encroach into the woodland. For life in the woodland to flourish, there must be a balance between decay and new growth; dead and dying trees, as well as live trees with holes, hollows and rotten branches, provide the necessary habitat for a rich variety of mosses, liverworts and fungi, and also for specialised insect species.


The field and ground layers make a brilliant tapestry of colours and textures. Some areas are bright with the vibrant greens and muted purples of heather and bilberry. In others there are soft tussocks of wavy hair grass or purple moor grass. There are also swathes covered mainly by brown bent grass and sweet vernal grass, with occasional drifts of pale indigo bluebells in spring. The dense undergrowth helps to maintain the humidity beneath the canopy, which is essential to the survival of many mosses and liverworts. In rocky areas, or where the soil is thin and acidic, these form deep, green carpets. The mix of lichens in all their bright and subtle shades varies throughout the woodland, depending on the rocks and trees that support them. Particularly around the fringes of the wood, where sunlight seeps through, the tree bark is draped with rippled, silver-green clumps of lungwort.


Birdsong resonates through the wood during the breeding season, and there is a faint rustle of leaves where birds such as pied flycatchers, redstart and wood warblers flit between the branches. As the light fades, bats dart silently through the canopy, barely more than shadows in the twilight, and badgers emerge to forage in the growing darkness'.


Rationale


Current status

Gap creation rate within the existing wooded area has been low for many years. However, the gale of October 2002 created many new gaps. The consequence is that the canopy is now much more open and the cover is now between 90% and 75%. This will not be confirmed until aerial photographs are taken. The sudden increase in gap creation rate may not be representative of the general trend in the woods: it is far too early to come to any useful conclusion. For now, with the exception of beech control (see below), there will be no artificial gap creation. However, this option will be kept open for the future in case natural processes and beech removal fail to produce sufficient gaps. The new gaps, all containing fallen dead and living trees, will certainly make a significant contribution to the structure of the woodland. In many of the gaps, there is natural regrowth of damaged trees and saplings appear to be surviving. There is now limited natural regeneration throughout the site as a consequence of sheep exclusion in 2002. The overall age structure is varied but comprises a mosaic of even-aged areas which are a reflection of past felling areas. There are no areas with a natural mixed-age structure, and there are very few large, old and derelict veteran trees. The volume of dead wood remains below the specified limits, but since the gale there has been a significant increase. With the exception of the trees which blocked the roads, all other wind-throw trees have been left in place.


Rhododendron is under control: it is now virtually absent throughout the reserve. Unfortunately, the threat of further infestation remains because of the proximity upwind of extensive areas of flowering bushes. This factor remains a threat. Beech is currently estimated at 10%: this is well above the acceptable limits.


Sheep are under control, and this can be maintained. Management can do little to mitigate the effects of atmospheric pollution, which will tend to acidify the already extremely acidic substrates and soils that have no buffering. The effect on long-term tree health is not understood. Stressed trees may become more liable to normal pathogens. Mycorhizae are suppressed by acidification, and lack of them will impair the trees' ability to extract nutrients from the soil. However, there is currently no evidence that the woodland is being adversely affected by atmospheric pollution or acidification.

Current conservation status


The conclusion is that, although there has been an obvious and very significant improvement, the overall condition remains unfavourable. The indication, based on an assessment of the factors, is that recovery will continue. The status is, therefore, recovering.


The implication of this status is that the general approach to management will be maintained. Efforts will be directed towards reducing the potential for further invasion by rhododendron and ensuring that the rhododendron-monitoring project is maintained. The main management activities will be liaison and participation in a partnership with the National Park, the National Trust and local land owners to control rhododendron over the wider area.


A programme to accelerate the removal of beech will be developed. A Tree Preservation Order was placed on most of the site and some surrounding woodland areas in 1950. Overall, this has a positive impact, but given that controlling beech will involve felling quite large trees permission will be required. The selective removal of beech will be managed to provide canopy gaps suitable for regeneration.


There will be no further removal of dead wood, even if footpaths have to be re-routed.

The stockproof fences will be maintained in good condition, and any trespassing sheep will be removed as soon as possible.


The Countryside Council for Wales will be contacted for advice on atmospheric pollution and climate change.


