|
|
Home
>
2. Sites: 1977
>
2.2 Wales
|
Previous
Next 
|
|
|
|
|
|
|
|
|
|
|
|
|
|
W.gS. BLAENAU NEDD &
MELLTE, BRECKNOCK
SN 9210.
60 ha
Grade 2
These woodlands are situated
in the upper gorges of the Neath River
to the north of the South Wales coalfield, and within the Brecon
Beacons National Park. Outcrops of Carboniferous Limestone occur
only on the higher parts of the gorge sides and its influence is
localised; the river itself cuts through Millstone Grit. The
composition of the woodland in these gorges varies from a grazed
acidophilous sessile facies; through a more mixed deciduous type
with ash, wych elm and a little small-leaved lime in the canopy with
hazel, field maple and some hawthorn below; to the stream sides
dominated by birch and alder. Small areas of mesophilous vegetation
occur, though, in the main, a grazed acidophilous field layer is
present. Deschampsia flexuosa is the main constituent with a ground
layer of Dicranum majus, Leucobryum glaucum, Polytrichumformosum,
Mnium hornum and Diplophyllum albicans. Luzula sylvatica and
Vaccinium myrtillus are only present on inaccessible rock outcrops.
The splash areas of the waterfalls and trees and rocks in the gorges
have ferns and bryophytes, rare or local in south Wales, including
Hymenophyllum tunbrigense, H. wilsonii, Ptilidium pulcherrimum and
Isopterygium pulchellum. |
|
W-97- CARN
GAFALLT, BRECKNOCK
SN 9464.
no ha
Grade 2
This complex of woodlands
lies south of Rhayader on the slopes of
Silurian rocks above the rivers Elan and Wye. A discontinuous belt
of oakwood lies around the north-west, west and south flanks of the
hill, Carn Gafallt. The slopes above Elan village are block strewn,
the rock being a hard grit compared to the slates nearby. Variation
in form and size of the trees, due to past management, occurs
throughout. Here the oaks, though short, are spreading and of good
girth. Bryophyte communities are well developed on the blocks,
particularly Scapania gracilis with Lepidozia pinnata, and other
western species present include Bazzania trilobata. Bilberry is
dominant locally but in places there are dense, pure carpets of
moss. A small area of large oak (up to 21 m) with a more uniform
field layer, dominated by bracken, lies to the west of a nearby
stream. The remainder of the woods towards the south also contain
oak of medium size with moss or bilberry-dominated communities.
A woodland with an intimate
mixture of sites and species lies on
gentler slopes to the south side of the Dulas stream, where the rock
is richer in bases and numerous flushes occur. Patches are dominated
by oak, ash, alder or birch or by a mixture of all four species.
Wych elm is scattered throughout, hazel and hawthorn are plentiful,
and rowan and holly are also present. Parts of the wood have a block-
strewn
floor and elsewhere a rich field layer on mull soils passes
in places to flush mire under alderwood.
Some of the woodlands in
this complex are perhaps as good as
existing Reserves but since they duplicate the interest of these and
there are no unusual associated features, a status higher than grade
2 is not considered to be justified. (See Appendix.)
The valley bottom has old
pastures and hay meadows (with Sanguisorba
offidnalis abundant, Carex hostiana, Equisetum sylvaticum,
Platanthera chlorantha, Vicia cracca and V. orobus locally common),
Juncus marsh (with Eleo-charispalustris, Scutellaria galericulata,
Sparganiumramosum and Triglochin palustris) and wet heathy fields
with some developing Sphagnum bog (with Vaccinium oxycoccus, Drosera
rotundifolia, Wahlenbergia hederacea and in drier parts Genista
anglica, G. tinctoria and Cirsium dissectum). |
|
W.88. CWM
CLYDACH, BRECKNOCK SO 2112. 2O ha
Grade i
This reserve, which is
within the Brecon Beacons National Park,
consists of two blocks of woodland, the upper Coed Fedw-ddu and Coed
Ffyddlwn, both on the south side of the Afon Clydach ravine. The
underlying Millstone Grit and Carboniferous Limestone provide both
acidic and base-rich conditions. The soils are shallow, stony and
boulder strewn, and podsols only lie on the gentler slopes. Litter
up to 50 cm has been recorded and it decomposes rapidly, partly
because of the extreme dampness at the bottom of the valley which
rarely receives any sun.
Beech is dominant in the
canopy throughout, and on the shallower
well drained soils sessile oak is a co-dominant with birch. Rowan,
hawthorn, hazel, blackthorn and Salix atrocinerea are in the shrub
layer.
Where the soil is wet with
a deeper clay overlying limestone, wych
elm is co-dominant with ash, and yew, holly, elder, as well as
hazel, are in the understorey. There is a range passing through pure
beechwood between these two woodland types. The poor, acidic soils
characteristically have a herb layer dominated by Deschampsia
flexuosa, accompanied by species including Blechnum spicant,
Dryopteris borreri, Luzula sylvatica and Athyrium filix-femina with
locally frequent Vaccinium myrtillus and Pteri-dium aquilinum. Where
the soil is neutral, base-rich and poorly drained, Deschampsia
cespitosa dominates the herb layer in association with Brachypodium
sylvaticum, Epi-lobium montanum, Mercurialis perennis, Mycelis
muralis, Phyllitis scolopendrium, Polystichum setiferum and P.
lobatum. Allium ursinum is locally abundant. Accumulations of
Sphagnum spp. and Leucobryum glaucum also occur.
Hawthorn scrub and a mixed
scrub community occur on the margins and
river flushes; stream-bank communities and limestone outcrops with
yew add to the variety of habitats within the reserve boundary.
The trees are not markedly
even-aged and regeneration appears to be
successful. Although it has been recorded growing elsewhere in the
locality associated with the Carboniferous Limestone, Cwm Clydach
appears to be the largest and therefore the best representative area
of native beech on the western fringe of its natural distribution in
Britain. |
|
W-99- DARKEN FACH,
BRECKNOCK
so oiio.
12 ha
Grade 2
This west-facing site lies
across the upper Taff valley, a short
distance upstream from Penmoelallt, and can be considered an
alternative to it. It consists of an open scrub on low limestone
cliffs with screes and woodland on the gentler slopes. The latter
are dominated by ash inter-mixed with wych elm together with a well-
developed understorey of hazel and hawthorn. Field maple is present
and a group of small-leaved lime lies at the northern end. The
primary interest lies in a concentration of Sorbus spp. on the
southern end of the Barren Fach crags. Several shrubs of S. leyana
together with a specimen of S. porrigentiformis grow just below the
crags together with ash, yew and holly.
The ground layer is heavily
grazed and includes Mer-curialis
perennis, Oxalis acetosella, Rubus fruticosus agg.,
Deschampsia cespitosa,
Phyllitis scolopendrium with some Asperula
odorata. |
|
W-96. NANT
IRFON, BRECKNOCK
SN 8454.
40 ha
Grade 2
The Irfon valley is narrow
and steep-sided with extensive outcrops
of Silurian rocks. Two blocks of north-east-facing, hanging sessile
oakwoods spanning an altitude of 290-380 m lie within the boundary
of the NNR. Their primary interest is the presence of breeding
raptors. The site includes woodland on the opposite side of the
valley.
Coed Ty-mawr is a steep
compact area of almost pure, uncoppiced
sessile oakwood. Apart from the northern,
exposed section the trees
are well developed and open grown. It has
a wet oakwood field layer with a rich and varied bryophyte flora,
from Polytrichum and Hypnum species on dry sites through Thuidium
tamariscinum and Dicranella heteromalla, to Sphagnum palustre, S.
papillosum and Fissidens taxifolius on wet sites. Coedydd Hen-Nant &
Digydd is an extended and discontinuous woodland intersected by deep
cwms and is variable in breadth and density. It is predominantly
sessile oak, open, uncoppiced and with well-developed crowns, with
some downy birch, rowan, hazel and ash. Hawthorn and occasional
beech are present. The lush ground cover is similar to Ty-mawr but
there are patches of Pteridium aquilinum or of Agrostis tennis and
other grasses. Wet boggy flushes have Molinia caerulea, Sphagnum
spp., and Carex spp. and there are bryophyte-covered wet, shady
screes.
Coedydd Bron-gynes &
Clawdd-coch lie outside the present Reserve.
These are comparatively dry woodlands on shallow soils facing west-
south-west. They form a low bank intersected by a few shallow cwms.
Coppiced sessile oak is dominant with occasional downy birch and
rowan. The ground flora is variable though grazed. Bracken is
dominant in the more open areas and in other sections mosses,
including Hypnum cupressiforme var. ericetorum, Hylocomium
splendens, Rhytidiadelphus squarrosus, Polytrichum commune, P.
formosum, Mnium hornum and Atrichum undulatum, are most abundant.
The higher levels are grassy with Agrostis tenuis and Anthoxanthum
odoratum. Rock outcrops bear Calluna vulgaris with Festuca ovina and
Polytrichum piliferum.
See also U.g. |
|
W.Sg. PENMOELALLT,
BRECKNOCK
so 0109.
7 ha
Grade i
This Forest Nature Reserve
comprises a small strip of mixed
deciduous woodland owned by the Forestry Commission overlying a
narrow Carboniferous Limestone belt which forms a low escarpment.
The major interest is the presence of three well-developed specimens
of Sorbus leyana, endemic here, and the abundance of S.
porrigentiformis. However, the Reserve bears a type of woodland now
rare in Wales. On the limestone scree the tree cover is dominated by
ash together with wych elm and rowan. The ground flora has much
Mercurialis perennis, Geranium lucidum and
Asperula odorata, and calcicolous
bryophytes are well represented on
the rocks.
On deep clay soil towards
the southern end of the woodland the tree
cover is mixed and is dominated by pedunculate oak together with
ash, elm, rowan and silver birch. Small-leaved lime is also present
and hazel is frequent in the shrub layer. Abundant species of the
ground flora are Endymion non-scriptus, Oxalis acetosella, Viola
riviniana and V. reichenbachiana. |
|
|
|
|
W.QO. COED RHEIDOL, CARDIGANSHIRE
SN 7478.
75 ha
Grade i
The Rheidol valley sides
are covered in mainly oak woodland over
much of their length, with the best stands immediately above and
below the Rheidol Falls. At Devil's Bridge there is a confluence of
twin streams which have cut deeply through Silurian sediments to
form deep gorges clothed for the most part in even-aged sessile oak
woodland with some birch and rowan. Beneath this on the acidic brown
earth and podsol soils, the field layer is strongly calcifuge in
character, i.e. of Vaccinium myrtillus, Molinia caerulea,
Deschampsia flexuosa and Melampyrum pratense, with a strong
bryophyte component, e.g. Dicranum majus, Leucobryum glaucum and
Eazzania trilobata, reflecting the high humidity in the ravine.
Locally in the acidophilous woods birch is dominant, but the main
variation is produced by river- and streamside flushing. Here mixed
deciduous woodland of sessile oak, ash, wych elm and hazel with rare
small-leaved lime has developed with a basiphilous ground flora of
Circaea lutetiana, Sanicula europaea, and ferns. A number of
Atlantic bryophytes are present, Jamesoniella autumnalis, Radula
aquilegia, Marchesinia mackaii, Cepha- loziella pearsonii,
Harpakjeunea ovata, Scapania gracilis, Jubula hutchinsiae, Saccogyna
viticulosa, Lepidozia pinnata and L. pearsonii, and some local
vascular plants, including Trollius europaeus, Festuca altissima,
Meconopsis cambrica, Hymenophyllum tunbrigense, Asplenium
septentrionale and Dryopteris aemula. The site extends below the
Rheidol Falls to the western end of Allt Ddu where on either side of
a tributary stream in sessile oak coppice woodland, ranging in age
up to 150 years, there is a fine example of contrasting ground flora
types on broadly east- and west-facing slopes. |
|
|
|
|
W.I04- COEDYDD ABER, CAERNARVONSHIRE
SH 6671.
165 ha
Grade i
These woods form a somewhat
dissected complex along the valley of
Afon Aber, and contain at least four distinct types. In altitude
they range from 30 to 210 m, and at the north end of the valley
rainfall is only 114 cm annually. The parent rocks are Ordovician
and Cambrian grits and shales, and the lower slopes are drift
covered. The woods on the upper parts of the system on both east and
west sides have typical dry oakwood of sessile oak with some birch
and rowan on acidic skeletal brown earths, but these grade below
into mixed deciduous woodland of ash, wych elm, oak, birch and
abundant hazel on base-rich clayey soils, on both steep slopes
bounding a central ravine and flatter ground to the north and south.
The oakwood has a typically
acidophilous field layer with Agrostis-
Anthoxanthum grassland, a good deal of bracken locally, and a well-
developed moss layer in which Atlantic species are not particularly
well represented, probably because there are few blocks and also
because of unfavourable management. The mixed woodland has the
richer Brachypodium sylvaticum herb-rich grassland, with an
abundance of basiphilous species. On the steep slopes flanking the
ravine, the fern Polystichum setiferum is abundant, while the rock
ledges have a fine colony of the very local grass Festuca altissima,
and Hypericum androsaemum also grows here.
On flatter, waterlogged
ground there are patches of alderwood with a
swampy floor containing fairly hydrophilous species such as
Ranunculus repens and Chrysosplenium oppositifolium. Where the wood
thins out at the head of the valley, there is a transition to a
fairly extensive area of open hawthorn scrub with some crab apple in
a grassland community containing a great abundance of bluebell. This
passes into the precipitous northern cliffs down which pour the Aber
Falls, and the lower and more broken faces here have interesting
examples of ungrazed cliff woodland with stunted oak, birch and
rowan, and a luxuriant field layer of Luzula sylvatica (illustrating
the sensitivity of this species to grazing). Atlantic bryophytes are
well represented on these cliffs near the falls and include very
local species such as Adelanthus decipiens, Anastrepta orcadensis,
Eazzania tricrenata and Hylocomium umbratum.
The lichen epiphyte flora
is one of the most interesting in north
Wales. It is essentially lowland in character, consisting of a rich
Lobarion community in the ravine with Parmeliella plumbea in its
only certain recent north Welsh locality in local abundance. Great
rarities here are Arthonia cinere-opruinosa (four British
localities), on an old dry bank, Polyblastia allobata, Gyalidiopsis
sp. (undescribed and new to science) and Mycoblastus fuscatus.
Perhaps the most important
feature of Coedydd Aber is the diversity
of woodland types within a single complex, reflecting differences in
soil conditions and management. The site is contiguous with the
Carneddau part of the Eryri upland site (U.io), and can be regarded
as a habitat extension of the latter. Coedydd Aber also has a
particularly varied bird fauna, with strong breeding populations of
wood warbler, pied flycatcher and redstart. |
|
W.IIO. BRYN
MAELGWYN & GLODDAETH,
CAERNARVONSHIRE SH 8o8l.
80 ha
Grade 2
This is one of a group
of similar woodlands on Carboniferous
Limestone close to Llandudno. It is high forest of ash, wych elm and
oak, with some sycamore and yew, and a shrub layer with privet,
hazel and hawthorn, over a calcicolous ground flora with
Brachypodium sylvaticum and Mercurialis perennis dominant. The
woodland grades through scrub of hawthorn, clematis, privet,
blackthorn and bramble to limestone grassland containing the rare
Veronica spicata ssp. hybrida.
Other woods in the group
are Pydew Pabo, Caernarvonshire, and Bryn
Euryn, Denbighshire. Whilst Pydew Pabo is regarded as marginally the
best woodland in the group, Bryn Maelgwyn is chosen because it is
adjacent to and grades into rich limestone grassland. |
|
W.IO6. COED
DINORWIG, CAERNARVONSHIRE
SH 5860.
