Micro-woods

Pepperknowes Farm east felled wood, visit 5 Sep 2011

2011-10-03T06:36:00.000-07:00

Despite the lower slopes being carpeted with Foxglove in previous years there are areas emerging which have other dominant species. These locally dominant species are, besides Foxglove, Yorkshire Fog, Bracken, Nettle. Tufted Hair Grass and Common Bent are abundant in the Yorkshire Fog - dominated areas. Common Bent dominates the tops of the rocky outcrops. Chickweed is very abundant in the Foxglove-dominated areas. It dominates the sub-layer beneath the Foxgloves, filling in the gaps between the Foxglove leaf rosettes. Sycamore regrowths flourish and form a significant scrubland in some parts of the wood. See photos in the linked Picasa album.

It is probably most useful to monitor species frequencies as well as looking out for incoming species such as those arising from the seedbank.

Glencarse Hill update, 26 July 2011

2011-07-27T07:31:00.000-07:00

The most interesting micro environment is the gravel pit which has thin, very poor soil, rather than the hill itself. Presumably the gravel is a glacial, carse deposit. The flora will inevitably be more dynamic here than elsewhere as pioneer species come in and are themselves superceded in the struggle for scarce water and nutrients. For this reason two permanent quadrats have been established to observe this species flow.

The updated species list is in the associated Picasa album along with a few additional photos. Two of the photos are of a phylloid infloresence of Trifolium repens (White Clover) found on a roadside verge. The petals (standard, wings and keel) could be made out in the ‘florets’. The anthers and female parts needed more imagination.

Glencarse quarry update visits 20 Jun and 13 Jul 2011

2011-07-21T08:22:00.000-07:00

These were short visits mainly to catch the blooming of Northern Marsh Orchids (Dactylorchis purpurella). These produced a fine show in 2009 but in 2010 they were badly grazed by deer. The photograph accompanying this posting shows that we did catch them in June 2011 when we counted about 140. They were not fully open on this date so we made a further visit in July 2011 but found them deer-grazed. In fact we disturbed one of the culprits, a young red deer stag, as we entered the quarry.

Some minor additions were made to the species list and the amended version is in the associated Picasa album (click the orchid picture to see).

Updates to Pitroddie Den botany blog, July 2011.

2011-07-20T08:08:00.000-07:00

Trackways were found to have been cleared , and much shrubbery, notably Buddleia, had been cut back making the den easier to access. Photographs obtained during update visits have been added to the Picasa album , Pitroddie Den, numbers 58 to 79. Species list has been updated (photo titles prefixed Spp). Scales shown in the photos of mosses and liverworts are cm/mm.

Visit to Pitroddie Den, 5 April 2011

1. In flower (ie coloured bud or later flowering stage)

Vernacular name	Genus	species
Anemone	Anemone	nemorosa
Coltsfoot	Tussilago	farfara
Daffodil	Narcissus	pseudonarcissus
Dandelion	Taraxacum	Sect. Ruderalia
Dog Violet	Viola	riviniana
Dogs Mercury	Mercurialis	perennis
Goat Willow	Salix	caprea
Golden Saxifrage	Chrysosplenium	oppositifolium
Gorse	Ulex	europaeus
Lesser Celandine	Ranunculus	ficaria
Marsh Marigold	Caltha	palustris
Primrose	Primula	vulgaris
Sloe	Prunus	spinosa

2. Permanent quadrat established: serial number 1, circular, 0.5m diameter, Grid ref 20404 25236, 7.6m bearing 090 degrees magnetic from electricity pylon no.45 ; photograph orientation = 12 o’clock position bears 360M from quadrat centre.

The moss within the quadrat is Hylocomium splendens. The other plants are Wild Strawberry (Fragaria vesca), Primrose (Primula vulgaris) and Cocksfoot (Dactylis glomerata).

Corrections to some identifications

2011-04-19T06:38:00.000-07:00

The postings relating to Craighead Quarry show Red Catchfly (Viscaria vulgaris) as being in the area. This is actually Common Centaury (Centaurium erythraea) .

The postings relating to Glencarse Hill show Great Water Dock (Rumex hydrolapathum). This is an outsized specimen of Curled Dock (Rumex crispus).

The postings relating to Glencarse Quarry show Greater Burnet Saxifrage (Pimpinella major). This is Common Valerian (Valeriana officinalis).

These corrections are by local expert Martin Robinson, at present writing a Rare Plants Register for East Perthshire, to whom many thanks.