Note: the most significant factors and the implications for management have been dealt with in the preceding assessment of status. The following two additional factors are included because they help to account for the current condition of the woodland.


Owners'/occupiers' objectives


The entire site is owned by a private owner whose objectives are similar to those of the Trust. There are no conflicts of interest.


Past woodland management


The entire woodland area has been managed in the past as productive high forest, producing timber for construction, ship building, firewood, tanbark, etc. There is no apparent evidence of coppice management in the present stand of trees. The consequence of past management is that the stand of trees throughout the woodlands is even aged and relatively uniform. Overmature trees are rare, and tree canopy cover is variable. There is very little dead wood, either on the ground or within living trees, throughout the woodlands, except in the most inaccessible locations or in areas affected by the wind-throw episode in October 2002.


Factors

Grazing by sheep


Until completion of the woodland boundary fencing in 2002. sheep grazed freely throughout the woodlands, which were open to adjacent fields. There was very little unprotected recent natural tree regeneration within the woodland. Sheep grazing suppressed the development of structure in the field layer and also prevented the desirable build up of leaf litter. The woodland vegetation was predominantly of well-developed bryophytes with little else. Following grazing control, birch, holly and, to a lesser extent, oak have begun to regenerate naturally.


It is not possible or desirable to completely exclude sheep: there will always be some low-level grazing. In the short term, grazing will be excluded to ensure a period of natural regeneration. An upper limit of one sheep per hectare is acceptable as this will have no significant impact on the woodland.


Alien species: Rhododendron Rhododendron ponticum


Rhododendron is well established in the surrounding area and in the past had infested significant areas of the site. This was cleared in 1995 and the regrowth was sprayed with herbicide in 1996. However, there is always potential for further infestation. The clear aim of management is to eradicate the species from the site. The problem is that it is very difficult, and probably impossible, to prove that there is no rhododendron in an area. The seedlings are extremely small for the first few years and even when rhododendron reaches the sapling stage it is very difficult to locate, particularly when growing in dense woodland. Once the plants begin to flower they can be seen easily, because the pink flowers stand out against the green of the woodland. Monitoring is then very simple: unskilled individuals can wander through the wood searching for flowers, and when they are found all the rhododendron, flowering and non-flowering, can be controlled. If this process is maintained, eventually the species will be eradicated.


Beech regeneration


Beech occurs throughout the site. Many of the trees appear to be younger than the adjacent oak trees. Due to a prolonged period of heavy grazing, beech has not successfully regenerated, but, following the removal of sheep in 2002, this situation may change. Beech is shade tolerant and able to regenerate under a dense oak canopy. It can also produce, albeit very occasionally, a heavy crop of viable mast. There is, therefore, potential for beech to become the dominant canopy species, and the consequential loss of species diversity would not be acceptable. To ensure that this does not happen, the amount of beech in the canopy will be restricted to a manageable level. Although it would be desirable to eradicate beech completely, there would be considerable practical difficulties in achieving this.


Natural regeneration in oak woodlands is only possible when there is enough light for the seedlings and saplings. Woodland that contains a dynamic, changing pattern of gaps will also, over time, deliver a structurally diverse canopy which will provide opportunities for a wide range of associated species. There is, therefore, a need to ensure that there are sufficient gaps in the canopy to provide opportunities for regeneration and that the gaps fill with the required canopy species. Three different attributes will be monitored to provide the evidence that this is actually happening: First, the overall canopy cover is defined; that is, how much of the canopy should be open at any given time. The rate at which gaps should be created is specified. Finally, the presence of viable saplings in the gaps will be monitored. The presence of saplings will indicate that conditions are right for regeneration long before the fact that a gap is filling can be measured.


Canopy species composition


For many obvious reasons, and in particular a need to optimise opportunities for the widest possible range of locally native species, it is essential that the canopy comprises locally native species. There is no tolerance, in the longer term, of beech or any other exotic species.


Dead wood


Dead wood is included as an attribute because it is an extremely useful surrogate, i.e. the presence of dead wood will indicate potential for the presence of a wide range of typical woodland species, including beetles, fungi, epiphytic lichens and hole-nesting birds (Peterken 1993). Dead wood is also a good measure of the ecological structure of a woodland: the presence of too little or too much dead wood will be indicative of a dysfunctional or inappropriately managed woodland. A reasonable and attainable level would be about 30m7ha. Dead wood should consist of a mixture of fallen trees (minimum 1 of girth > 40cm dbh/ha), fallen branches, dead branches on live trees, rot columns in living trees and standing dead trees (minimum 1 of girth > 40cm dbh/ha).