50 ha
Grade i
This wood is unusual in
being an ungrazed upland sessile oakwood;
fenced off from sheep by the farms above and the Dinorwig quarries
to the south-east. The oaks are mostly rather small and many are
grown over with ivy; there is a patchy underscrub of hazel and
holly. The field communities are the most interesting feature, with
dominance of Luzula sylvatica in the upper part, and a good deal of
bilberry and bramble elsewhere. Field communities of this kind are
characteristic of ungrazed hill woods on acidic to mildly basic
soils, and are well represented in the oakwoods of the Loch Lomond
islands (W.i69), and some ravine woods. They are, however, rare in
the hill woods of Wales. There are block screes and rock outcrops
with some Atlantic plants, including Hymenophyllum wilsonii, Plagio-
chila spinulosa and Scapania gracilis. At the upper fringe, the wood
grades into tall Callunetum on rocky bluffs, and there is a
transition zone with small, stunted oaks, which are almost certainly
the result of coppicing or other human disturbance. |
|
W.IO3- COEDYDD DYFFRYN
CONWY, CAERNARVONSHIRE
(a) Coed Dolgarrog SH 7666.
70 ha
Grade i
This wood extends for about
1.6 km along the steep western side of
the Dyffryn Conwy and is bounded to the north and south by deep
rocky ravines formed by streams whose flow is now somewhat reduced
by the Dolgarrog Hydro-electric Scheme. The wood has a large
altitudinal range from 30 m to over 300 m but, apart from the upper
margin, is sheltered from the prevailing south-west winds. Rainfall
is about 150 cm annually, but humidity is lower than in the
adjoining gorge woodlands, such as Ceunant Dulyn. The rocks are
Ordovician rhyolites and rhyolite tuffs in the south, followed in a
northerly direction by a massive buttress of pumice tuff projecting
into the main valley, then a concave slope of slate and finally, in
the extreme north, a second but smaller buttress of pumice tuff. The
pumice tuff yields soils of moderate base-status, as in Ceunant
Dulyn, whilst the other rocks yield more acid soils. The underlying
rocks are often masked by layers or pockets of drift particularly on
the upper slopes and mixed colluvium on the lower slopes.
The dominant tree is oak,
of both species as well as hybrids, though
in contrast to Coed Gorswen there is a preponderance of sessile
types; there is no marked association here between soil type and
species of oak. However, this wood is best included in the mixed
deciduous category, for there are numerous other tree species,
either as scattered individuals or locally dominant. They include
birch, wych elm, ash, alder, sycamore, rowan, holly, small-leaved
lime and crab apple. Beech is occasional throughout the wood and a
few conifers, Scots pine, Norway spruce and larch, are also present.
On the more base-rich soils the flora is characterised by such
species as Brachypodium sylvaticum, Mercurialis perennis, Circaea
lutetiana, Sanicula europaea, Fragaria vesca, Allium ursinum,
Geranium robertianum, Mycelis muralis, Viola riviniana, Dryopteris
filix-mas, Polystichum setiferum, Rubus fruticosus and Car ex
sylvatica. The more acidic soils are dominated by such species as
Agrostis tennis, Pteridium aquilinum, Festuca rubra, Des-champsia
flexuosa, Anthoxanthum odoratum, Galium her-cynicum, Oxalis
acetosella, Digitalis purpurea and Vaccinium myrtittus along with a
range of bryophytes. Bryophytes are not conspicuous throughout most
of the woods but the two ravines and some of the older trees provide
a useful range of habitats. Hylocomium brevirostre is abundant in
the west of the area. The wood includes a wide range of habitats for
larger mammals and birds and is notable in having a large population
of badgers.
In the south the wood extends
high up the valley of the Afon Ddu
which contains the Ardda Alder Wood. This is a high-level alderwood
at 210-260 m, a type previously common but now extremely rare in
Wales. This was part of the Cistercian monastery of Aberconwy
established in the twelfth century. The survival of the alder
woodland may be because of the more limited extent of sixteenth-
century enclosures in this area compared to similar valleys in
Snowdonia. The shrub layer is well developed in some parts of the
wood but almost completely absent from others, the main species
being hazel but holly and rowan are also common. Spindle occurs but
is rare. The ground flora of the alderwood is extremely varied.
(b) Coed Gorswen SH 7570.
14 ha
The wood lies on the western
side of the more gently sloping lower
Dyffryn Conwy at an altitude of 45-150 m. It is the driest of the
base-rich series with a rainfall of about 130 cm annually. The
underlying rocks are completely masked by glacial drift and
colluvium of mixed composition containing acid sedimentary, acidic
and basic igneous rocks, resulting in a mixture of acidic and base-
rich soils. Several streams and flush lines run through the wood
adding further to the base-rich influence. The result is a diverse
wood consisting of oak, wych elm, alder, ash, sycamore, both birches
and gean. Both sessile and pedunculate oaks and hybrids are present
in the wood but pedunculate types are probably in the majority.
There seems to be a characteristic distribution with pedunculate
types on wetter flushed sites and sessile types on the more freely
draining soils, particularly at the higher west side of the wood.
There is a well- developed shrub layer, and blackthorn are locally
dominant. Other species present include rowan, hawthorn, elder, crab
apple and field maple. The ground flora is equally rich and five
main communities have been described. On freely and imperfectly
drained soils the main species are Oxalis acetosella, Geranium
robertianum, Rubus fruticosus, Viola riviniana, Veronica chamaedrys,
Brachypodium sylvaticum, Geum urbanum, Sanicula europaea and Circaea
lutetiana. Less common plants include Botrychium lunaria and
Epipactis helleborine. On the wetter gleyed soils, in flushes or
beside streams the main species are Ranunculus repens, R. flammula,
Chrysosplenium oppositifolium, Mentha aquatica, Phalaris
arundinacea, Carex remota, C. laevigata, C. nigra, Juncus effusus
and J. acutifiorus.
(c) Ceunant Dulyn
SH 7568.
16 ha.
This site is situated in
the steep-sided valley of Afon Dulyn which
flows east into the River Conwy. The altitude ranges from 75-240 m.
Rainfall is about 152 cm annually but with high humidity within the
ravine. Flow in the river is affected by the Dolgarrog Hydro-
electric Scheme. The underlying rocks are Ordovician sediments and
pumice tuff which have produced acid and moderately base-rich soils
respectively. The acidic soils support oak (mainly Quercus petraea]
and birch woodland with a sparse shrub layer and a ground flora
consisting of such species as Pteridium aquilinum, Agrostis tennis,
Deschampsia flexuosa and Oxalis acetosella. On the more basic soils
the main species is again oak, but this time Q. petraea, Q. robur
and hybrids, along with ash, wych elm, alder and sycamore. There is
a well- developed shrub layer consisting mainly of hazel and a much
richer ground flora including such species as Ranunculus repens,
Carex remota, Angelica sylvestris, Sanicula europaea, Mercurialis
perennis, Brachypodium sylvaticum, Deschampsia cespitosa, Oxalis
acetosella, Viola riviniana, Geranium robertianum, Dryopteris filix-
mas and Rubus fruticosus agg. The Atlantic bryophyte flora is only
moderately rich. |
|
W.III. HAFOD GAREGOG, CAERNARVONSHIRE
SH 6044.
115 ha
Grade 2
This cluster of woods is
situated on a number of low, rocky hills
and ridges rising abruptly from the estuarine flats (now reclaimed)
associated with the Afon Glaslyn. About half the area is woodland
and the other half mire or lake. The tree layer consists of mainly
sessile oak in mixture with birch, rowan and holly, and with a
sparse shrub layer of hazel. The field layer is generally
acidophilous in character, being dominated by Anthoxanthum odoratum,
Festuca ovina, Melampyrum pratense, Potentilla erecta and Oxalis
acetosella, with Pteridium aquilinum in more open areas. There are
historical reasons for supposing this to be an area in which there
has been a long period of continuous woodland cover. In floristics
the wood is fairly typical of western sessile oakwood, but the site
is unusual in being on flat or gently sloping ground, in contrast to
many of the remaining hill woodlands in Wales, most of which occur
on steep slopes as oak hangers. |
|
W.I05. COED
TREMADOG, CAERNARVONSHIRE
SH 5640.
24 ha
Grade i
This woodland lies on cliff
and scree at 15-150 m on the south-
facing scarps of the Moel Hebog massif, overlooking the reclaimed
estuary of the Afon Glaslyn (the Traeth Mawr). The site is strongly
exposed to south-west onshore winds but the rainfall is lower (about
152 cm annually) than for many of the Snowdonian woodlands, and the
aspect is sunny. The underlying rocks are Ordovician slates but
there are several large intrusions of base-rich dolerite which form
high, vertical cliffs. The steep slopes below the cliffs have a
great deal of scree, varying from huge tumbled blocks in the east to
much smaller material at the west end. Soils are mostly thin and
skeletal, and vary from acidic to strongly basic, with fertile brown
earths where there is flushing from the dolerite.
The vegetation varies from
closed woodland to open cliff and scree
communities. The closed woodland varies from an acidophilous type
dominated by sessile oak, with some pedunculate oak, to a
basiphilous ash-hazel type. Beech and sycamore are locally
plentiful. The oakwood has rowan and holly in the shrub layer, and
field communities have Deschampsia flexuosa, Vaccinium myrtillus,
Anthoxan-ihum odoratum, Agrostis tenuis, Teucrium scorodonia and
Pteridium aquilinum. The ashwood has a field layer with grasses such
as Brachypodium sylvaticum and Melica uni-flora, and forbs such as
Mercurialis perennis, Geum rivale, Epilobium montanum, Melandrium
rubrum and Veronica offkinalis.
The woodland shows all
degrees of opening out, to scattered growths
of trees on the screes, and in places a scrubby oakwood spreads up
the less precipitous cliffs. There is a variable development of tall
scrub, mainly of hazel and hawthorn, with lesser amounts of privet
and blackthorn. The screes locally have dense masses of bramble and
there is a good deal of ivy. The flora of the more open habitats is
rich and interesting, with a variety of moderately to strongly
basiphilous species, including Sedumforsteranum, S. telephium,
Origanum vulgare, Hypericum androsaemum, H. hirsutum, Geranium
lucidum, G. robertianum, Chrysanthemum leucanthemum, Polystichum
setiferum, Phyllitis scolo-pendrium, Asplenium trichomanes, A.
adiantum-nigrum, Pterogonium gracile and Marchesinia mackaii. More
acidophilous or acid-tolerant species of rocky habitats include
Sedum anglicum, Teucrium scorodonia, Hypochoeris radicata, Cotyledon
umbilicus, Corydalis claviculata, Dryopteris filix-mas, Polypodium
vulgare and Hedwigia integrifolia.
The interest of the site
is thus partly for the range of woodland
features, but also for the more open scrub and rock communities
which are referable to types discussed under Lowland Grasslands,
Heaths and Scrub. |
|
|
|
|
W.QI. COTHI
TYWI, CARMARTHENSHIRE
SN 7648.
200 ha
Grade i
This is a composite name
for Allt Rhyd-y-Groes and Allt Pen-y-rhiw-
iar and their surrounding upland country (see also U.6). These lie
on a steep north-east-facing valley side overlooking the Afon
Doethie. Silurian rocks, predominantly shales, have weathered to
produce podsols and brown earths of low base-status.
Both woodlands are dominated
by sessile oak, with some particularly
good specimens at Allt Rhyd-y-Groes. The trees in Allt Pen-y-rhiw-
iar are more closely spaced and have been subjected to coppicing in
the past. Associated tree species in both woodlands include ash and
alder on the damper soils with rowan and birch scattered throughout:
wych elm, holly, hawthorn, crab apple and willows (Salix cinerea and
S. auritd) are also present. The shrub layer is not well developed
though hazel is abundant where the oaks have been coppiced.
Blackthorn is marginal and honeysuckle and ivy are restricted to
inaccessible rocks.
The woodland ground flora
is not particularly rich and bryophytes
form an important constituent. On the lower slopes of both woods,
Anthoxanthum odoratum is abundant, replaced by Festuca ovina and
Deschampsia fiexuosa at the upper levels. Other flowering plants
include Vaccinium myrtillus, D. cespitosa, Oxalis acetosella,
Endymion non-scriptus, Geranium robertianum, Filipendula ulmaria and
Chrysosplenium oppositifolium, illustrating the range of soil
conditions. Such ferns as Dryopteris filix-mas and Poly-podium
vulgare are abundant, Hymenophyllum wilsonii and Thelypteris
dryopteris are present. The commonest bryophytes are Polytrichum
spp., Dicranum majus, Rhytidi-adelphus loreus and a cascading stream
has several oceanic bryophytes including jfubula hutchinsiae and
Plagiochila tridenticulata. Bazzania trilobata and Mylia taylori are
also very luxuriant. Nozuellia curvifolia and the rare Sphenolobus
heller anus grow on rotting logs. |
|
|
|
|
W.IOQ. COED CRAFNANT, MERIONETH
SH 6128.
35 ha
Grade i*
This wood is about 1.6
km in length and occupies a northwest-facing
terraced slope on the south-east side of the Afon Artro valley on
the western flanks of the Rhinog massif (U.I2). The wood extends
from 76 to over 210 m altitude. The high annual rainfall (200 cm),
the shaded aspect, the prevalence of moist sea winds and mist, and
the general topographical setting results in locally humid
conditions. The underlying rocks are acidic Cambrian grits of the
Harlech Dome complex, but there are numerous intrusions of base-rich
rocks in the area, resulting in a rich and diverse flora and
vegetation. A second wood, occupying a small valley and east-facing
slope to the west of the Afon Artro, is mostly on more base-rich
soil than the main part to the east.
The dominant tree is oak,
Quercus petraea, with some birch, rowan
and holly (rather rare). In wet areas along streams and in flush
bogs, alder is locally dominant, with willows Salix aurita and S.
cinerea. The shrub layer is poorly developed with scattered hazel
and some hawthorn. The ground flora on moist but well-drained sites
is predominantly grassy with Deschampsia flexuosa, Agrostis spp.,
Molinia caerulea, and an abundance of Potentilla erecta, Galium
saxatile, Pteridium aquilinum, and Melampyrum pratense. Ash and
hazel are abundant in the wood west of the river, and a basiphilous
field layer is well developed here.
Throughout the wood there
are rock outcrops, some of which are
virtually ungrazed, supporting an abundance of Luzula sylvatica and
Vaccinium myrtillus, with Rubus fruticosus agg., Corydalis
claviculata, and in shaded areas Hymenophyllum wilsonii and, more
rarely, H. tunbrigense. These outcrops and boulders in the wood
provide habitats for rare or local Atlantic bryophytes, such as
Dicranum scottianum, Lepidozia pinnata, Adelanthus decipiens, Har-
panthus scutatus, Plagiochila punctata, P. tridenticulata,
Jamesoniella autumnalis, and Bazzania trilobata. The luxuriance of
the bryophyte growth in the wood is one of its most important
features, for besides the common woodland species, it supports
several local species in abundance, for example Hylocomium umbratum,
Leucobryum juniperoideum (only a few other localities in Britain)
and Lepidozia pearsonii.
There is a good epiphytic
lichen growth on the trees and rocks with
Lobaria pulmonaria, Sticta sylvatica, S. limbata, S. fuliginosa and
Sphaerophorus melanocarpus. The western sector with abundant ash is
especially rich in lichens. Rotten logs provide specialised habitats
for several interesting liverworts, such as Tritomaria exsecta,
Scapania umbrosa and Blepharostoma trichophyllum.
In waterlogged areas within
the wood, as on terrace flats, there is
a range of interesting flush bogs with Juncus acuti-florus,
Hypericum elodes, and Scutellaria minor, and a range of bryophytes
including Sphagnum imbricatum, S. contortum, and S. warnstorfianum.
Small rivulets flowing through the wood provide habitats for several
rare hepatics, such as 80 Woodlands
Porella pinnata, Aphanolejeunea
microscopica, Cephaloziella
pearsonii, and Jubula hutchinsiae.