Kingoodie Quarry update

2010-08-26T12:32:00.000-07:00

The species list has been amended as of 26 August 2010 and the latest version can be seen in the linked Picasa album. Most notable sighting today was of Common Twaylade - past flowering but still obvious. Amazing we did not see it last year.

Glencarse Hill update, 26 July 2010

2010-08-05T08:26:00.000-07:00

There is a field just below the main hill which is source of sand and gravel for the local council. It has ecology fundamentally different from the wooded steep slab of basalt which makes up the main part of Glencarse Hill. The first four photos show plants in this environment, namely white and yellow Verbascums (photo1), Weld (photo 2), Scarlet Pimpernel (photo 3) and Musk Mallow (photo 4). All these were growing in an austere environment of little or no soil and extreme dryness. Photo 5 shows the view south towards the Fife hills from the foot of the hill.

Photo 6 shows a wooded area of the hill dominated by Male Fern. Other locally dominant herb layer species are Dog' Mercury and Nettles. Another fern found on a rock face was Black Spleenwort (photo 7.) Ringlet butterflies (photo 8) were common. Nipplewort (photo 9 was found in the wood. There were spectacular docks in flower. See photo 10 for the full size of this collapsed six-foot specimen of what can only be Great Water Dock though there was no water in its vicinity. Photo 11 is a close up of the inflorescence.

Photo 12 is not a picture of a lemon meringue pie but of Bolete Mould. Photo 13 shows an infected specimen of a Boletus sp. Nearby.

Of particular interest from this exped.:

1. Scarlet Pimpernel turns up again – this is supposed to be a rare plant

2. The mass of Verbascums on sand deposits

3. Musk Mallow – also being found quite widely on other sites

4. The magnificent specimen of Great Water Dock.

Craighead Quarry, update 13 July 2010

2010-08-01T08:27:00.000-07:00

(PLEASE REFER TO THE PHOTOS IN THE ASSOCIATED PICASA ALBUM - THE LINK IS ON THE RIGHT OF THIS PAGE.)

Photo 1 shows the view south across the Carse of Gowrie towards the River Tay seen in the distance. Wood False Brome Grass, in flower, was very abundant. This is a late-flowering grass. Scarlet Pimpernel (photo 2) was widespread in many areas of short grass, more so than at last year's visit.. Usually it grew on the path verges. Another big change from the last visit was the widespread occurrence of Red Catchfly (photos 3 and 4). It mainly grew on sandy banks along the path to the summit. Common Fiddleneck (photo 5) was found at the edge of the path. Agrimony was found in the meadow-like area between the path and the wood. It grew in similar areas to Musk Mallow (photo 6), also seen for the first time this year.

The species list has been updated using the data from the 13 July 2010 visit.

Notable finds from this exped.

1. Red Catchfly (two stars in McClintock and Fitter) - there was quite a lot of this. I can't think why we didn't see it before, but then Scarlet Pimpernel had increased markedly from last year when only one plant was seen.

2. Musk Mallow – this seems to be spreading in the Carse (see the posts on Glencarse Quarry)

3. Scarlet Pimpernel was almost abundant

4. Fiddleneck – an unusual find but could indicate further invasion by alien species

Glencarse Quarry update 13 July 2010

2010-07-27T13:53:00.000-07:00

(PLEASE USE THE LINK ON THIS PAGE TO THE PICASA PHOTO ALBUM FOR GLENCARSE QUARRY UPDATE JULY 2010)

Photo 1 shows the entrance to the wood. Meadowsweet is common here but amongst it was Monkshood (photo 2) presumably a garden throw-out. Gooseberry was found amongst the shrubs lining the road and Lesser Stitchwort in the rough turf by the entrance to the wood. Further in Himalayan Balsam has taken hold but it did not look as vigorous as last year. Nettles are in abundance too. Beneath the quarry face the land is very marshy. There are lots of Northern Marsh Orchid here but most have been eaten back by deer. Wood False Brome grass is abundant. Male fern is very abundant and Lady Fern was also found.

Down on the lower scree level the land is still marshy in parts. In the marshy area there is an abundance of rushes such as Soft Rush (photo 3), Wood Clubrush which formed an impressive thicket (see photos 4 and 5) and reed-like grasses (Reed and Reed Canary Grass (photo 6). Commonly found were Hairy Sedge (photo 9) and Common Sedge (photo 10). Also here Greater Burnet Saxifrage, pink and white versions (photos 9, 10 and 11), and Common Horsetail grew in abundance. There is a drier area with a mound of earth on it supporting Brambles and a good display of Musk Mallow (photo 12). The mallow was seen last year but the Aquilegia seen then had not appeared this year. Marsh Thistle (photo 13) was frequent. The rough turf was made up of Sweet Vernal Grass, other unidentified grasses, Tormentil (photo 14), Bird’s Foot Trefoil, St John’s Wort, Wild Strawberry, Common Catsear and Self Heal. Leopardsbane and Butterbur dominate large areas but both had finished flowering at the time of this update.