Performance indicators


Factor 1: Sheep


Upper limit: No more than one sheep per hectare in any woodland enclosure Lower limit: No less than 0.25 sheep per hectare



Factor 2: Rhododendron


Upper limit: No flowering Rhododendron

Lower limit: Not required



Factor 3: Beech


Upper limit: 5% in the canopy

Lower limit: None


Attribute 1 Extent and distribution

The current extent of the woodland is 67 ha. This should not decline.


Upper Limit: Not required

Lower Limit: 67 ha


Attribute 3: Canopy cover

Upper Limit: Tree canopy 90% of woodland area

Lower Limit: Tree canopy 75% of woodland area


Attribute 4 The canopy gap creation rate

The canopy gap creation ratewithin the woodland area should be between 0.25% and 0.5% of canopy cover per annum, measured over a minimum 20-year period. (A gap is any area equal or greater than 1.5 times the height of the tallest adjacent tree, or any area of between 20 and 50 m distance across, not including areas of bare rock, etc.)


Upper Limit: 0.5% per annum measured over a minimum 20-year period

Lower Limit: 0.25% per annum measured over a minimum 20-year period


Attribute 5: Natural regeneration within gaps


Upper Limit: Not required

Lower Limit: 2 viable saplings per 0.1 ha of gap

(Where viable saplings are taken to be healthy/ vigorous native tree saplings reaching a minimum height of 1.5 m, consisting of species that will replenish the canopy)



Factor 6 : Canopy species composition


Attribute: Canopy species composition Upper Limit: 100% locally native species Lower Limit: 95% locally native species


Factor: Dead wood


Attribute: Dead wood

Dead wood is included as an attribute because it is an extremely useful surrogate, i.e. the presence of dead wood will indicate potential for the presence of a wide range of typical woodland species, including beetles, fungi, epiphytic lichens and hole-nesting birds (Peterken 1993). Dead wood is also a good measure of the ecological structure of a woodland: the presence of too little or too much dead wood will be indicative of a dysfunctional or inappropriately managed woodland. A reasonable and attainable level would be about 30m7ha. Dead wood should consist of a mixture of fallen trees (minimum 1 of girth > 40cm dbh/ha), fallen branches, dead branches on live trees, rot columns in living trees and standing dead trees (minimum 1 of girth > 40cm dbh/ha).


Upper Limit: Not required Lower Limit: 30 cubic metres/ha


Projects


Bats


Monitoring attribute

Attribute: Breeding roost numbers of adults


RA03/1 Collect data, mammals, monitor - monitor lesser horseshoe breeding roost numbers.


Attribute


Management

Maintain condition of the breeding roost ML00/8 Liaise, owners/occupiers - site owner MLOO/3 Liaise, owners/occupiers - site occupier


Woodland


Management


Rhododendron

ML30/2 Liaise, neighbours - rhododendron control on adjacent land


ML40/1 Liaise local national authorities - rhododendron control on adjacent land


ML50/1 Liaise local community/groups - National Trust rhododendron control on adjacent land


MSOO/OI Manage species, tree/shrub - rhododendron control on site


Purpose: to arrest the spread of rhododendron on the site as quickly as possible, with the target of complete eradication from the site and adjacent land to prevent the threat it poses to the woodland.


General Background:

Rhododendron ponticum is a shrub that was first introduced to Britain in 1763. It is now naturalised throughout Britain in a variety of habitats. Because the inherent strategy of the plant is to form an impenetrable thicket with a dense canopy, thus displacing all other competition, it has become a major ecological and economic problem in native woodlands and in commercial forest plantations. In some areas of Britain it has become a major threat to the survival of native woodlands and woodland species.


Cross (1975) has written a masterful account of the biology and ecology of the species.