The principal interest
of this wood is the rich and varied Atlantic
bryophyte and lichen flora, and the intricate woodland mosaic
related to topographical features. It provides one of the finest
examples of the range of woodland bryophyte habitats in western
oakwood, and in north Wales is second only to Coed Ganllwyd in this
respect. |
|
W.ioy. COEDYDD DYFFRYN
MAENTWROG,
MERIONETH Grade i*
a) Coed Camlyn-Ceunant
Llennyrch SH 6539. 119 ha
Coed Camlyn is situated
on steep slopes on the south side of the
Ffestiniog Valley, and the main section of the wood has a north-west
aspect, but other parts face north and southwest. Altitude ranges
from 15-150 m and exposure to wind, particularly on the upper
slopes, is severe, the south-west winds having a more or less clear
run from the sea about 8 km distant. Rainfall is about 180 cm
annually. The underlying rocks are Upper Cambrian and consist mainly
of acidic slates. These rocks are exposed in cliffs at the top of
the slopes, whilst the lower slopes are mainly covered with scree of
periglacial origin on which freely draining acidic skeletal soils
are formed. In the main wood the tree layer is dominated by sessile
oak whilst birch is locally co-dominant or forms an understorey in
some more open areas. Holly, beech and sycamore are also present.
There is a small outlying area dominated by birch and in another
sweet chestnut is common. The southern end of the wood has few tall
shrubs and the ground flora is almost completely dominated by
bilberry, with Deschampsia flexuosa and Molinia caerulea
subdominant. Bracken dominates the field layer in more open areas.
In the north bilberry is less prominent, there is a sparse
understorey of hazel and the ground flora is dominated by Agrostis
spp., Deschampsia flexuosa, Oxalis acetosella and bryophytes. There
were formerly several groups of conifers in the wood but these have
recently been removed. Rhododendron ponticum is present in parts of
the wood, but its spread is now largely under control.
At its south-west end,
Coed Camlyn bends round into the deep wooded
glen of Ceunant Llennyrch which carries the stream from the
Trawsfynydd reservoir and contains one of the finest river gorges in
north Wales. The rocks are mainly Cambrian slates and shales, but
there are basic intrusions, and soil conditions vary from acidic to
basic, giving the usual variation from sessile oak to mixed
deciduous woodland. In places here, however, the oakwood has been
replaced by serai birch. On the precipitous sides of the gorge,
woodland species (e.g. Luzula sylvatica and numerous forbs) which
suffer from sheep- grazing are able to flourish, but the most
outstanding feature of the glen is the extremely rich Atlantic
cryptogamic flora. The two ferns Dryopteris aemula and Hymenophyllum
tunbrigense probably grow more abundantly here than anywhere else in
Wales, and Osmunda regalis occurs more sparingly. The bryophyte
flora compares favourably with that of Coed Ganllwyd and includes
species such as Sematophyllum demissum, Hylocomium umbratum, Hypnum.
callichroum, Adelanthus decipiens, Colura calyp-trifolia,
Drepanolejeunea hamatifolia, Harpalejeunea ovata, Radula valuta and
Marchesinia mackaii.
The gorge and its flora
provide a complement to the hanging woods of
Coed Camlyn, which do not have a block-strewn floor and have only
the commoner species of Atlantic bryophytes. The construction of the
Trawsfynydd reservoir has greatly reduced the flows of the stream
through Ceunant Llennyrch, but this
has apparently had no
significant effect on atmospheric humidity and the richness of the
hygrophilous flora.
The lichen flora shows
a fine development of the lowland Lobarion
community on the large sheltered oaks at the lowest part of the
valley, with least rainfall and richest soil. Rinodina isidioides
and Pannaria sampaiana are particularly noteworthy here; the latter
species, recently described from Iberia, proves to be rare though
widely scattered in western Britain from the New Forest and Devon
through north Wales to western Scotland. Other rarities include
Thelopsis rubella and Parmelia horrescens.
Although the upper part
of the valley has a magnificent bryophyte
flora, the lichen vegetation is represented by the species-poor
Parmelietum laevigatae. However, there occurs an undescribed Bacidia
sp. with an isidiate thallus which is known to be widespread but
rare in old southern and western forest fragments.
Thelotrema lepadinum, a
lichen which seems to be a very good
indicator of ancient forest relict sites, also occurs, as does
Haematomma elatinum and Lecidea cinnabarinum of similar occurrence.
The site is particularly
important lichenologically because in this
one forested valley there exists both the lowland type of oakwood
and its typical lichen flora, and also the upland types with the
zone of transition.
(b) Coedydd Maentwrog-Coed
Cymerau
SH 6741, SH 6742, SH 6841,
SH 6842. 147 ha
These lie on the north
side of the Vale of Ffestiniog, Coed Cymerau
occupying the steep slopes of the Afon Goedol ravine, whilst Coedydd
Maentwrog extends 2.4 km along the main valley. At Coed Cymerau
altitude ranges from 45-150 m and apart from the upper slopes on the
east side of the river the wood is very sheltered. Rainfall is 200
cm annually but within the confines of the narrow valley atmospheric
humidity is markedly higher than in surrounding areas. There is a
rather shallow gorge with a small waterfall near which Hymenophyllum
tunbrigense grows. The underlying rocks are Cambrian slates which
weather to produce an acidic soil. On the west side of the river
much of the soil is little more than stabilised scree originating
from a line of cliffs above. In the east the soil is deeper in
places and may be partly formed on drift but throughout the wood as
a whole there are numerous areas of exposed rock or tumbled detached
boulders.
The tree layer is dominated
by oak Quercus petraea with only a small
contribution of Q. robur types. Birch is a scattered co-dominant and
becomes locally dominant. Rowan is also common usually as a
subdominant and there are a few widely scattered individuals of ash,
sycamore, alder, holly and crab apple. Throughout most of the wood
the shrub layer is poorly developed but in some slightly flushed
areas particularly in the north and west, there is a moderate
density of hazel. Molinia caerulea, Deschampsia flexuosa and
Agrostis tennis are the three main ground flora dominants under
closed canopy. In open areas bracken takes over. In contrast to Coed
Camlyn, bilberry has a fairly minor role here. Other common
herbaceous species include Melampymm pratense, Oxalis acetosella,
Galium hercynicum and Potentilla erecta. Bryophytes dominate large
areas of the wood particularly in the more rocky areas and a wide
range of species has been recorded including several rare Atlantic
species, though this site is less rich than some other Merioneth
woodlands. Other habitats represented within the wood include
several small acidic mires (with Sphagnum imbricatuni), grassland
(with Wahlenbergia hederacea) and a small area of open partly
stabilised scree on the west side. The river traversing this glen is
heavily polluted by sewage from Blaenau Ffestiniog.
Coedydd Maentwrog has an
altitude range of 15-150 m. There is also a
small detached area a few hundred metres from the west end of the
main wood running down to Llyn Mair. The main aspect of the wood is
south and it is therefore sun exposed. Rainfall is about 180 cm
annually, but there is not the high atmospheric humidity associated
with the ravine at Cymerau. This wood is also considerably less
humid than the north-west-facing slopes of Coed Camlyn which receive
little direct sunshine. The underlying rock is Upper Cambrian shale.
As at Camlyn these have been frost shattered to produce extensive
periglacial screes upon which acidic soils have developed, but rock
weathering at Maentwrog has produced a higher proportion of finer
fractions in the soil which is generally richer and more retentive
than at Camlyn. The dominant species in the tree layer is sessile
oak but there are a number of trees with pedunculate characters
indicating some hybridisation. Birch is also common either as a
scattered co-dominant or a local dominant round clearings. Other
species present include rowan, ash, alder and sycamore. The shrub
layer is poorly developed with only scattered hazel, and, though
Rhododendron ponticum is common in the west end of the wood, its
spread is under control. The ground flora beneath the tree canopy is
dominated mainly by grasses (Anthoxan-thum odoratum, Agrostis spp.,
and Deschampsia flexuosa) and mosses. The wood has been more
disturbed in recent times than its neighbours, and large gaps are
dominated by dense bracken. The oak trees of Coedydd Maentwrog have
a much wider age distribution than the other woods in the Ffestiniog
Valley (100-200 years) compared with 100-150 at Cymerau and about
100- 120 at Camlyn. The different ages, however, tend to be in
groups rather than intimately mixed as in some parts of Cymerau.
(c) Coed y Rhygen SH 6836.
27 ha
The wood lies on the western
side of Trawsfynydd Lake at an altitude
of 200-260 m. Rainfall is about 200 cm annually, and the proximity
of the lake may add to the local atmospheric humidity. Topography
within the wood is extremely broken with ridges of rock running up
the slope, and there are numerous small cliffs, slabs and block
litters. The area lies at the north edge of the Harlech Dome and the
underlying rocks are mainly hard Cambrian grits, acidic and
resistant to weathering. Except at the north-west end of the wood
where there is a deeper acidic soil on drift material, the soils are
extremely shallow and skeletal (on the rock ridges) or wet and peaty
(in the hollows between). The main species in the tree layer are
sessile oak and birch. The most common composition is large, old oak
trees set in a matrix of birch but, at the east end of the wood,
birch is dominant and there has probably been selective removal of
oak over a long period. Rowan is common and scattered throughout the
wood and there are a few willows in the wet hollows. The shrub layer
is poorly developed, being limited to a few patches of hazel in
areas of slight enrichment. The ground flora is generally bryophyte-
dominated although Deschamp-sia flexuosa is common throughout and
both bracken and bilberry may attain local dominance. Local
enrichment of soil is indicated by the local presence in the field
layer of Mercurialis perennis, Geranium robertianum, Lysimachia
nemorum and Filipendula ulmaria. The characteristic woodland mosses
such as Rhytidiadelphus loreus are in profusion in rocky places but
over 100 other bryophytes occur. Many species grow with a luxuriance
only equalled in western Scotland, notably Plagiochila spinulosa,
Scapania gracilis, Lepidozia pinnata, Bazzania trilobata and
Saccogyna viticulosa. Hymenophyllum wilsonii is common amongst the
rocks and the older trees are covered with epiphytic species
including P. punctata. Rarer bryophytes are also present and these
include Sematophyllum demissum, Hypnum calli- chroum, Hylocomium
umbratum, Thuidium delicatulum, Adelanthus decipiens, Harpanthus
scutatus, Plagiochila tridenticulata, B. tricrenata and Lepidozia
pearsonii. The richness of the bryophyte flora points to Post-
glacial continuity of tree cover at the site.
The epiphytic lichen flora
is limited to the Parmelietum laevigatae
community on highly leached acidic bark with only traces of the
Lobarion community (Pannaria pityrea, Parmeliella corallinioides,
Sticta sylvatica, Dimerella luted) on a few more sheltered old
trees. The epiflora, in fact, comprises only 39 species of lichens,
a remarkably low number.
Indicators of ancient,
relic woodland present are Thelo-trema
lepadinum, Haematomma elatinum, Lecidea cinna-barinum, and probably
the Lobarion spp. mentioned. Of oceanic species, the wood possesses
Menegazzia terebrata and Cetrelia cetrarioides as well as the common
Parmelia laevigata, Mycoblastus sanguinarius, Sphaerophorus spp. and
Ochrolechia tartarea of the Parmelietum laevigatae.
The rock flora is interesting
and typical of highly leached acid
environments with several Cladonia spp. and the oceanic Akctoria
bicolor.
The larger peaty areas
between the rock ridges often have no trees
on them and are wet grass-heaths or even soligenous mires dominated
by such species as Myrica gale, Molinia caerulea and Erica tetralix.
(d) Ceunant Cynfal SH 7041.
10 ha
This wooded ravine below
Ffestiniog is one of the finest river
gorges in the whole of Britain. The Afon Cynfal has cut across the
dip of acidic and mildly basic Cambrian slates to a depth of 30-45
m, and much of the gorge is
flanked by sheer cliffs
and interrupted by several considerable
waterfalls. As such the area is of outstanding geo-morphological
interest.
The variety of rock types
results in a mosaic of oakwood communities
on the acidic sites and mixed deciduous woodland on the richer
soils. The oakwood along the top of the gorge is an excellent
Quercus petraea wood, with some birch, rowan and holly. The ground
flora is grazed in parts and it is therefore predominantly grassy,
except in steep, ungrazed situations where there is an abundance of
Luzula sylvatica and Vaccinium myrtittus. Seepage areas within the
wood are characterised by banks of Chrysosplenium oppositifolium,
growing with Trichocolea tomentella.
Bryophytes are abundant
in the wood in a variety of habitats, for
example on the woodland floor, on blocks, on rotten logs, and as
epiphytes. Atlantic species are particularly well represented with
Dicranum scottianum, Hylocomium umbratum, Lepidozia pinnata, and L.
pearsonii, and the filmy ferns Hymenophyllum wilsonii and H.
tunbrigense. Epiphytic lichens are abundant with Lobaria spp.,
Sticta spp., and Parmeliella atlantica. Several notable bryophytes
have been found in the gorge including Jubula hutchinsiae, Metzgeria
hamata, Isothecium holtii, Tetraphis browniana, Drepanolejeunea
hamatifolia, Grimmia hartmanii, and Harpalejeunea ovata.
The small side-stream flowing
into the Afon Cynfal from Ffestiniog
carries much sewage and seriously pollutes the lower kilometre of
the river in the glen, but the better upper section is unaffected.
There is a general similarity to the gorge of Ceunant Llennyrch, but
many differences in detail, and the Afon Cynfal, unlike the other
stream, is undiminished in flow through damming higher up.
(e) Ceunant Llechrwd, Gellilydan
SH 6840.
7 ha
Below the hamlet of Gellilydan
and between the wooded glens of
Ceunant Llennyrch and Ceunant Cynfal, a third north-west-flowing
stream which feeds the Vale of Maent-wrog has cut a deep ravine.
This glen also is wooded, mainly with sessile oakwood, but contains
fragments of mixed deciduous growth. A number of Atlantic bryophytes
are represented and there is a small colony of Osmunda regalis. On
the whole, however, this glen is less rich floristically and less
spectacular in the depth and abruptness of its gorge than the other
two mentioned. It is, however, an integral part of the Coedydd
Dyffryn Maentwrog complex and was once continuous with the woods of
the other adjacent sites. |
|
W.IOS. COED
GANLLWYD, MERIONETH
SH 7224.
25 ha
Grade i*
The wood occupies a comparatively
gentle slope on the east side of
the Rhinog Mountains at 60-140 m, and is traversed along its north
side by the rocky gorge of the Afon Gamlan with its well-known
waterfall Rhaiadr-ddu. The local rainfall is about 190 cm annually
and the atmospheric humidity is accentuated by the sheltered nature
of the site and by river spray immediately around the falls. The
underlying rocks are Cambrian grits, acidic, hard and resistant to
weathering, but there are also several intrusions of base-rich
dolerite outcropping in the wood. Several smaller streams run
through the mid and southern sections of the wood and there are
significant areas of flushing from the base-rich rocks, giving a
mixture of acidic and basic soils.
The tree layer is dominated
by oak (mainly Quercus petraea but some
Q. robur types are present) with distinctive strips of ash along the
various streams. Birch and sycamore are widely scattered throughout
the wood and alder is locally dominant in wet places. Other species
present include wych elm, beech, rowan and gean. Development of the
shrub layer is poor, the most common species being hazel, but holly,
hawthorn, blackthorn and alder buckthorn are all present in small
quantities. Bracken dominates large areas of the ground flora whilst
in other more shaded areas bryophytes are abundant in both number
and species. In a few areas there is a true herb layer and on drier
acidic soils Agrostis sp., Anthoxanthum odoratum, Festuca ovina,
Galium hercynicum, Endymion non-scriptus, Digitalis purpurea,
Potentilla erecta and Melampyrum pratense are common, whilst flushed
sites contain such species as Circaea lutetiana, Mercurialis
perennis, Brachypodium sylvaticum, Geranium robertianum, Geum
urbanum and Prunella vulgaris. Small acidic soligenous mires occur
which contain Sphagnum imbricatum.
The wood is famous for
the presence of a wide variety of rare
oceanic ferns, liverworts and mosses. Parts of the wood are strewn
with boulders of coarse grit and it is in and around these that
bryophyte communities are best developed, and in the actual gorge.