Interesting features of today’s exped.

1. Finding Monkshood and Musk Mallow - very showy.

2. Club Woodrush – this is a really in-your-face plant and has two stars in McLintock and Fitter.

3. Finding a Gooseberry bush full of gooseberries which I will harvest this week.

4. Bit annoyed to find the orchids were deer-damaged. Will check back later to see if they have recovered.

5. Disappointed to see the Aquilegia has not re-appeared. The Meadow Saxifrage was not seen either. Possibly choked out by Himalayan Balsam.

Reference:

McClintock, D. & Fitter, R.S.R., 1967. Pocket guide to wild flowers, Collins, London.

Grass identificaton

2010-07-05T12:02:00.000-07:00

Grasses can be difficult to identify because they look similar at first glance. You can use a binary key but I can never get them to work. I think that's because the key criteria can refer to different stages and habits of growth. You might be studying one criterion which refers to the flower and at a later step be referred to the basal leaf characteristics or the means of perennation - and you forgot to collect a leaf from the bottom of two foot-deep grassland or take a spade to check on whether your grass was stoloniferous or rhizomatous.

Some grasses are easy and don't need a key. Cocksfoot is very distinctive, as is Ryegrass. Yorkshire Fog is only slightly less so. Brome-like grasses such as true bromes and false bromes are distinctive and you would be quicker studying the few pages describing these two groups in your reference text (e.g. Hubbard, 1968 and later) than flogging through a key.

The difficult ones are the small grasses which grow together and have pyramidal infloresences formed by clusters of raceme branches with wider branches at the base and shorter ones at the top. When the infloresences fully open out you get a 'fog' of spikelets. The main groups of small 'pyramidal fog' grasses are Meadowgrasses, Bents, Fescues and Wavy Hair Grass (Deschampsia flexuosa).

Key characteristics for distinguishing between small 'pyramidal fog' grasses.

In the first paragraph under each group below I describe how you can identify the group (genus) and in the other paragraphs how you can differentiate between the commonest types.

Meadowgrasses (Poa)

These have 2 to 5 flowers per spikelet (so the spikelets are pretty small but not tiny as are those of the Bents which have one flower per spikelet)

They do not have awns.

They often have boat-shaped tips to the leaf blades (but not always and the tips often get damaged anyway - so not reliable).

The two Poas which are most difficult to differentiate are Smooth Meadowgrass (P. pratensis), often described as 'more or less smooth'; in other words it could be rough! and Rough Meadowgrass (P. trivialis), often described as ' more or less rough; in other words it could be smooth! Forget the smoothness and roughness, look at the ligule. If it's difficult to see that it has a ligule at all it is P. pratensis. If the ligule is long it is P. trivialis. The ligule (the membranous structure which clasps the culm at the top of the leaf sheath and indicates where the leaf blade starts) is very resilient. Even if the leaf has died you can still usually see the ligule by gently pulling the blade away from the culm.

Bents (Agrostis)

These are the only common grasses which have one flower per spikelet.

To differentiate between Bents use the following guide:

Common Bent (A. tenuis) has no awns and a short ligule.

Brown Bent (A. canina) has awns and a long ligule.

Creeping Bent (A. stolonifera) has no awns and a long ligule.

Black Bent (A. gigantea) also has no awns and a long ligule but is big (up to 120cm tall) and much less common than A. stolonifera.

Fescues (Festuca)

These have quite large, usually flattened spikelets which have at least three and up to fourteen flowers. Because they have relatively large spikelets they are less 'foggy' and more chunky than the other groups described.

Sheep's Fescue (F. ovina) and Red Fescue (F. rubra) are not easy to distinguish between. Both have awns and very short ligules. F.rubra is larger than ovina. The leaf sheath is entire in rubra but split in ovina. F.ovina grows on moorland whereas rubra grows anywhere.

Meadow Fescue (F. pratensis) is larger than rubra and ovina and awnless.

Wavy Hairgrass (Deschampsia flexuosa)

This has awns and two flowers per spikelet.