Rhododendron ponticum generally prefers an acid soil, tolerates a wide range of temperatures, and occurs at altitudes of up to 530m in the British Isles. Bushes can reach up to 7 or 8 m in height in woodland and up to 5 m in open habitats. Once established, rhododendron is a remarkably hardy plant. It responds to cutting or burning by producing a proliferation of shoots from dormant basal buds, which grow rapidly. Its branches, which are often procumbent, root into the soil when they touch it and produce an independent clone. Its waxy leaf cuticle provides it with remarkable resistance to herbicides, and its foliage is avoided by livestock because it is highly poisonous. The plant is extremely shade tolerant and there is evidence that it can chemically suppress the growth of surrounding plants (allelopathy). It flowers profusely under various (and very low) light conditions, and produces viable seed every year. Calculations made by Cross (1975) showed that each raceme (group of flowers) can produce up to 5,000 seeds. It is not unusual for large, open-grown bushes to have up to 250 racemes, and so may produce over 1 million seeds every year. The seeds are tiny (20,000/g) and are adapted for wind dispersal. They may travel some distance in woodland, possibly up to 1 km, but flowering bushes in exposed, high-altitude locations may be carried much further by wind and turbulence.

Once rhododendron seedlings are established, they grow slowly for the first few years but speed up after about 7 years, lose apical dominance and begin to develop many stems and become bushy. According to the literature, flowering occurs about 12 years after germination, or about 7 years after cutting a mature bush, but direct experience has shown the latter may be as little as 3 years. Shaw (1984) raises the question of where rhododendron colonisation will stop and concludes that, apart from altitude (530m in Britain), there is no obvious limit, particularly in the acidic west of the country. Although its spread is now not thought to be exponential, rhododendron is still insidiously spreading gradually from local and obvious seed sources (Thompson et al. 1992), and, in view of the threats posed to habitats and species, the case for its control could not be stronger.


Issues affecting the control of rhododendron


Strengths (properties that make it a difficult species to control):

It has a strong coppicing ability and regrows vigorously after cutting. The resulting regrowth, left unchecked, is even more difficult to cut within 4 years.

The leaves are covered by a wax layer which is extremely effective at protecting the plant against aqueous herbicide as water simply runs off.

It has the seeding strategy of a weed. It produces millions of very small, light seeds.

It forms dense, impenetrable stands - an excellent survival strategy.

It has few natural predators in this country and it appears to be disease free.

It is a long-lived species (500 years plus in eastern Turkey).

It is extremely shade tolerant at all stages of growth (compensation point is at 2% of full daylight), and, as an evergreen, is active in winter when light levels in woodland are higher.

Its vascular tissue is arranged in such a way that one stem is connected to one part of the root, and any stem missed during application of a systemic herbicide will not be killed, even if the rest of the plant dies.

Weaknesses:

Seedlings/young bushes (even quite large ones) can be easily uprooted prior to multi-stem growth. However, uprooted bushes can survive and eventually re-root unless most soil is removed from the roots and the plant is hung up to allow the roots to dry out.

Reinvasion requires a nearby seed source.


Methodology


Rhododendron is cut and later the regrowth is treated with herbicide. Small bushes or saplings can be simply uprooted and hung up to dry. Cutting is best carried out during winter to avoid disturbance to wildlife and to avoid risk of missing the bushes that are hidden by bracken or other vegetation.


Beech

MS00/2 Manage species, tree/shrub - control beech ML40/02 Liaise local national authorities


Gap creation


MH02/I Manage habitat, woodland/scrub, by thinning/group felling - silvicultural management/canopy gap creation


Sheep grazing

RA04/1 Collect data, mammals, count/estimate/measure/census - woodland sheep

grazing by observation


MLOO/3 Liaise, owners/occupiers - liaise with graziers


ME01/1 Boundary structures - inspect/maintain boundary structures - TPO consent


Purpose: To maintain an ongoing awareness of levels of sheep trespass in the woodland areas and to ensure removal of sheep once numbers exceed 8 in any enclosure. (Note: light sheep grazing in a wood may be beneficial in removing competition for oak seedlings, but regular, heavy sheep grazing will cause damage to natural tree regeneration.)


General Background: The woodlands have been heavily grazed by sheep for a very long period before the reserve was established. Between 2000 and 2002 the woodlands were fenced to exclude stock.