On the shady and/or wet rocks beside the waterfalls and streamlets
are species such as Campylopus setifolius, Leptodontium
recurvifolium, Hyloco- mium umbratum, Colura calyptrifolia, Jubula
hutchinsiae, Drepanolejeunea hamatifolia, Harpalejeunea ovata,
Radula valuta, R. aquilegia, Frullania microphylla, Plagiochila tri-
denticulata and the ferns Hymenophyllum wilsonii, H. tunbrigense and
Dryopteris aemula. On slabs and rocks in the woods and beside the
stream there is a great abundance of the rare Sematophyllum
demissum, and S. novae- caesareae is recorded. Adelanthus decipiens
is locally abundant and Mylia cuneifolia has been found here in its
only station outside Scotland. Such species require warm humid
conditions and most are found in and around the main gorge of the
Afon Gamlan and its tributary streams. The presence of so large an
assemblage of rare and local Atlantic bryophytes is believed to
indicate continuity of at least some woody cover throughout the Post-
glacial Period. Although there is evidence that the present oaks
were planted together during the nineteenth century, it is
inconceivable that so many drought- sensitive species could have
survived if the whole area had been totally cleared of woodland or
scrub at any one time.
The area also contains
important geological features including one
of the few localities on the Harlech Dome yielding Middle Cambrian
fossils. |
|
W.II3. COED
LLETY WALTER, MERIONETH
SH 6027.
45 ha
Grade 2
This woodland lies at 60-80
m on fairly level ground, north of the
Afon Artro, and at the mouth of the valley, about 5 km from the sea.
The bed rock is Cambrian grit and the rainfall about 200 cm
annually. The wood is young, 30-40 years old perhaps, with a
dominance of naturally regenerated oak and birch. Other species
present include ash, alder, rowan and holly. A few large Scots pine
and beech remain as remnants of the previous woodland. The ground
flora is predominantly acidophilous but there are local occurrences
of Brachypodium sylvaticum and Geranium robertianum indicating some
base enrichment. The wood is notable for a wide range of habitats in
the form of rock outcrops, short slopes with various aspects,
streams, wet flats and glades. |
|
W.II4- COED
LLECHWEDD, MERIONETH
SH 5932.
55 ha
Grade 2
The wood occupies a steep
north-west-facing slope just north of
Harlech, looking out over Morfa Harlech. Altitude ranges from 15-180
m and the exposure to wind is moderate to severe. The underlying
rocks are Cambrian and the diverse woodland vegetation suggests the
presence of base-rich rock outcrops. The tree layer is dominated by
oak but a wide range of other trees are present, including less
common species for this area, such as gean. There are both
acidophilous and basiphilous elements
in the ground flora, as
indicated by the presence of heather and Allium ursinum. This is a
good example of a hill wood with considerable ecological diversity
resulting from varying base content of the soil. |
|
W.II2. COED
MAES YR HELMAU: TORRENT WALK, MERIONETH
SH 7518.
25 ha
Grade 2
This deep rocky glen near
Dolgellau has fringing woodlands with both
sessile oak on acidic soils and mixed deciduous wood on basic soils.
Some of the oaks in particular are tall, well-grown trees, and this
site is regarded as of national importance mainly for the quality of
these two contrasting types of woodland and their respective field
layers. The wood is ungrazed, and the ash-wych elm-hazel woodland
has fine examples of herb-dominated field communities
with Mercurialis perennis,
Filipendula ulmaria, Asperula odorata and
Brachypodium sylvaticum. There are a few non-indigenous trees, but
small-leaved lime in the glen may well be native. The gorge carries
a large stream but is less deep and spectacular than the Coedydd
Dyffryn Maentwrog gorges (W. 107). There are block strewn areas of
the woodland floor, with some moisture- and shade-loving ferns and
bryophytes (e.g. Hymenophyllum wilsonii, Scapania gracilis,
Plagiochila spinulosa and Bazzania trilobata) and many trees are
thickly clothed with moss. On the whole though, the Atlantic element
of the flora is not outstanding, and the more notable species (e.g.
Hymenophyllum tunbrigense, Iso-thecium holtii, Radula valuta and
Jubula hutchinsiae) are confined to the gorge itself.
The contrast between the
Coed Macs yr Helmau and Atlantic bryophyte-
rich woods such as Coed Ganllwyd appears to result not from
difference in present conditions -since none is obvious - but from a
different history of management. The Coed Macs yr Helmau woods
appear to have been replanted after a period of clearance during
which moisture-loving ferns and bryophytes disappeared, except from
the actual ravine. When the wood grew up again, only the more common
species were able to spread back to recolonise the suitable habitats
which developed. By contrast, at Coed Ganllwyd, it would appear that
there has been continuity of woody cover - if only of scrub - over
at least part of the site throughout the Post-glacial Period, so
that drought-sensitive species survived somewhere and spread again
when high forest was restored after nineteenth-century clearance and
replanting of oak and beech. |
|
|
|
|
W.IOI. COED
ABER EDW, RADNOR
so 0847.
16 ha
Grade 2
This wood lies to the south
of the River Edw. The steep north-facing
slopes of the valley carry both oakwood and mixed deciduous wood;
the former occurring on acidic and the latter on the calcareous
shaly beds of the Ludlow Group of the Silurian. Where the calcareous
rock outcrops the main trees are ash, wych elm and hazel but there
are some field maple and rowan and a few trees of small-leaved lime.
There is also some elder and gooseberry but birch is scarce. The
ground flora although sparse is species-rich and includes
Polystichum setiferum, Asplenium trichomanes, Phyllitis
scolopendrium, Melica uniflora, Brachypodium sylvaticum, Poa
nemoralis, Saxifraga hypnoides, Mycelis muralis, Mercurialis
perennis, Chrysosplenium oppositifolium, Glechoma hederacea,
Veronica montana, Hedera helix, Geranium robertianum, G. lucidum,
Anomodon viticulosus, Thamnium alopecurum, Neckera crispa, N.
complanata, Camptothecium sericeum, Brachythecium rutabulum, B.
plumosum, Eurhynchium praelongum, Mnium rostratum, M. undulatum,
Metzgeria furcata, Plagiochila asplenioides and var. major,
Madotheca platyphylla, Marchesinia mackaii.
In other areas oak is dominant
and this dominance is clearly
associated with scarcity of lime in the parent rock which in turn
seems to depend on the disappearance of the calcite veins. The flora
of these acidic rocks is poor and includes the common woodland
bryophytes. There is a local abundance of Vaccinium myrtillus and
grasses such as Holcus mollis, Anthoxanthum, Festuca ovina and
Deschampsia flexuosa.
Presence of small amounts
of lime in the generally acidic rocks is
marked by an increase in richness of the ground flora although oak
remains dominant. |
|
W-94- BLACKCLIFF-WYNDCLIFF-PIERCE
WOODS:
CLOGWYN DU-CLOGWYN
GWYN-COED PYRS, MONMOUTHSHIRE
ST 533988-533942.
180 ha
Grade i
This extensive stand lies
on the right bank of the lower Wye and
stretches from Castle Wood in the south to Blackcliff Wood in the
north, and includes those woods on the Live-oaks meander which have
so far been spared destruction by quarrying. The area is composed of
Carboniferous strata, mostly limestone but including a small
proportion of acidic rocks, and includes the two cliffs of
Blackcliff and Wyndcliff and small river cliffs elsewhere,
precipitous slopes along, for example, Piercefield Cliffs, and
gently sloping ground in the centre of Pierce Woods. The woods cover
an altitudinal range greater than 230 m and have a variety of
aspects lacking only west- facing slopes. The woodland is mostly
mature high forest, some of it grown up from coppice-with-standards.
The principal species are beech, yew, small-leaved lime, pedunculate
and sessile oaks, wych elm and ash. Although these are commonly
found in intimate mixtures, one or two species assume dominance
locally. This is particularly evident on the cliff faces and the
scree slopes where beech and yew dominate, and on some of the lower,
gentler slopes where sessile oak and lime are dominant.
Structurally, there is considerable variety including nearly open
scrub on the cliff faces, mixed-age woodland on Piercefield Cliffs
and even-aged, former coppice-with-standards in Martridge Wood. The
subordinate tree and shrub species include a variety of Sorbus spp.
(S. torminalis, S. aria, S. porrigentiformis, S. anglica and S.
rupicola). The ground flora is limited, partly by the heavy shade
but also by the lack of surface water. Floristically, the site has a
number of rare and local species, including Geranium sylvaticum and
large-leaved lime.
These woods represent part
of the range of structural and floristic
variation in the extensive Wye valley woods, particularly the lower
region of limestone. These woods are chosen, rather than the woods
on the left bank from Caswell Wood to Chapelhouse Wood, because they
are less altered by recent forestry operations, include a greater
variety of habitat and woodland types and, on available information,
are floristically the richer. |
|
W-92. COED
Y CERRIG, MONMOUTHSHIRE
802921.
50 ha
Grade i
This wood lies on rocks
of the Old Red Sandstone series in a
secluded valley within the boundary of the Brecon Beacons National
Park. Two woodland types are present, a hanging wood on steep slopes
giving way to a wet wood on the valley flats. The latter is
dominated by alder, with willows, blackthorn and Rosa spp. in the
shrub layer. Herbs in abundance include Chrysosplenium
oppositifolium, Ranunculus repens, Juncus spp. and Filipendula
ulmaria. Both the north- and south-facing slopes, up to 300 m, are
dominated by sessile oak with some good specimens. Also in the
canopy and locally abundant are ash, elm and silver birch. The
understorey is well developed, with field maple, rowan, crab apple,
holly and hazel. Shrubs such as hawthorn and elder occur, and the
moss Cryphaea heteromalla grows on elder. The wood is apparently
ungrazed and species composition of the ground flora varies from
mesophilous to base-rich types. This includes Anemone nemorosa,
Endymion non-scriptus, Viola spp., Brachypodium sylvaticum, Primula
vulgaris, Mercurialis perennis, Arum maculatum, Orchis mascula,
Silene dioica, Paris quadrifolia, Chrysosplenium alternifolium and
Lysimachia nemorum; patches of Lathraea squamaria are frequent. More
acidic areas with Deschampsia cespitosa, Digitalis purpurea, Galium
hercynicum and Luzula pilosa also occur. |
|
W.I02. COOMBE WOODS: COED
Y CWM,
MONMOUTHSHIRE
ST 4593.
35 ha
Grade 2
This complex of woods lies
on a narrow, steep-sided valley of the
Cas- Troggi brook where it cuts through Carboniferous Limestone.
It includes Coombe Wood itself, Common Wood on the opposite side of
the valley, those parts of Llanmelin Wood which have not been
replanted with conifers, and other woodlands which form a contiguous
group. Almost all the woodland lies on steeply sloping ground with
strongly calcareous soil in a matrix with limestone fragments, but
small areas occupy gently sloping ground in both the plateau and
valley-bottom situations, where the soil is heavier, less stony,
less well drained and locally with impeded drainage, but still
calcareous. The woodland is mixed deciduous with beech, ash, wych
elm, small-leaved lime, pedunculate oak, field maple and hazel the
most abundant, but with many other species present, including
whitebeam. Over large areas the ground flora is dominated by dog's
mercury, mixed with Allium ursinum at the base of the slopes, but
there is a good deal of variation from this, with areas of
Convallaria majalis.
Coombe Woods is best regarded
as an alternative to the Blackcliff-
Wyndcliff-Pierce Woods grade i site (W.Q4). It is similar in that
much of the woodland is mature high forest derived from coppice; in
the intimate mixture of the most abundant species, with only small
areas of single-species dominance; and in possessing a hill fort
occupied by similar mixed deciduous woodland. |
|
W.93- SALISBURY WOOD: COED
SALSBRI,
MONMOUTHSHIRE
ST 4289.
30 ha
Grade i
Salisbury Wood lies on
the steep slopes and summit of hills composed
of limestone, calcareous shales and calcareous head. Much of the
woodland on the slope is an intimate mixture of small-leaved lime,
ash, wych elm and hazel with much gean, forming high forest derived
from coppice. The
plateau areas have two
types of woodland on partly drained, neutral
clay: ash-gean coppice now grazed by cattle occupies the south-
western arm of the wood, and coppice-with-standards pedunculate oak
over small-leaved lime, ash and hazel occurs round a complex of
parish boundaries and associated pollarded trees. The ground flora
is predominantly calcicolous, with Mercurialis perennis, Galium
odoratum, Brachypodium sylvaticum, Rubus fruticosus agg. and
Phyllitis scolopendrium perhaps the most abundant in a rich mixture
not clearly dominated by any one species.
This wood is selected as
an example of mixed deciduous woodland,
with a particularly rich flora. It has several other important
characteristics. Both oaks and birches are completely absent from
most of the wood. Structurally, the stand has a variety of types
based on the coppice system, one of which, the ash-gean, is very
rare. It lies on a complex of parish boundaries along which are
numerous fine, ancient, pollarded trees. In management and floristic
terms it appears to be closely allied to the eastern mixed deciduous
coppices on calcareous soil, a type which extends along the north
Cotswolds and into south Wales. |
|
W.95- WYE
GORGE: HAFAN GWY, MONMOUTHSHIRE-GLOUCESTERSHIRE-
HEREFORDSHIRE
so 5414. 240 ha
Grade i*
These woodlands lie on
either side of a spectacular meandering river
gorge cut through rocks of Old Red Sandstone and Carboniferous
Limestone series. They extend from the area of the Far Hearkening
Rock to Elliotts and Court Woods, and include Lady Park Wood and the
riverside parts of Lords Wood and Mailscot Wood.
Lady Park Wood is mixed
deciduous woodland of an exceptional
character. It lies at the northern end of High-meadow Woods on
slopes and cliffs above the River Wye on Carboniferous strata which
give rise to three major soil types: shallow, stony, limestone
soils, light loams derived from drift of Old Red Sandstone origin
and clay loams derived from shales. This woodland is exceptionally
rich in tree and shrub species, including sessile oak, beech, ash,
small- leaved lime, wych elm, field maple, silver birch, whitebeam,
wild service and the only stand in Britain where large-leaved lime
is an appreciable constituent of the canopy. Much of the Wood has
been cut over in recent decades and now constitutes coppice regrowth
and saplings, but a scattering of mature trees, mainly beech, has
survived. The ground flora varies with soil conditions, with much
Luzula sylvatica on the light loams, Deschampsia cespitosa and Rubus
caesius on the clays, and calcicolous communities with Mercurialis
perennis on the limestone. Numerous rare species have been recorded,
including the tree species Tilia platyphyllos, Sorbus anglica and
the rare hybrid S. torminalis x aria.
On the opposite bank are
the Seven Sisters Rocks. These limestone
pillars are important refugia for certain rare grassland species
including Carex humilis, C. montana, C. digitata and Geranium
sanguineum. In adjacent Lords Wood a number of disused stone mines
are important overwintering sites for greater horseshoe bats.
Coldwell Rocks are north-facing cliffs (75 m) rich in bryophytes and
ferns. |
|
|
|
|
W.IOO. GLANNAU,
RADNOR
SN 9065.
25 ha
Grade 2
This site on Silurian shales
and sandstones occurs on the steep
slopes above the Garreg-ddu reservoir which bounds it on the east
and south. The soils vary in base content and though dominated by
sessile oak, three distinct blocks occur. On basic soils at the
northern end a dense mixture of wych elm, oak, hazel, willow and
birch grows over abundant Mercurialis perennis with Circaea
lutetiana and Geranium robertianum. Outcrops of rocks support
Asplenium tri-chomanes, Neckera crispa, Tortella tortuosa, Bartramia
halleriana, Brachythecium plumosum and Ctenidium mollus-cum
indicating their moderate lime content. The central area contains a
less dense growth of oaks, 15-18 m in height, with a few birch and
rowan over a bracken- dominated floor with patches of moss-rich
grassland with Deschampsia flexuosa, Digitalis purpurea, Galium
hercynicum and Oxalis acetosella. Nowellia and Lepidozia reptans
cover fallen, rotting tree trunks. At the south end, sycamore and
beech increase in abundance with a scattering of conifers. Sacco-
gyna viticulosa and Plagiochila spinulosa are abundant here and
other species include Athyrium filix- femina, Dryopteris filix-mas,
Blechnum spicant and Deschampsia cespitosa. |
|
|
|
|
W.88. CWM
CLYDACH, BRECKNOCK SO 2112. 2O ha
Grade i
This reserve, which is
within the Brecon Beacons National Park,
consists of two blocks of woodland, the upper Coed Fedw-ddu and Coed
Ffyddlwn, both on the south side of the Afon Clydach ravine. The
underlying Millstone Grit and Carboniferous Limestone provide both
acidic and base-rich conditions. The soils are shallow, stony and
boulder strewn, and podsols only lie on the gentler slopes. Litter
up to 50 cm has been recorded and it decomposes rapidly, partly
because of the extreme dampness at the bottom of the valley which
rarely receives any sun.