The other common Deschampsia is D. caespitosa (Tufted Hair Grass) but it is a very large plant and not easily confused with D. flexuosa.

Reference

Hubbard, C.E., 1968. Grasses. Penguin, Middlesex.

Pepperknowes east felled wood update 21 June 2010

2010-06-26T12:58:00.000-07:00

The site can be seen as a purple hill (photos 1, 2, 3) as predicted from the carpet of Foxglove seedlings seen last year. There are rare white plants (photo 4), indicating a recessive character. Beside the foxgloves there are several locally abundant/dominant species, namely Bracken (photo 5), Dog's Mercury, Nettles and Sycamore regrowths. It is pleasing to see Scarlet Pimpernel continuing to thrive on the margins of the fields adjacent to the felled wood. So apart from the Foxgloves there are no obvious species establishing from the seed bank on this site. Next year may be more interesting as competitors to the Foxgloves may arise. There may be some evidence of this towards the tail-end of this growing season. At least we have established a baseline against which new species can be identified.

The update to the species list is in the linked Picasa album.

Update on Pitroddie Den blog

2009-12-08T06:38:00.000-08:00

Pitroddie Den is on Old Red Sandstone and basalt. The sandstone is in the Devonian Arbubuthnot-Garvock Group.

Reference: British Geological Survey One Geology web-site (http://portal.onegeology.org/)

Mosses

2009-12-08T06:32:00.000-08:00

The trouble with mosses is that they all look like – moss. Macroscopically they are difficult to differentiate and a reasonably powerful microscope is required to examine leaf structure, including down to cell level. A good reference book is needed. Roger Phillips’ (1980) photographic reference is limited because it only shows macroscopic structures. His pictures of fruiting bodies are useful but are necessarily limited to fruiting plants. The reference I have used most is Watson (1959), using Phillips to check the nomenclature.

Glencarse Hill:

The following were found on a sandy bank:

Dicranella heteromalla

Atrichum undulatum (Catherine’s Moss)

Glencarse wall dwellers:

Bryum capillare

Grimmia pulvinata

Hypnum cupressiforme

Brachythecium rutabulum

Glencarse road edge:

Brachythecium albicans

Kingoodie Quarry:

Plagiomnium undulatum

Fissidens taxifolius

Hypnum cupressiforme

Acrocladium cuspidatum (this is fairly easy to identify with the naked eye as it is the only moss with spear-head-shaped (cuspid) shoot tips.

References:

Phillips, R., 1980. Grasses, ferns, mosses and lichens of Great Britain and Ireland. Pan Books, London.

Watson, E.V.,1959. British mosses and liverworts. Cambridge University Press, London.

Glencarse Hill

2009-10-31T10:35:00.000-07:00

10 km south-west of Abernyte, 6 km west of Errol

Basalt hill. Tree layer = mix of Ash, Oak, Elm, Beech and Sycamore. Shrub layer generally not well defined.

(Please refer to the photo album on Picasa)

Glencarse Hill is a basalt outcrop with much of the surface covered in an active scree of basalt chips (photos 1-3). The soil found was clayey and contained basalt boulders (photo 12), - probably a glacial deposit. It is possible that, on the steep slopes, the basalt chip scree has covered the glacial deposit as the chips appeared fresh, unmixed with clay and poor in herb species. However this was not possible to verify due to the scree being mobile. Exposure of the rock is frequent (photo 11). A mixture of forest tree species grow on the steep slopes (photo 4) with sycamore (photo 8) being the most abundant. Pedunculate oak is common (photos 6-7). There are a few conifers, Spruce growing at the foot of the hill and Scots Pine on the steep slope. Wild Cherry is frequent (photo 5). A couple of specimens of Cherry Laurel were found (photo 10). Wild Cherry is frequent (photo 5). Elder, Bramble and young Elm pre-dominated in the shrub layer. In the herb layer Bracken (photo 13), Dog's Mercury (photo 14), Wood False Brome Grass (photo 15) and Nettles were locally dominant. Lichens found on dead wood were Xanthorium parietina (photo 16) and Pseudevernia furfuracea (photo 17).