Methodology: Walk through all woodland areas regularly, at least once a month, to check for sheep trespass. Cover all areas visually and record the number of sheep seen. If sheep are inside an enclosure, attempt to locate how they got in and arrange for the repair of any damage to fences/ walls etc. If there are more than 8 sheep in any enclosure, take action to evict them as soon as possible.


Specific Risk Assessment: See SHI/SHA for Trawscoed.


Reporting Requirement:

Annual summary will be maintained in CMS.


Project Diary


Thursday, 13 December 2012


Monitoring attributes


Factor: Sheep

RA04/I Collect data, mammals, count/estimate/measure/census - woodland sheep grazing by observation (note: this project is described below).


Factor: Rhododendron

RF14/2 Collect data, trees/shrubs, count/estimate/measure/census -sweep site for rhododendron


Factor: Beech

RF03/4 Collect data, vegetation, monitor - monitor beech


Objective: Extent of Woodland

RF13/5 Collect data, trees/shrubs, monitor - monitor extent of woodland area


Objective: Canopy cover

RF13/6 Collect data, trees/shrubs, monitor - monitor extent of woodland canopy


Objective: Canopy Gap Creation

RF13/8 Collect data, trees/shrubs, monitor - monitor gap creation rate


General background/bibliography:


The use of aerial photography to monitor gap creation rate has been developed on this site.


Methodology: The method is very simple. It involves the identification of new gaps in the woodland canopy from aerial photographs. This is followed by a visit to each gap where the actual extent is measured. When the total area of gaps within a defined sample area is known, this can be compared with previous results, and the rate of gap creation can be calculated.


(a) Equipment: A site map

The aerial photographs Computer with GIS

(b) Location of sample collection: the sample areas are marked on the project map.

(c) Fixed point markers: none

(d) Sampling technique: the woodland area is divided into a series of roughly equal-sized blocks (the actual shape is not important). These divisions will enable the comparison between successive photographs and, most importantly, they can be located on the ground.


Initially, all the canopy gaps are numbered and delineated on the aerial photograph by carefully drawing a fine line around the inside of the edge of the canopy. (A gap is any open area equal to, or greater than, 1.5 times the height of the tallest adjacent tree, or any area of between 20 m and 50 m distance across, but not including areas of bare rock. Open areas which appear smaller than the crown spread of the largest immediately adjacent tree are ignored.) Occasionally, a best estimate will have to be made due to the presence of shadows at the glade edges. The GIS workspace is saved to provide the information for future comparison.


On subsequent occasions this procedure is repeated, and the new gaps or extensions to older gaps are delineated.


A print of the digitised aerial photograph is taken on a field visit and used to locate, on the ground, all the new gaps within the sample areas. Ensure that each gap fits the definition given above, and ignore any that do not. Estimate the area of each by pacing or measuring the edge of the gap. The edge of the gap is defined by the edge of the canopy (imagine a perpendicular projection of the canopy on to the ground, i.e. the edge of the shadow when the sun is vertically overhead). Within each sample area, work out the total area of the new canopy gap.


The next stage is to calculate the gap creation rate. G is the area of new gaps since the last photograph. A is the size of the sample area. T is the number of years between successive photographs.


The Gap creation rate expressed as a percentage of the total area = (G/A)/T x 100.


For example, new gaps (G) is 1 ha, the sample area (A) is 20 ha and the time between photographs (T) is 10 years. The gap creation rate is (l/20)/10 x 100 =

0.        05.10 x 100 = 0.5% per annum.


(e) Unit of measurement: the number of canopy gaps, the area of individual gaps in hectares, the rate of gap creation for sample areas as an annual percentage.

(0 Sampling period: any time when the canopy is in leaf (May-October).

(g) Frequency of sampling during sampling period: Once every 12 years unless there are significant events, for example, severe wind-throw.


Risk assessment:

This is a very low-risk, indoor-based project. The general site risk assessment will be applied during the field work component.


Objective: Regeneration

RF13/7 Collect data, trees/shrubs, monitor - monitor tree regeneration


Objective: Canopy composition

RF13/11 Collect data, trees/shrubs, monitor - monitor tree canopy composition


Objective: Dead wood

RF13/10 Collect data, trees/shrubs, monitor - estimate volume of dead wood