Beech is dominant in the
canopy throughout, and on the shallower
well drained soils sessile oak is a co-dominant with birch. Rowan,
hawthorn, hazel, blackthorn and Salix atrocinerea are in the shrub
layer.
Where the soil is wet with
a deeper clay overlying limestone, wych
elm is co-dominant with ash, and yew, holly, elder, as well as
hazel, are in the understorey. There is a range passing through pure
beechwood between these two woodland types. The poor, acidic soils
characteristically have a herb layer dominated by Deschampsia
flexuosa, accompanied by species including Blechnum spicant,
Dryopteris borreri, Luzula sylvatica and Athyrium filix-femina with
locally frequent Vaccinium myrtillus and Pteri-dium aquilinum. Where
the soil is neutral, base-rich and poorly drained, Deschampsia
cespitosa dominates the herb layer in association with Brachypodium
sylvaticum, Epi-lobium montanum, Mercurialis perennis, Mycelis
muralis, Phyllitis scolopendrium, Polystichum setiferum and P.
lobatum. Allium ursinum is locally abundant. Accumulations of
Sphagnum spp. and Leucobryum glaucum also occur.
Hawthorn scrub and a mixed
scrub community occur on the margins and
river flushes; stream-bank communities and limestone outcrops with
yew add to the variety of habitats within the reserve boundary.
The trees are not markedly
even-aged and regeneration appears to be
successful. Although it has been recorded growing elsewhere in the
locality associated with the Carboniferous Limestone, Cwm Clydach
appears to be the largest and therefore the best representative area
of native beech on the western fringe of its natural distribution in
Britain.
W.Sg. PENMOELALLT,
BRECKNOCK
so 0109.
7 ha
Grade i
This Forest Nature Reserve
comprises a small strip of mixed
deciduous woodland owned by the Forestry Commission overlying a
narrow Carboniferous Limestone belt which forms a low escarpment.
The major interest is the presence of three well-developed specimens
of Sorbus leyana, endemic here, and the abundance of S.
porrigentiformis. However, the Reserve bears a type of woodland now
rare in Wales. On the limestone scree the tree cover is dominated by
ash together with wych elm and rowan. The ground flora has much
Mercurialis perennis, Geranium lucidum and
Asperula odorata, and calcicolous
bryophytes are well represented on
the rocks.
On deep clay soil towards
the southern end of the woodland the tree
cover is mixed and is dominated by pedunculate oak together with
ash, elm, rowan and silver birch. Small-leaved lime is also present
and hazel is frequent in the shrub layer. Abundant species of the
ground flora are Endymion non-scriptus, Oxalis acetosella, Viola
riviniana and V. reichenbachiana.
W.QO. COED RHEIDOL, CARDIGANSHIRE
SN 7478.
75 ha
Grade i
The Rheidol valley sides
are covered in mainly oak woodland over
much of their length, with the best stands immediately above and
below the Rheidol Falls. At Devil's Bridge there is a confluence of
twin streams which have cut deeply through Silurian sediments to
form deep gorges clothed for the most part in even-aged sessile oak
woodland with some birch and rowan. Beneath this on the acidic brown
earth and podsol soils, the field layer is strongly calcifuge in
character, i.e. of Vaccinium myrtillus, Molinia caerulea,
Deschampsia flexuosa and Melampyrum pratense, with a strong
bryophyte component, e.g. Dicranum majus, Leucobryum glaucum and
Eazzania trilobata, reflecting the high humidity in the ravine.
Locally in the acidophilous woods birch is dominant, but the main
variation is produced by river- and streamside flushing. Here mixed
deciduous woodland of sessile oak, ash, wych elm and hazel with rare
small-leaved lime has developed with a basiphilous ground flora of
Circaea lutetiana, Sanicula europaea, and ferns. A number of
Atlantic bryophytes are present, Jamesoniella autumnalis, Radula
aquilegia, Marchesinia mackaii, Cepha- loziella pearsonii,
Harpakjeunea ovata, Scapania gracilis, Jubula hutchinsiae, Saccogyna
viticulosa, Lepidozia pinnata and L. pearsonii, and some local
vascular plants, including Trollius europaeus, Festuca altissima,
Meconopsis cambrica, Hymenophyllum tunbrigense, Asplenium
septentrionale and Dryopteris aemula. The site extends below the
Rheidol Falls to the western end of Allt Ddu where on either side of
a tributary stream in sessile oak coppice woodland, ranging in age
up to 150 years, there is a fine example of contrasting ground flora
types on broadly east- and west-facing slopes.
W.QI. COTHI
TYWI, CARMARTHENSHIRE
SN 7648.
200 ha
Grade i
This is a composite name
for Allt Rhyd-y-Groes and Allt Pen-y-rhiw-
iar and their surrounding upland country (see also U.6). These lie
on a steep north-east-facing valley side overlooking the Afon
Doethie. Silurian rocks, predominantly shales, have weathered to
produce podsols and brown earths of low base-status.
Both woodlands are dominated
by sessile oak, with some particularly
good specimens at Allt Rhyd-y-Groes. The trees in Allt Pen-y-rhiw-
iar are more closely spaced and have been subjected to coppicing in
the past. Associated tree species in both woodlands include ash and
alder on the damper soils with rowan and birch scattered throughout:
wych elm, holly, hawthorn, crab apple and willows (Salix cinerea and
S. auritd) are also present. The shrub layer is not well developed
though hazel is abundant where the oaks have been coppiced.
Blackthorn is marginal and honeysuckle and ivy are restricted to
inaccessible rocks.
The woodland ground flora
is not particularly rich and bryophytes
form an important constituent. On the lower slopes of both woods,
Anthoxanthum odoratum is abundant, replaced by Festuca ovina and
Deschampsia fiexuosa at the upper levels. Other flowering plants
include Vaccinium myrtillus, D. cespitosa, Oxalis acetosella,
Endymion non-scriptus, Geranium robertianum, Filipendula ulmaria and
Chrysosplenium oppositifolium, illustrating the range of soil
conditions. Such ferns as Dryopteris filix-mas and Poly-podium
vulgare are abundant, Hymenophyllum wilsonii and Thelypteris
dryopteris are present. The commonest bryophytes are Polytrichum
spp., Dicranum majus, Rhytidi-adelphus loreus and a cascading stream
has several oceanic bryophytes including jfubula hutchinsiae and
Plagiochila tridenticulata. Bazzania trilobata and Mylia taylori are
also very luxuriant. Nozuellia curvifolia and the rare Sphenolobus
heller anus grow on rotting logs.
W-92. COED
Y CERRIG, MONMOUTHSHIRE
802921.
50 ha
Grade i
This wood lies on rocks
of the Old Red Sandstone series in a
secluded valley within the boundary of the Brecon Beacons National
Park. Two woodland types are present, a hanging wood on steep slopes
giving way to a wet wood on the valley flats. The latter is
dominated by alder, with willows, blackthorn and Rosa spp. in the
shrub layer. Herbs in abundance include Chrysosplenium
oppositifolium, Ranunculus repens, Juncus spp. and Filipendula
ulmaria. Both the north- and south-facing slopes, up to 300 m, are
dominated by sessile oak with some good specimens. Also in the
canopy and locally abundant are ash, elm and silver birch. The
understorey is well developed, with field maple, rowan, crab apple,
holly and hazel. Shrubs such as hawthorn and elder occur, and the
moss Cryphaea heteromalla grows on elder. The wood is apparently
ungrazed and species composition of the ground flora varies from
mesophilous to base-rich types. This includes Anemone nemorosa,
Endymion non-scriptus, Viola spp., Brachypodium sylvaticum, Primula
vulgaris, Mercurialis perennis, Arum maculatum, Orchis mascula,
Silene dioica, Paris quadrifolia, Chrysosplenium alternifolium and
Lysimachia nemorum; patches of Lathraea squamaria are frequent. More
acidic areas with Deschampsia cespitosa, Digitalis purpurea, Galium
hercynicum and Luzula pilosa also occur.
W.93- SALISBURY WOOD: COED
SALSBRI,
MONMOUTHSHIRE
ST 4289.
30 ha
Grade i
Salisbury Wood lies on
the steep slopes and summit of hills composed
of limestone, calcareous shales and calcareous head. Much of the
woodland on the slope is an intimate mixture of small-leaved lime,
ash, wych elm and hazel with much gean, forming high forest derived
from coppice. The
plateau areas have two
types of woodland on partly drained, neutral
clay: ash-gean coppice now grazed by cattle occupies the south-
western arm of the wood, and coppice-with-standards pedunculate oak
over small-leaved lime, ash and hazel occurs round a complex of
parish boundaries and associated pollarded trees. The ground flora
is predominantly calcicolous, with Mercurialis perennis, Galium
odoratum, Brachypodium sylvaticum, Rubus fruticosus agg. and
Phyllitis scolopendrium perhaps the most abundant in a rich mixture
not clearly dominated by any one species.
This wood is selected as
an example of mixed deciduous woodland,
with a particularly rich flora. It has several other important
characteristics. Both oaks and birches are completely absent from
most of the wood. Structurally, the stand has a variety of types
based on the coppice system, one of which, the ash-gean, is very
rare. It lies on a complex of parish boundaries along which are
numerous fine, ancient, pollarded trees. In management and floristic
terms it appears to be closely allied to the eastern mixed deciduous
coppices on calcareous soil, a type which extends along the north
Cotswolds and into south Wales.
W-94- BLACKCLIFF-WYNDCLIFF-PIERCE
WOODS:
CLOGWYN DU-CLOGWYN
GWYN-COED PYRS, MONMOUTHSHIRE
ST 533988-533942.
180 ha
Grade i
This extensive stand lies
on the right bank of the lower Wye and
stretches from Castle Wood in the south to Blackcliff Wood in the
north, and includes those woods on the Live-oaks meander which have
so far been spared destruction by quarrying. The area is composed of
Carboniferous strata, mostly limestone but including a small
proportion of acidic rocks, and includes the two cliffs of
Blackcliff and Wyndcliff and small river cliffs elsewhere,
precipitous slopes along, for example, Piercefield Cliffs, and
gently sloping ground in the centre of Pierce Woods. The woods cover
an altitudinal range greater than 230 m and have a variety of
aspects lacking only west- facing slopes. The woodland is mostly
mature high forest, some of it grown up from coppice-with-standards.
The principal species are beech, yew, small-leaved lime, pedunculate
and sessile oaks, wych elm and ash. Although these are commonly
found in intimate mixtures, one or two species assume dominance
locally. This is particularly evident on the cliff faces and the
scree slopes where beech and yew dominate, and on some of the lower,
gentler slopes where sessile oak and lime are dominant.
Structurally, there is considerable variety including nearly open
scrub on the cliff faces, mixed-age woodland on Piercefield Cliffs
and even-aged, former coppice-with-standards in Martridge Wood. The
subordinate tree and shrub species include a variety of Sorbus spp.
(S. torminalis, S. aria, S. porrigentiformis, S. anglica and S.
rupicola). The ground flora is limited, partly by the heavy shade
but also by the lack of surface water. Floristically, the site has a
number of rare and local species, including Geranium sylvaticum and
large-leaved lime.
These woods represent part
of the range of structural and floristic
variation in the extensive Wye valley woods, particularly the lower
region of limestone. These woods are chosen, rather than the woods
on the left bank from Caswell Wood to Chapelhouse Wood, because they
are less altered by recent forestry operations, include a greater
variety of habitat and woodland types and, on available information,
are floristically the richer.
W.95- WYE
GORGE: HAFAN GWY, MONMOUTHSHIRE-GLOUCESTERSHIRE-
HEREFORDSHIRE
so 5414. 240 ha
Grade i*
These woodlands lie on
either side of a spectacular meandering river
gorge cut through rocks of Old Red Sandstone and Carboniferous
Limestone series. They extend from the area of the Far Hearkening
Rock to Elliotts and Court Woods, and include Lady Park Wood and the
riverside parts of Lords Wood and Mailscot Wood.
Lady Park Wood is mixed
deciduous woodland of an exceptional
character. It lies at the northern end of High-meadow Woods on
slopes and cliffs above the River Wye on Carboniferous strata which
give rise to three major soil types: shallow, stony, limestone
soils, light loams derived from drift of Old Red Sandstone origin
and clay loams derived from shales. This woodland is exceptionally
rich in tree and shrub species, including sessile oak, beech, ash,
small- leaved lime, wych elm, field maple, silver birch, whitebeam,
wild service and the only stand in Britain where large-leaved lime
is an appreciable constituent of the canopy. Much of the Wood has
been cut over in recent decades and now constitutes coppice regrowth
and saplings, but a scattering of mature trees, mainly beech, has
survived. The ground flora varies with soil conditions, with much
Luzula sylvatica on the light loams, Deschampsia cespitosa and Rubus
caesius on the clays, and calcicolous communities with Mercurialis
perennis on the limestone. Numerous rare species have been recorded,
including the tree species Tilia platyphyllos, Sorbus anglica and
the rare hybrid S. torminalis x aria.
On the opposite bank are
the Seven Sisters Rocks. These limestone
pillars are important refugia for certain rare grassland species
including Carex humilis, C. montana, C. digitata and Geranium
sanguineum. In adjacent Lords Wood a number of disused stone mines
are important overwintering sites for greater horseshoe bats.
Coldwell Rocks are north-facing cliffs (75 m) rich in bryophytes and
ferns.
W-96. NANT
IRFON, BRECKNOCK
SN 8454.
40 ha
Grade 2
The Irfon valley is narrow
and steep-sided with extensive outcrops
of Silurian rocks. Two blocks of north-east-facing, hanging sessile
oakwoods spanning an altitude of 290-380 m lie within the boundary
of the NNR. Their primary interest is the presence of breeding
raptors. The site includes woodland on the opposite side of the
valley.
Coed Ty-mawr is a steep
compact area of almost pure, uncoppiced
sessile oakwood. Apart from the northern,
exposed section the trees
are well developed and open grown. It has
a wet oakwood field layer with a rich and varied bryophyte flora,
from Polytrichum and Hypnum species on dry sites through Thuidium
tamariscinum and Dicranella heteromalla, to Sphagnum palustre, S.
papillosum and Fissidens taxifolius on wet sites. Coedydd Hen-Nant &
Digydd is an extended and discontinuous woodland intersected by deep
cwms and is variable in breadth and density. It is predominantly
sessile oak, open, uncoppiced and with well-developed crowns, with
some downy birch, rowan, hazel and ash. Hawthorn and occasional
beech are present. The lush ground cover is similar to Ty-mawr but
there are patches of Pteridium aquilinum or of Agrostis tennis and
other grasses. Wet boggy flushes have Molinia caerulea, Sphagnum
spp., and Carex spp. and there are bryophyte-covered wet, shady
screes.
Coedydd Bron-gynes &
Clawdd-coch lie outside the present Reserve.
These are comparatively dry woodlands on shallow soils facing west-
south-west. They form a low bank intersected by a few shallow cwms.
Coppiced sessile oak is dominant with occasional downy birch and
rowan. The ground flora is variable though grazed. Bracken is
dominant in the more open areas and in other sections mosses,
including Hypnum cupressiforme var. ericetorum, Hylocomium
splendens, Rhytidiadelphus squarrosus, Polytrichum commune, P.
formosum, Mnium hornum and Atrichum undulatum, are most abundant.