Pepperknowes eastern felled wood update

2009-09-18T13:16:00.000-07:00

By the middle of September 2009 the site could be seen from a distance to have greened up considerably with many large clumps of foliage arising from the background vegetation. The last posting on this wood stated that Foxglove carpeted the area. On the most recent visit (16 Sep 09) this carpet was changing to a mass of rosettes each about 25cm in diameter photo 3), representing individual plants which had successfully competed from within the population. The large green clumps seen from a distance proved to be re-grown Sycamore (photos 1 and 2). These were about 1.2 m high. Small young Sycamore weed trees had been felled when the Larch and Spruce were harvested. If allowed to develop these re-grown shrubs will dominate the scrubland and could be a problem for re-planting operations due in the next few years. Elder (Sambucus nigra) was also found re-growing from stumps but not as vigorously as the Sycamore.

Changes to the frequency codes for species are given below. Please see the Pepperknowes east felled wood plant species list for the original frequencies.

Sycamore (Acer pseudoplatanus) frequency = f.

The following were identified growing out of a basalt outcrop:

Corylus avellana (Hazel), frequency = r

Saromanthus scoparius (Broom), frequency = r.

Pteridium aquilinum (Bracken), frequency = f

On top of the basalt outcrop was rabbit-grazed turf dominated in equal amounts by Agrostis tenuis (Common Bent) and Festuca ovina (Sheep’s Fescue) – overall frequencies throughout the site = f in each case. Holcus lanatus (Yorkshire Fog) and Foxglove were also found here.

Bracken throughout the site was re-growing quickly and the frequency rating for the whole area = a (frequency = f for the basalt outcrop).

Felled remains of Betula verrucosa (Birch) were seen but there was no evidence of re-growth. Frequency = o.

Chickweed (Stellaria media) was abundant throughout the area (frequency =a).

Poa annua (Annual Meadow-grass) was seen on bare soil (frequency = o) and also Chamaenerion angustifolium (Rosebay Willowherb; frequency = o).

Himalayan Balsam (Impatiens glandulifera) was also invading (frequency = f).

Prickly Sow thistle (Sonchus asper) and Spear Thistle (Cirsium vulgare) were seen (frequencies both = r).

Pepperknowes, eastern felled wood

2009-09-04T08:07:00.000-07:00

5.5 km east of Perth, 12 km south-west of Abernyte.

Grid references of points on the boundary:

1. 18795 22076

2. 18744 22061

3. 18694 21963

4. 18701 21837

5. 18722 21832

6. 18730 21835

7. 18737 21870

8. 18842 21945

9. 18797 22076

(Please view the photo album in Picasa when reading the notes below. The photo album also contains the plant species list. Please click the link in the right-hand column.)

This wood is situated in Pepperknowes Farm, Glencarse, Perthshire. It is one of two Spruce/Larch woods on the farm which were felled for commercial purposes in 2008. The hope is that the seed bank on the site will manifest itself as the habitat changes from woodland to scrub/heath/meadow. These notes are therefore base-line observations taken when the area was cleared of timber. Brushwood has been left lying over the whole site. There has been aggressive pioneering of the site by Nettle, Dog’s Mercury, Yorkshire Fog, Bracken and Foxglove. Some Foxgloves flowered this year but most notably the area is carpeted with Foxglove seedlings which will not flower in 2009. Non-flowering Elder seedlings are also abundant.

There is a rocky outcrop in the middle of the site. This had a Dandelion-like flower (recorded as a Hawksbeard) growing out of it. Yorkshire Fog was by far the most abundant grass throughout except on the heath type area on top of the outcrop where Sweet Vernal appeared to dominate, although possibly not all grasses here were identified at the time of writing.

Scarlet Pimpernel was found at the edge of the former wood, where it meets a cultivated field.

An Orange Tip butterfly (Anthocaris cardamines) was seen in the vicinity.

Kingoodie Quarry

2009-08-26T13:26:00.000-07:00

Grid references: Pond 1 = 33955, Pond 2 = 33896 29505 and Pond 3 = 33787 29444.

(Please view the photo album in Picasa when reading the notes below. The photo album also contains the plant species list. Please click the link in the right-hand column.)

This is a sandstone quarry containing three large ponds. The wood has a complex tree layer comprising mainly Ash, Sycamore, Elm (photo1) and in the vicinity of the ponds, Grey Willow (photo 2). Less abundant are Beech and Oak. The shrub layer comprises Hawthorn and Goat Sallow. The herb layer within the wood is dominated by Ivy or Nettles. There are breaks in the wood where meadow conditions are found (photos 5 and 6). Here the dominant species are grasses – not all identified at the time of writing but including Bent, Cocksfoot, Yorkshire Fog and Wavy-hair Grass. Very abundant in these meadow areas are Rosebay Willowherb, Ragwort and St John’ Wort. Also Ox-eye Daisy and Black Knapweed (photo 7).