The higher levels are grassy with Agrostis tenuis and Anthoxanthum
odoratum. Rock outcrops bear Calluna vulgaris with Festuca ovina and
Polytrichum piliferum.
See also U.g.
W-97- CARN
GAFALLT, BRECKNOCK
SN 9464.
no ha
Grade 2
This complex of woodlands
lies south of Rhayader on the slopes of
Silurian rocks above the rivers Elan and Wye. A discontinuous belt
of oakwood lies around the north-west, west and south flanks of the
hill, Carn Gafallt. The slopes above Elan village are block strewn,
the rock being a hard grit compared to the slates nearby. Variation
in form and size of the trees, due to past management, occurs
throughout. Here the oaks, though short, are spreading and of good
girth. Bryophyte communities are well developed on the blocks,
particularly Scapania gracilis with Lepidozia pinnata, and other
western species present include Bazzania trilobata. Bilberry is
dominant locally but in places there are dense, pure carpets of
moss. A small area of large oak (up to 21 m) with a more uniform
field layer, dominated by bracken, lies to the west of a nearby
stream. The remainder of the woods towards the south also contain
oak of medium size with moss or bilberry-dominated communities.
A woodland with an intimate
mixture of sites and species lies on
gentler slopes to the south side of the Dulas stream, where the rock
is richer in bases and numerous flushes occur. Patches are dominated
by oak, ash, alder or birch or by a mixture of all four species.
Wych elm is scattered throughout, hazel and hawthorn are plentiful,
and rowan and holly are also present. Parts of the wood have a block-
strewn
floor and elsewhere a rich field layer on mull soils passes
in places to flush mire under alderwood.
Some of the woodlands in
this complex are perhaps as good as
existing Reserves but since they duplicate the interest of these and
there are no unusual associated features, a status higher than grade
2 is not considered to be justified. (See Appendix.)
The valley bottom has old
pastures and hay meadows (with Sanguisorba
offidnalis abundant, Carex hostiana, Equisetum sylvaticum,
Platanthera chlorantha, Vicia cracca and V. orobus locally common),
Juncus marsh (with Eleo-charispalustris, Scutellaria galericulata,
Sparganiumramosum and Triglochin palustris) and wet heathy fields
with some developing Sphagnum bog (with Vaccinium oxycoccus, Drosera
rotundifolia, Wahlenbergia hederacea and in drier parts Genista
anglica, G. tinctoria and Cirsium dissectum).
W.gS. BLAENAU NEDD &
MELLTE, BRECKNOCK
SN 9210.
60 ha
Grade 2
These woodlands are situated
in the upper gorges of the Neath River
to the north of the South Wales coalfield, and within the Brecon
Beacons National Park. Outcrops of Carboniferous Limestone occur
only on the higher parts of the gorge sides and its influence is
localised; the river itself cuts through Millstone Grit. The
composition of the woodland in these gorges varies from a grazed
acidophilous sessile facies; through a more mixed deciduous type
with ash, wych elm and a little small-leaved lime in the canopy with
hazel, field maple and some hawthorn below; to the stream sides
dominated by birch and alder. Small areas of mesophilous vegetation
occur, though, in the main, a grazed acidophilous field layer is
present. Deschampsia flexuosa is the main constituent with a ground
layer of Dicranum majus, Leucobryum glaucum, Polytrichumformosum,
Mnium hornum and Diplophyllum albicans. Luzula sylvatica and
Vaccinium myrtillus are only present on inaccessible rock outcrops.
The splash areas of the waterfalls and trees and rocks in the gorges
have ferns and bryophytes, rare or local in south Wales, including
Hymenophyllum tunbrigense, H. wilsonii, Ptilidium pulcherrimum and
Isopterygium pulchellum.
W-99- DARKEN FACH,
BRECKNOCK
so oiio.
12 ha
Grade 2
This west-facing site lies
across the upper Taff valley, a short
distance upstream from Penmoelallt, and can be considered an
alternative to it. It consists of an open scrub on low limestone
cliffs with screes and woodland on the gentler slopes. The latter
are dominated by ash inter-mixed with wych elm together with a well-
developed understorey of hazel and hawthorn. Field maple is present
and a group of small-leaved lime lies at the northern end. The
primary interest lies in a concentration of Sorbus spp. on the
southern end of the Barren Fach crags. Several shrubs of S. leyana
together with a specimen of S. porrigentiformis grow just below the
crags together with ash, yew and holly.
The ground layer is heavily
grazed and includes Mer-curialis
perennis, Oxalis acetosella, Rubus fruticosus agg.,
Deschampsia cespitosa,
Phyllitis scolopendrium with some Asperula
odorata.
W.IOO. GLANNAU,
RADNOR
SN 9065.
25 ha
Grade 2
This site on Silurian shales
and sandstones occurs on the steep
slopes above the Garreg-ddu reservoir which bounds it on the east
and south. The soils vary in base content and though dominated by
sessile oak, three distinct blocks occur. On basic soils at the
northern end a dense mixture of wych elm, oak, hazel, willow and
birch grows over abundant Mercurialis perennis with Circaea
lutetiana and Geranium robertianum. Outcrops of rocks support
Asplenium tri-chomanes, Neckera crispa, Tortella tortuosa, Bartramia
halleriana, Brachythecium plumosum and Ctenidium mollus-cum
indicating their moderate lime content. The central area contains a
less dense growth of oaks, 15-18 m in height, with a few birch and
rowan over a bracken- dominated floor with patches of moss-rich
grassland with Deschampsia flexuosa, Digitalis purpurea, Galium
hercynicum and Oxalis acetosella. Nowellia and Lepidozia reptans
cover fallen, rotting tree trunks. At the south end, sycamore and
beech increase in abundance with a scattering of conifers. Sacco-
gyna viticulosa and Plagiochila spinulosa are abundant here and
other species include Athyrium filix- femina, Dryopteris filix-mas,
Blechnum spicant and Deschampsia cespitosa.
W.IOI. COED
ABER EDW, RADNOR
so 0847.
16 ha
Grade 2
This wood lies to the south
of the River Edw. The steep north-facing
slopes of the valley carry both oakwood and mixed deciduous wood;
the former occurring on acidic and the latter on the calcareous
shaly beds of the Ludlow Group of the Silurian. Where the calcareous
rock outcrops the main trees are ash, wych elm and hazel but there
are some field maple and rowan and a few trees of small-leaved lime.
There is also some elder and gooseberry but birch is scarce. The
ground flora although sparse is species-rich and includes
Polystichum setiferum, Asplenium trichomanes, Phyllitis
scolopendrium, Melica uniflora, Brachypodium sylvaticum, Poa
nemoralis, Saxifraga hypnoides, Mycelis muralis, Mercurialis
perennis, Chrysosplenium oppositifolium, Glechoma hederacea,
Veronica montana, Hedera helix, Geranium robertianum, G. lucidum,
Anomodon viticulosus, Thamnium alopecurum, Neckera crispa, N.
complanata, Camptothecium sericeum, Brachythecium rutabulum, B.
plumosum, Eurhynchium praelongum, Mnium rostratum, M. undulatum,
Metzgeria furcata, Plagiochila asplenioides and var. major,
Madotheca platyphylla, Marchesinia mackaii.
In other areas oak is dominant
and this dominance is clearly
associated with scarcity of lime in the parent rock which in turn
seems to depend on the disappearance of the calcite veins. The flora
of these acidic rocks is poor and includes the common woodland
bryophytes. There is a local abundance of Vaccinium myrtillus and
grasses such as Holcus mollis, Anthoxanthum, Festuca ovina and
Deschampsia flexuosa.
Presence of small amounts
of lime in the generally acidic rocks is
marked by an increase in richness of the ground flora although oak
remains dominant.
W.I02. COOMBE WOODS: COED
Y CWM,
MONMOUTHSHIRE
ST 4593.
35 ha
Grade 2
This complex of woods lies
on a narrow, steep-sided valley of the
Cas- Troggi brook where it cuts through Carboniferous Limestone.
It includes Coombe Wood itself, Common Wood on the opposite side of
the valley, those parts of Llanmelin Wood which have not been
replanted with conifers, and other woodlands which form a contiguous
group. Almost all the woodland lies on steeply sloping ground with
strongly calcareous soil in a matrix with limestone fragments, but
small areas occupy gently sloping ground in both the plateau and
valley-bottom situations, where the soil is heavier, less stony,
less well drained and locally with impeded drainage, but still
calcareous. The woodland is mixed deciduous with beech, ash, wych
elm, small-leaved lime, pedunculate oak, field maple and hazel the
most abundant, but with many other species present, including
whitebeam. Over large areas the ground flora is dominated by dog's
mercury, mixed with Allium ursinum at the base of the slopes, but
there is a good deal of variation from this, with areas of
Convallaria majalis.
Coombe Woods is best regarded
as an alternative to the Blackcliff-
Wyndcliff-Pierce Woods grade i site (W.Q4). It is similar in that
much of the woodland is mature high forest derived from coppice; in
the intimate mixture of the most abundant species, with only small
areas of single-species dominance; and in possessing a hill fort
occupied by similar mixed deciduous woodland. |
|
W.IO3- COEDYDD DYFFRYN
CONWY, CAERNARVONSHIRE
(a) Coed Dolgarrog SH 7666.
70 ha
Grade i
This wood extends for about
1.6 km along the steep western side of
the Dyffryn Conwy and is bounded to the north and south by deep
rocky ravines formed by streams whose flow is now somewhat reduced
by the Dolgarrog Hydro-electric Scheme. The wood has a large
altitudinal range from 30 m to over 300 m but, apart from the upper
margin, is sheltered from the prevailing south-west winds. Rainfall
is about 150 cm annually, but humidity is lower than in the
adjoining gorge woodlands, such as Ceunant Dulyn. The rocks are
Ordovician rhyolites and rhyolite tuffs in the south, followed in a
northerly direction by a massive buttress of pumice tuff projecting
into the main valley, then a concave slope of slate and finally, in
the extreme north, a second but smaller buttress of pumice tuff. The
pumice tuff yields soils of moderate base-status, as in Ceunant
Dulyn, whilst the other rocks yield more acid soils. The underlying
rocks are often masked by layers or pockets of drift particularly on
the upper slopes and mixed colluvium on the lower slopes.
The dominant tree is oak,
of both species as well as hybrids, though
in contrast to Coed Gorswen there is a preponderance of sessile
types; there is no marked association here between soil type and
species of oak. However, this wood is best included in the mixed
deciduous category, for there are numerous other tree species,
either as scattered individuals or locally dominant. They include
birch, wych elm, ash, alder, sycamore, rowan, holly, small-leaved
lime and crab apple. Beech is occasional throughout the wood and a
few conifers, Scots pine, Norway spruce and larch, are also present.
On the more base-rich soils the flora is characterised by such
species as Brachypodium sylvaticum, Mercurialis perennis, Circaea
lutetiana, Sanicula europaea, Fragaria vesca, Allium ursinum,
Geranium robertianum, Mycelis muralis, Viola riviniana, Dryopteris
filix-mas, Polystichum setiferum, Rubus fruticosus and Car ex
sylvatica. The more acidic soils are dominated by such species as
Agrostis tennis, Pteridium aquilinum, Festuca rubra, Des-champsia
flexuosa, Anthoxanthum odoratum, Galium her-cynicum, Oxalis
acetosella, Digitalis purpurea and Vaccinium myrtittus along with a
range of bryophytes. Bryophytes are not conspicuous throughout most
of the woods but the two ravines and some of the older trees provide
a useful range of habitats. Hylocomium brevirostre is abundant in
the west of the area. The wood includes a wide range of habitats for
larger mammals and birds and is notable in having a large population
of badgers.
In the south the wood extends
high up the valley of the Afon Ddu
which contains the Ardda Alder Wood. This is a high-level alderwood
at 210-260 m, a type previously common but now extremely rare in
Wales. This was part of the Cistercian monastery of Aberconwy
established in the twelfth century. The survival of the alder
woodland may be because of the more limited extent of sixteenth-
century enclosures in this area compared to similar valleys in
Snowdonia. The shrub layer is well developed in some parts of the
wood but almost completely absent from others, the main species
being hazel but holly and rowan are also common. Spindle occurs but
is rare. The ground flora of the alderwood is extremely varied.
(b) Coed Gorswen SH 7570.
14 ha
The wood lies on the western
side of the more gently sloping lower
Dyffryn Conwy at an altitude of 45-150 m. It is the driest of the
base-rich series with a rainfall of about 130 cm annually. The
underlying rocks are completely masked by glacial drift and
colluvium of mixed composition containing acid sedimentary, acidic
and basic igneous rocks, resulting in a mixture of acidic and base-
rich soils. Several streams and flush lines run through the wood
adding further to the base-rich influence. The result is a diverse
wood consisting of oak, wych elm, alder, ash, sycamore, both birches
and gean. Both sessile and pedunculate oaks and hybrids are present
in the wood but pedunculate types are probably in the majority.
There seems to be a characteristic distribution with pedunculate
types on wetter flushed sites and sessile types on the more freely
draining soils, particularly at the higher west side of the wood.
There is a well- developed shrub layer, and blackthorn are locally
dominant. Other species present include rowan, hawthorn, elder, crab
apple and field maple. The ground flora is equally rich and five
main communities have been described. On freely and imperfectly
drained soils the main species are Oxalis acetosella, Geranium
robertianum, Rubus fruticosus, Viola riviniana, Veronica chamaedrys,
Brachypodium sylvaticum, Geum urbanum, Sanicula europaea and Circaea
lutetiana. Less common plants include Botrychium lunaria and
Epipactis helleborine. On the wetter gleyed soils, in flushes or
beside streams the main species are Ranunculus repens, R. flammula,
Chrysosplenium oppositifolium, Mentha aquatica, Phalaris
arundinacea, Carex remota, C. laevigata, C. nigra, Juncus effusus
and J. acutifiorus.
(c) Ceunant Dulyn
SH 7568.
16 ha.
This site is situated in
the steep-sided valley of Afon Dulyn which
flows east into the River Conwy. The altitude ranges from 75-240 m.
Rainfall is about 152 cm annually but with high humidity within the
ravine. Flow in the river is affected by the Dolgarrog Hydro-
electric Scheme. The underlying rocks are Ordovician sediments and
pumice tuff which have produced acid and moderately base-rich soils
respectively. The acidic soils support oak (mainly Quercus petraea]
and birch woodland with a sparse shrub layer and a ground flora
consisting of such species as Pteridium aquilinum, Agrostis tennis,
Deschampsia flexuosa and Oxalis acetosella. On the more basic soils
the main species is again oak, but this time Q. petraea, Q. robur
and hybrids, along with ash, wych elm, alder and sycamore. There is
a well- developed shrub layer consisting mainly of hazel and a much
richer ground flora including such species as Ranunculus repens,
Carex remota, Angelica sylvestris, Sanicula europaea, Mercurialis
perennis, Brachypodium sylvaticum, Deschampsia cespitosa, Oxalis
acetosella, Viola riviniana, Geranium robertianum, Dryopteris filix-
mas and Rubus fruticosus agg. The Atlantic bryophyte flora is only
moderately rich.
W.I04- COEDYDD ABER, CAERNARVONSHIRE
SH 6671.
165 ha
Grade i
These woods form a somewhat
dissected complex along the valley of
Afon Aber, and contain at least four distinct types. In altitude
they range from 30 to 210 m, and at the north end of the valley
rainfall is only 114 cm annually. The parent rocks are Ordovician
and Cambrian grits and shales, and the lower slopes are drift
covered. The woods on the upper parts of the system on both east and
west sides have typical dry oakwood of sessile oak with some birch
and rowan on acidic skeletal brown earths, but these grade below
into mixed deciduous woodland of ash, wych elm, oak, birch and
abundant hazel on base-rich clayey soils, on both steep slopes
bounding a central ravine and flatter ground to the north and south.
The oakwood has a typically
acidophilous field layer with Agrostis-
Anthoxanthum grassland, a good deal of bracken locally, and a well-
developed moss layer in which Atlantic species are not particularly
well represented, probably because there are few blocks and also
because of unfavourable management. The mixed woodland has the
richer Brachypodium sylvaticum herb-rich grassland, with an
abundance of basiphilous species. On the steep slopes flanking the
ravine, the fern Polystichum setiferum is abundant, while the rock
ledges have a fine colony of the very local grass Festuca altissima,
and Hypericum androsaemum also grows here.
On flatter, waterlogged
ground there are patches of alderwood with a
swampy floor containing fairly hydrophilous species such as
Ranunculus repens and Chrysosplenium oppositifolium. Where the wood
thins out at the head of the valley, there is a transition to a
fairly extensive area of open hawthorn scrub with some crab apple in
a grassland community containing a great abundance of bluebell. This
passes into the precipitous northern cliffs down which pour the Aber
Falls, and the lower and more broken faces here have interesting
examples of ungrazed cliff woodland with stunted oak, birch and
rowan, and a luxuriant field layer of Luzula sylvatica (illustrating
the sensitivity of this species to grazing). Atlantic bryophytes are
well represented on these cliffs near the falls and include very
local species such as Adelanthus decipiens, Anastrepta orcadensis,
Eazzania tricrenata and Hylocomium umbratum.
The lichen epiphyte flora
is one of the most interesting in north
Wales. It is essentially lowland in character, consisting of a rich
Lobarion community in the ravine with Parmeliella plumbea in its
only certain recent north Welsh locality in local abundance. Great
rarities here are Arthonia cinere-opruinosa (four British
localities), on an old dry bank, Polyblastia allobata, Gyalidiopsis
sp. (undescribed and new to science) and Mycoblastus fuscatus.
Perhaps the most important
feature of Coedydd Aber is the diversity
of woodland types within a single complex, reflecting differences in
soil conditions and management. The site is contiguous with the
Carneddau part of the Eryri upland site (U.io), and can be regarded
as a habitat extension of the latter. Coedydd Aber also has a
particularly varied bird fauna, with strong breeding populations of
wood warbler, pied flycatcher and redstart.
W.I05. COED
TREMADOG, CAERNARVONSHIRE
SH 5640.
24 ha
Grade i
This woodland lies on cliff
and scree at 15-150 m on the south-
facing scarps of the Moel Hebog massif, overlooking the reclaimed
estuary of the Afon Glaslyn (the Traeth Mawr). The site is strongly
exposed to south-west onshore winds but the rainfall is lower (about
152 cm annually) than for many of the Snowdonian woodlands, and the
aspect is sunny. The underlying rocks are Ordovician slates but
there are several large intrusions of base-rich dolerite which form
high, vertical cliffs. The steep slopes below the cliffs have a
great deal of scree, varying from huge tumbled blocks in the east to
much smaller material at the west end. Soils are mostly thin and
skeletal, and vary from acidic to strongly basic, with fertile brown
earths where there is flushing from the dolerite.
The vegetation varies from
closed woodland to open cliff and scree
communities. The closed woodland varies from an acidophilous type
dominated by sessile oak, with some pedunculate oak, to a
basiphilous ash-hazel type. Beech and sycamore are locally
plentiful. The oakwood has rowan and holly in the shrub layer, and
field communities have Deschampsia flexuosa, Vaccinium myrtillus,
Anthoxan-ihum odoratum, Agrostis tenuis, Teucrium scorodonia and
Pteridium aquilinum. The ashwood has a field layer with grasses such
as Brachypodium sylvaticum and Melica uni-flora, and forbs such as
Mercurialis perennis, Geum rivale, Epilobium montanum, Melandrium
rubrum and Veronica offkinalis.
The woodland shows all
degrees of opening out, to scattered growths
of trees on the screes, and in places a scrubby oakwood spreads up
the less precipitous cliffs. There is a variable development of tall
scrub, mainly of hazel and hawthorn, with lesser amounts of privet
and blackthorn. The screes locally have dense masses of bramble and
there is a good deal of ivy. The flora of the more open habitats is
rich and interesting, with a variety of moderately to strongly
basiphilous species, including Sedumforsteranum, S. telephium,
Origanum vulgare, Hypericum androsaemum, H. hirsutum, Geranium
lucidum, G. robertianum, Chrysanthemum leucanthemum, Polystichum
setiferum, Phyllitis scolo-pendrium, Asplenium trichomanes, A.
adiantum-nigrum, Pterogonium gracile and Marchesinia mackaii. More
acidophilous or acid-tolerant species of rocky habitats include
Sedum anglicum, Teucrium scorodonia, Hypochoeris radicata, Cotyledon
umbilicus, Corydalis claviculata, Dryopteris filix-mas, Polypodium
vulgare and Hedwigia integrifolia.
The interest of the site
is thus partly for the range of woodland
features, but also for the more open scrub and rock communities
which are referable to types discussed under Lowland Grasslands,
Heaths and Scrub.
W.IO6. COED
DINORWIG, CAERNARVONSHIRE
SH 5860.
50 ha
Grade i
This wood is unusual in
being an ungrazed upland sessile oakwood;
fenced off from sheep by the farms above and the Dinorwig quarries
to the south-east. The oaks are mostly rather small and many are
grown over with ivy; there is a patchy underscrub of hazel and
holly. The field communities are the most interesting feature, with
dominance of Luzula sylvatica in the upper part, and a good deal of
bilberry and bramble elsewhere. Field communities of this kind are
characteristic of ungrazed hill woods on acidic to mildly basic
soils, and are well represented in the oakwoods of the Loch Lomond
islands (W.i69), and some ravine woods. They are, however, rare in
the hill woods of Wales. There are block screes and rock outcrops
with some Atlantic plants, including Hymenophyllum wilsonii, Plagio-
chila spinulosa and Scapania gracilis. At the upper fringe, the wood
grades into tall Callunetum on rocky bluffs, and there is a
transition zone with small, stunted oaks, which are almost certainly
the result of coppicing or other human disturbance.
W.ioy. COEDYDD DYFFRYN
MAENTWROG,
MERIONETH Grade i*
a) Coed Camlyn-Ceunant
Llennyrch SH 6539. 119 ha
Coed Camlyn is situated
on steep slopes on the south side of the
Ffestiniog Valley, and the main section of the wood has a north-west
aspect, but other parts face north and southwest. Altitude ranges
from 15-150 m and exposure to wind, particularly on the upper
slopes, is severe, the south-west winds having a more or less clear
run from the sea about 8 km distant. Rainfall is about 180 cm
annually. The underlying rocks are Upper Cambrian and consist mainly
of acidic slates. These rocks are exposed in cliffs at the top of
the slopes, whilst the lower slopes are mainly covered with scree of
periglacial origin on which freely draining acidic skeletal soils
are formed. In the main wood the tree layer is dominated by sessile
oak whilst birch is locally co-dominant or forms an understorey in
some more open areas. Holly, beech and sycamore are also present.
There is a small outlying area dominated by birch and in another
sweet chestnut is common. The southern end of the wood has few tall
shrubs and the ground flora is almost completely dominated by
bilberry, with Deschampsia flexuosa and Molinia caerulea
subdominant. Bracken dominates the field layer in more open areas.
In the north bilberry is less prominent, there is a sparse
understorey of hazel and the ground flora is dominated by Agrostis
spp., Deschampsia flexuosa, Oxalis acetosella and bryophytes. There
were formerly several groups of conifers in the wood but these have
recently been removed. Rhododendron ponticum is present in parts of
the wood, but its spread is now largely under control.
At its south-west end,
Coed Camlyn bends round into the deep wooded
glen of Ceunant Llennyrch which carries the stream from the
Trawsfynydd reservoir and contains one of the finest river gorges in
north Wales. The rocks are mainly Cambrian slates and shales, but
there are basic intrusions, and soil conditions vary from acidic to
basic, giving the usual variation from sessile oak to mixed
deciduous woodland. In places here, however, the oakwood has been
replaced by serai birch. On the precipitous sides of the gorge,
woodland species (e.g. Luzula sylvatica and numerous forbs) which
suffer from sheep- grazing are able to flourish, but the most
outstanding feature of the glen is the extremely rich Atlantic
cryptogamic flora. The two ferns Dryopteris aemula and Hymenophyllum
tunbrigense probably grow more abundantly here than anywhere else in
Wales, and Osmunda regalis occurs more sparingly. The bryophyte
flora compares favourably with that of Coed Ganllwyd and includes
species such as Sematophyllum demissum, Hylocomium umbratum, Hypnum.
callichroum, Adelanthus decipiens, Colura calyp-trifolia,
Drepanolejeunea hamatifolia, Harpalejeunea ovata, Radula valuta and
Marchesinia mackaii.
The gorge and its flora
provide a complement to the hanging woods of
Coed Camlyn, which do not have a block-strewn floor and have only
the commoner species of Atlantic bryophytes. The construction of the
Trawsfynydd reservoir has greatly reduced the flows of the stream
through Ceunant Llennyrch, but this
has apparently had no
significant effect on atmospheric humidity and the richness of the
hygrophilous flora.
The lichen flora shows
a fine development of the lowland Lobarion
community on the large sheltered oaks at the lowest part of the
valley, with least rainfall and richest soil. Rinodina isidioides
and Pannaria sampaiana are particularly noteworthy here; the latter
species, recently described from Iberia, proves to be rare though
widely scattered in western Britain from the New Forest and Devon
through north Wales to western Scotland. Other rarities include
Thelopsis rubella and Parmelia horrescens.
Although the upper part
of the valley has a magnificent bryophyte
flora, the lichen vegetation is represented by the species-poor
Parmelietum laevigatae. However, there occurs an undescribed Bacidia
sp. with an isidiate thallus which is known to be widespread but
rare in old southern and western forest fragments.
Thelotrema lepadinum, a
lichen which seems to be a very good
indicator of ancient forest relict sites, also occurs, as does
Haematomma elatinum and Lecidea cinnabarinum of similar occurrence.
The site is particularly
important lichenologically because in this
one forested valley there exists both the lowland type of oakwood
and its typical lichen flora, and also the upland types with the
zone of transition.
(b) Coedydd Maentwrog-Coed
Cymerau
SH 6741, SH 6742, SH 6841,
SH 6842. 147 ha
These lie on the north
side of the Vale of Ffestiniog, Coed Cymerau
occupying the steep slopes of the Afon Goedol ravine, whilst Coedydd
Maentwrog extends 2.4 km along the main valley. At Coed Cymerau
altitude ranges from 45-150 m and apart from the upper slopes on the
east side of the river the wood is very sheltered. Rainfall is 200
cm annually but within the confines of the narrow valley atmospheric
humidity is markedly higher than in surrounding areas. There is a
rather shallow gorge with a small waterfall near which Hymenophyllum
tunbrigense grows. The underlying rocks are Cambrian slates which
weather to produce an acidic soil. On the west side of the river
much of the soil is little more than stabilised scree originating
from a line of cliffs above. In the east the soil is deeper in
places and may be partly formed on drift but throughout the wood as
a whole there are numerous areas of exposed rock or tumbled detached
boulders.
The tree layer is dominated
by oak Quercus petraea with only a small
contribution of Q. robur types. Birch is a scattered co-dominant and
becomes locally dominant. Rowan is also common usually as a
subdominant and there are a few widely scattered individuals of ash,
sycamore, alder, holly and crab apple. Throughout most of the wood
the shrub layer is poorly developed but in some slightly flushed
areas particularly in the north and west, there is a moderate
density of hazel. Molinia caerulea, Deschampsia flexuosa and
Agrostis tennis are the three main ground flora dominants under
closed canopy. In open areas bracken takes over. In contrast to Coed
Camlyn, bilberry has a fairly minor role here. Other common
herbaceous species include Melampymm pratense, Oxalis acetosella,
Galium hercynicum and Potentilla erecta. Bryophytes dominate large
areas of the wood particularly in the more rocky areas and a wide
range of species has been recorded including several rare Atlantic
species, though this site is less rich than some other Merioneth
woodlands. Other habitats represented within the wood include
several small acidic mires (with Sphagnum imbricatuni), grassland
(with Wahlenbergia hederacea) and a small area of open partly
stabilised scree on the west side. The river traversing this glen is
heavily polluted by sewage from Blaenau Ffestiniog.
Coedydd Maentwrog has an
altitude range of 15-150 m. There is also a
small detached area a few hundred metres from the west end of the
main wood running down to Llyn Mair. The main aspect of the wood is
south and it is therefore sun exposed. Rainfall is about 180 cm
annually, but there is not the high atmospheric humidity associated
with the ravine at Cymerau. This wood is also considerably less
humid than the north-west-facing slopes of Coed Camlyn which receive
little direct sunshine. The underlying rock is Upper Cambrian shale.
As at Camlyn these have been frost shattered to produce extensive
periglacial screes upon which acidic soils have developed, but rock
weathering at Maentwrog has produced a higher proportion of finer
fractions in the soil which is generally richer and more retentive
than at Camlyn. The dominant species in the tree layer is sessile
oak but there are a number of trees with pedunculate characters
indicating some hybridisation. Birch is also common either as a
scattered co-dominant or a local dominant round clearings. Other
species present include rowan, ash, alder and sycamore. The shrub
layer is poorly developed with only scattered hazel, and, though
Rhododendron ponticum is common in the west end of the wood, its
spread is under control. The ground flora beneath the tree canopy is
dominated mainly by grasses (Anthoxan-thum odoratum, Agrostis spp.,
and Deschampsia flexuosa) and mosses. The wood has been more
disturbed in recent times than its neighbours, and large gaps are
dominated by dense bracken. The oak trees of Coedydd Maentwrog have
a much wider age distribution than the other woods in the Ffestiniog
Valley (100-200 years) compared with 100-150 at Cymerau and about
100- 120 at Camlyn. The different ages, however, tend to be in
groups rather than intimately mixed as in some parts of Cymerau.
(c) Coed y Rhygen SH 6836.
27 ha
The wood lies on the western
side of Trawsfynydd Lake at an altitude
of 200-260 m. Rainfall is about 200 cm annually, and the proximity
of the lake may add to the local atmospheric humidity. Topography
within the wood is extremely broken with ridges of rock running up
the slope, and there are numerous small cliffs, slabs and block
litters. The area lies at the north edge of the Harlech Dome and the
underlying rocks are mainly hard Cambrian grits, acidic and
resistant to weathering. Except at the north-west end of the wood
where there is a deeper acidic soil on drift material, the soils are
extremely shallow and skeletal (on the rock ridges) or wet and peaty
(in the hollows between). The main species in the tree layer are
sessile oak and birch. The most common composition is large, old oak
trees set in a matrix of birch but, at the east end of the wood,
birch is dominant and there has probably been selective removal of
oak over a long period. Rowan is common and scattered throughout the
wood and there are a few willows in the wet hollows. The shrub layer
is poorly developed, being limited to a few patches of hazel in
areas of slight enrichment. The ground flora is generally bryophyte-
dominated although Deschamp-sia flexuosa is common throughout and
both bracken and bilberry may attain local dominance. Local
enrichment of soil is indicated by the local presence in the field
layer of Mercurialis perennis, Geranium robertianum, Lysimachia
nemorum and Filipendula ulmaria. The characteristic woodland mosses
such as Rhytidiadelphus loreus are in profusion in rocky places but
over 100 other bryophytes occur. Many species grow with a luxuriance
only equalled in western Scotland, notably Plagiochila spinulosa,
Scapania gracilis, Lepidozia pinnata, Bazzania trilobata and
Saccogyna viticulosa. Hymenophyllum wilsonii is common amongst the
rocks and the older trees are covered with epiphytic species
including P. punctata. Rarer bryophytes are also present and these
include Sematophyllum demissum, Hypnum calli- chroum, Hylocomium
umbratum, Thuidium delicatulum, Adelanthus decipiens, Harpanthus
scutatus, Plagiochila tridenticulata, B. tricrenata and Lepidozia
pearsonii. The richness of the bryophyte flora points to Post-
glacial continuity of tree cover at the site.
The epiphytic lichen flora
is limited to the Parmelietum laevigatae
community on highly leached acidic bark with only traces of the
Lobarion community (Pannaria pityrea, Parmeliella corallinioides,
Sticta sylvatica, Dimerella luted) on a few more sheltered old
trees. The epiflora, in fact, comprises only 39 species of lichens,
a remarkably low number.
Indicators of ancient,
relic woodland present are Thelo-trema
lepadinum, Haematomma elatinum, Lecidea cinna-barinum, and probably
the Lobarion spp. mentioned. Of oceanic species, the wood possesses
Menegazzia terebrata and Cetrelia cetrarioides as well as the common
Parmelia laevigata, Mycoblastus sanguinarius, Sphaerophorus spp. and
Ochrolechia tartarea of the Parmelietum laevigatae.
The rock flora is interesting
and typical of highly leached acid
environments with several Cladonia spp. and the oceanic Akctoria
bicolor.
The larger peaty areas
between the rock ridges often have no trees
on them and are wet grass-heaths or even soligenous mires dominated
by such species as Myrica gale, Molinia caerulea and Erica tetralix.
(d) Ceunant Cynfal SH 7041.
10 ha
This wooded ravine below
Ffestiniog is one of the finest river
gorges in the whole of Britain. The Afon Cynfal has cut across the
dip of acidic and mildly basic Cambrian slates to a depth of 30-45
m, and much of the gorge is
flanked by sheer cliffs
and interrupted by several considerable
waterfalls. As such the area is of outstanding geo-morphological
interest.
The variety of rock types
results in a mosaic of oakwood communities
on the acidic sites and mixed deciduous woodland on the richer
soils. The oakwood along the top of the gorge is an excellent
Quercus petraea wood, with some birch, rowan and holly. The ground
flora is grazed in parts and it is therefore predominantly grassy,
except in steep, ungrazed situations where there is an abundance of
Luzula sylvatica and Vaccinium myrtittus. Seepage areas within the
wood are characterised by banks of Chrysosplenium oppositifolium,
growing with Trichocolea tomentella.
Bryophytes are abundant
in the wood in a variety of habitats, for
example on the woodland floor, on blocks, on rotten logs, and as
epiphytes. Atlantic species are particularly well represented with
Dicranum scottianum, Hylocomium umbratum, Lepidozia pinnata, and L.
pearsonii, and the filmy ferns Hymenophyllum wilsonii and H.
tunbrigense. Epiphytic lichens are abundant with Lobaria spp.,
Sticta spp., and Parmeliella atlantica. Several notable bryophytes
have been found in the gorge including Jubula hutchinsiae, Metzgeria
hamata, Isothecium holtii, Tetraphis browniana, Drepanolejeunea
hamatifolia, Grimmia hartmanii, and Harpalejeunea ovata.
The small side-stream flowing
into the Afon Cynfal from Ffestiniog
carries much sewage and seriously pollutes the lower kilometre of
the river in the glen, but the better upper section is unaffected.
There is a general similarity to the gorge of Ceunant Llennyrch, but
many differences in detail, and the Afon Cynfal, unlike the other
stream, is undiminished in flow through damming higher up.
(e) Ceunant Llechrwd, Gellilydan
SH 6840.
7 ha
Below the hamlet of Gellilydan
and between the wooded glens of
Ceunant Llennyrch and Ceunant Cynfal, a third north-west-flowing
stream which feeds the Vale of Maent-wrog has cut a deep ravine.
This glen also is wooded, mainly with sessile oakwood, but contains
fragments of mixed deciduous growth. A number of Atlantic bryophytes
are represented and there is a small colony of Osmunda regalis. On
the whole, however, this glen is less rich floristically and less
spectacular in the depth and abruptness of its gorge than the other
two mentioned. It is, however, an integral part of the Coedydd
Dyffryn Maentwrog complex and was once continuous with the woods of
the other adjacent sites.
W.IOS. COED
GANLLWYD, MERIONETH
SH 7224.
25 ha
Grade i*
The wood occupies a comparatively
gentle slope on the east side of
the Rhinog Mountains at 60-140 m, and is traversed along its north
side by the rocky gorge of the Afon Gamlan with its well-known
waterfall Rhaiadr-ddu. The local rainfall is about 190 cm annually
and the atmospheric humidity is accentuated by the sheltered nature
of the site and by river spray immediately around the falls. The
underlying rocks are Cambrian grits, acidic, hard and resistant to
weathering, but there are also several intrusions of base-rich
dolerite outcropping in the wood. Several smaller streams run
through the mid and southern sections of the wood and there are
significant areas of flushing from the base-rich rocks, giving a
mixture of acidic and basic soils.
The tree layer is dominated
by oak (mainly Quercus petraea but some
Q. robur types are present) with distinctive strips of ash along the
various streams. Birch and sycamore are widely scattered throughout
the wood and alder is locally dominant in wet places. Other species
present include wych elm, beech, rowan and gean. Development of the
shrub layer is poor, the most common species being hazel, but holly,
hawthorn, blackthorn and alder buckthorn are all present in small
quantities. Bracken dominates large areas of the ground flora whilst
in other more shaded areas bryophytes are abundant in both number
and species. In a few areas there is a true herb layer and on drier
acidic soils Agrostis sp., Anthoxanthum odoratum, Festuca ovina,
Galium hercynicum, Endymion non-scriptus, Digitalis purpurea,
Potentilla erecta and Melampyrum pratense are common, whilst flushed
sites contain such species as Circaea lutetiana, Mercurialis
perennis, Brachypodium sylvaticum, Geranium robertianum, Geum
urbanum and Prunella vulgaris. Small acidic soligenous mires occur
which contain Sphagnum imbricatum.
The wood is famous for
the presence of a wide variety of rare
oceanic ferns, liverworts and mosses. Parts of the wood are strewn
with boulders of coarse grit and it is in and around these that
bryophyte communities are best developed, and in the actual gorge.
On the shady and/or wet rocks beside the waterfalls and streamlets
are species such as Campylopus setifolius, Leptodontium
recurvifolium, Hyloco- mium umbratum, Colura calyptrifolia, Jubula
hutchinsiae, Drepanolejeunea hamatifolia, Harpalejeunea ovata,
Radula valuta, R. aquilegia, Frullania microphylla, Plagiochila tri-
denticulata and the ferns Hymenophyllum wilsonii, H. tunbrigense and
Dryopteris aemula. On slabs and rocks in the woods and beside the
stream there is a great abundance of the rare Sematophyllum
demissum, and S. novae- caesareae is recorded. Adelanthus decipiens
is locally abundant and Mylia cuneifolia has been found here in its
only station outside Scotland. Such species require warm humid
conditions and most are found in and around the main gorge of the
Afon Gamlan and its tributary streams. The presence of so large an
assemblage of rare and local Atlantic bryophytes is believed to
indicate continuity of at least some woody cover throughout the Post-
glacial Period. Although there is evidence that the present oaks
were planted together during the nineteenth century, it is
inconceivable that so many drought- sensitive species could have
survived if the whole area had been totally cleared of woodland or
scrub at any one time.
The area also contains
important geological features including one
of the few localities on the Harlech Dome yielding Middle Cambrian
fossils.
W.IOQ. COED CRAFNANT, MERIONETH
SH 6128.
35 ha
Grade i*
This wood is about 1.6
km in length and occupies a northwest-facing
terraced slope on the south-east side of the Afon Artro valley on
the western flanks of the Rhinog massif (U.I2). The wood extends
from 76 to over 210 m altitude. The high annual rainfall (200 cm),
the shaded aspect, the prevalence of moist sea winds and mist, and
the general topographical setting results in locally humid
conditions. The underlying rocks are acidic Cambrian grits of the
Harlech Dome complex, but there are numerous intrusions of base-rich
rocks in the area, resulting in a rich and diverse flora and
vegetation. A second wood, occupying a small valley and east-facing
slope to the west of the Afon Artro, is mostly on more base-rich
soil than the main part to the east.
The dominant tree is oak,
Quercus petraea, with some birch, rowan
and holly (rather rare). In wet areas along streams and in flush
bogs, alder is locally dominant, with willows Salix aurita and S.
cinerea. The shrub layer is poorly developed with scattered hazel
and some hawthorn. The ground flora on moist but well-drained sites
is predominantly grassy with Deschampsia flexuosa, Agrostis spp.,
Molinia caerulea, and an abundance of Potentilla erecta, Galium
saxatile, Pteridium aquilinum, and Melampyrum pratense. Ash and
hazel are abundant in the wood west of the river, and a basiphilous
field layer is well developed here.
Throughout the wood there
are rock outcrops, some of which are
virtually ungrazed, supporting an abundance of Luzula sylvatica and
Vaccinium myrtillus, with Rubus fruticosus agg., Corydalis
claviculata, and in shaded areas Hymenophyllum wilsonii and, more
rarely, H. tunbrigense. These outcrops and boulders in the wood
provide habitats for rare or local Atlantic bryophytes, such as
Dicranum scottianum, Lepidozia pinnata, Adelanthus decipiens, Har-
panthus scutatus, Plagiochila punctata, P. tridenticulata,
Jamesoniella autumnalis, and Bazzania trilobata. The luxuriance of
the bryophyte growth in the wood is one of its most important
features, for besides the common woodland species, it supports
several local species in abundance, for example Hylocomium umbratum,
Leucobryum juniperoideum (only a few other localities in Britain)
and Lepidozia pearsonii.
There is a good epiphytic
lichen growth on the trees and rocks with
Lobaria pulmonaria, Sticta sylvatica, S. limbata, S. fuliginosa and
Sphaerophorus melanocarpus. The western sector with abundant ash is
especially rich in lichens. Rotten logs provide specialised habitats
for several interesting liverworts, such as Tritomaria exsecta,
Scapania umbrosa and Blepharostoma trichophyllum.
In waterlogged areas within
the wood, as on terrace flats, there is
a range of interesting flush bogs with Juncus acuti-florus,
Hypericum elodes, and Scutellaria minor, and a range of bryophytes
including Sphagnum imbricatum, S. contortum, and S. warnstorfianum.
Small rivulets flowing through the wood provide habitats for several
rare hepatics, such as 80 Woodlands
Porella pinnata, Aphanolejeunea
microscopica, Cephaloziella
pearsonii, and Jubula hutchinsiae.
The principal interest
of this wood is the rich and varied Atlantic
bryophyte and lichen flora, and the intricate woodland mosaic
related to topographical features. It provides one of the finest
examples of the range of woodland bryophyte habitats in western
oakwood, and in north Wales is second only to Coed Ganllwyd in this
respect.
W.IIO. BRYN
MAELGWYN & GLODDAETH,
CAERNARVONSHIRE SH 8o8l.
80 ha
Grade 2
This is one of a group
of similar woodlands on Carboniferous
Limestone close to Llandudno. It is high forest of ash, wych elm and
oak, with some sycamore and yew, and a shrub layer with privet,
hazel and hawthorn, over a calcicolous ground flora with
Brachypodium sylvaticum and Mercurialis perennis dominant. The
woodland grades through scrub of hawthorn, clematis, privet,
blackthorn and bramble to limestone grassland containing the rare
Veronica spicata ssp. hybrida.
Other woods in the group
are Pydew Pabo, Caernarvonshire, and Bryn
Euryn, Denbighshire. Whilst Pydew Pabo is regarded as marginally the
best woodland in the group, Bryn Maelgwyn is chosen because it is
adjacent to and grades into rich limestone grassland.
W.III. HAFOD GAREGOG, CAERNARVONSHIRE
SH 6044.
115 ha
Grade 2
This cluster of woods is
situated on a number of low, rocky hills
and ridges rising abruptly from the estuarine flats (now reclaimed)
associated with the Afon Glaslyn. About half the area is woodland
and the other half mire or lake. The tree layer consists of mainly
sessile oak in mixture with birch, rowan and holly, and with a
sparse shrub layer of hazel. The field layer is generally
acidophilous in character, being dominated by Anthoxanthum odoratum,
Festuca ovina, Melampyrum pratense, Potentilla erecta and Oxalis
acetosella, with Pteridium aquilinum in more open areas. There are
historical reasons for supposing this to be an area in which there
has been a long period of continuous woodland cover. In floristics
the wood is fairly typical of western sessile oakwood, but the site
is unusual in being on flat or gently sloping ground, in contrast to
many of the remaining hill woodlands in Wales, most of which occur
on steep slopes as oak hangers.
W.II2. COED
MAES YR HELMAU: TORRENT WALK, MERIONETH
SH 7518.
25 ha
Grade 2
This deep rocky glen near
Dolgellau has fringing woodlands with both
sessile oak on acidic soils and mixed deciduous wood on basic soils.
Some of the oaks in particular are tall, well-grown trees, and this
site is regarded as of national importance mainly for the quality of
these two contrasting types of woodland and their respective field
layers. The wood is ungrazed, and the ash-wych elm-hazel woodland
has fine examples of herb-dominated field communities
with Mercurialis perennis,
Filipendula ulmaria, Asperula odorata and
Brachypodium sylvaticum. There are a few non-indigenous trees, but
small-leaved lime in the glen may well be native. The gorge carries
a large stream but is less deep and spectacular than the Coedydd
Dyffryn Maentwrog gorges (W. 107). There are block strewn areas of
the woodland floor, with some moisture- and shade-loving ferns and
bryophytes (e.g. Hymenophyllum wilsonii, Scapania gracilis,
Plagiochila spinulosa and Bazzania trilobata) and many trees are
thickly clothed with moss. On the whole though, the Atlantic element
of the flora is not outstanding, and the more notable species (e.g.
Hymenophyllum tunbrigense, Iso-thecium holtii, Radula valuta and
Jubula hutchinsiae) are confined to the gorge itself.
The contrast between the
Coed Macs yr Helmau and Atlantic bryophyte-
rich woods such as Coed Ganllwyd appears to result not from
difference in present conditions -since none is obvious - but from a
different history of management. The Coed Macs yr Helmau woods
appear to have been replanted after a period of clearance during
which moisture-loving ferns and bryophytes disappeared, except from
the actual ravine. When the wood grew up again, only the more common
species were able to spread back to recolonise the suitable habitats
which developed. By contrast, at Coed Ganllwyd, it would appear that
there has been continuity of woody cover - if only of scrub - over
at least part of the site throughout the Post-glacial Period, so
that drought-sensitive species survived somewhere and spread again
when high forest was restored after nineteenth-century clearance and
replanting of oak and beech.
W.II3. COED
LLETY WALTER, MERIONETH
SH 6027.
45 ha
Grade 2
This woodland lies at 60-80
m on fairly level ground, north of the
Afon Artro, and at the mouth of the valley, about 5 km from the sea.
The bed rock is Cambrian grit and the rainfall about 200 cm
annually. The wood is young, 30-40 years old perhaps, with a
dominance of naturally regenerated oak and birch. Other species
present include ash, alder, rowan and holly. A few large Scots pine
and beech remain as remnants of the previous woodland. The ground
flora is predominantly acidophilous but there are local occurrences
of Brachypodium sylvaticum and Geranium robertianum indicating some
base enrichment. The wood is notable for a wide range of habitats in
the form of rock outcrops, short slopes with various aspects,
streams, wet flats and glades.
W.II4- COED
LLECHWEDD, MERIONETH
SH 5932.
55 ha
Grade 2
The wood occupies a steep
north-west-facing slope just north of
Harlech, looking out over Morfa Harlech. Altitude ranges from 15-180
m and the exposure to wind is moderate to severe. The underlying
rocks are Cambrian and the diverse woodland vegetation suggests the
presence of base-rich rock outcrops. The tree layer is dominated by
oak but a wide range of other trees are present, including less
common species for this area, such as gean. There are both
acidophilous and basiphilous elements
in the ground flora, as
indicated by the presence of heather and Allium ursinum. This is a
good example of a hill wood with considerable ecological diversity
resulting from varying base content of the soil. |
|
|
|
|
|