Ponds 1 and 2 had large areas of Reed (photo 8). Duckweed was very abundant in Pond 3 (photo 4). There is a shale scree at Pond 2 which is being colonised by Birch and Yarrow (photos 3 and 9). Pond 1 had an abundance of Water Forget-me-not (photo 10).

The shrub layer within the woodland habitat contains an abundance of Ash and Sycamore seedlings. Bridging the tree and shrub layers are Crab Apple and Honeysuckle.

Notable herb species of some rarity within the woodland habitat are Stinking Hellebore, Goldilocks (photo 11) and Wall Lettuce (12) all in the vicinity of Pond 1.

The plant species list is in photos 13 to 16.

Craighead Quarry

2009-08-17T13:29:00.000-07:00

Grid ref: 23822 27836, 5km from Abernyte, 5km from Inchture

(Please view the photo album in Picasa when reading the notes below. The photo album also contains the plant species list. Please click the link in the right-hand column.)

Craighead Quarry is a basalt quarry, much of the basalt is crumbly. The route investigated climbed over the top of the quarry. No exploration was carried out at the foot of the rock-face (see photos 1, 5 and 6).

The tree layer is a mix of Ash, Elm, Sycamore, Spruce, Yew, Birch, Oak, Rowan (photos 2 and 3). The woodland is difficult to categorise having been invaded by Sycamore and planted with Spruce but is probably naturally Ash-wood perhaps progressing to Oak-wood. The Birch trees are large and mature specimens (photo 2) and could may have been original natural pioneers, Birch being often the first trees to colonise bare ground. Rhododendron (photo 6) has started to invade the shrub layer and Bay-willow has been planted. The wild shrubs are Wild Cherry (photo 4), Hawthorn, Crab Apple, Sloe, Elder and Bramble.

The meadow habitat was restricted to the margins of the wood. The stony habitat was mainly the path. Plants of note were Scarlet Pimpernel (photo 8) and Pirri-pirri Bur (photo 9) both of which were growing at the edge of the path. Scarlet Pimpernel is regarded as a rare plant. Pirri-pirri bur is a New Zealand plant. It was well-establised at Craighead. Teasels were found in a lay-by at the edge of the wood (photo 7).

A Common Blue damsel fly (Enallagma cyathigerum) was seen in a meadow habitat.

Glencarse Quarry

2009-08-04T13:08:00.000-07:00

Grid reference of gate is NO 18207 22428

(Please view the photo album in Picasa when reading the notes below. The photo album also contains the plant species list. Please click the link in the right-hand column.)

This is a small, wooded basalt quarry near Pepperknowes farm on the Balthayock road from Glencarse village (see photos 1 and 2 showing the wood from the east and west respectively). There is a quarry face with two levels of scree. Photos 3 and 4 show the upper scree directly below the rockface and photo 5 shows the lower scree. There is a marshy area below each scree. The upper one has the remnants of quarry buildings and machinery.

The wood is best described as a mixture of Ash, Elm and Sycamore in the tree layer with Rowan and Hawthorn in the shrub layer. If Sycamore is regarded as a recent invader the composition fits the Ash/Hawthorn model which is typical of natural woods on basalt.

Particularly striking in this wood are the phases of local dominance/abundance in the field layer by Butterbur (smothering a large area of the lower level down to the road in April; photo 6) followed by Leopard’s Bane (dominating the lower scree in June; photo 7) and Northern Marsh Orchid abundant on the upper scree level in July (photos 11 and 12).

Other plants showing local dominance in the field layer are Dog’s Mercury and Nettle.

Two surprising finds were Aquilegia (photo 9) and Musk Mallow (photos 14 and 15) growing on the same patch of ground on the lower level (not in flower at the same time). Both occur wild but could be garden escapes. Leopard’s Bane (photo 7) is also a garden flower but it is found wild and in abundance in the local area, particularly along the side of the high road to Perth behind Binn Hill.

Solitary plants of Heath Spotted Orchid (photo 10) and Meadow Saxifrage (photo 16) were found.

The occurrence of Laburnum and Cotoneaster may indicate deliberate planting. Unfortunately Himalayan Balsam has invaded a small area under the tree canopy.

The plant species list indicates that marshy conditions are an important influence on the flora here as indicated by the presence of bog-tolerant rushes, sedges, Water Avens (photo 8) Ragged Robin, marsh orchids (photos 11 and 12) and Marsh Thistle.

(Please use zoom to see the butterflies in photos 18 to 21.)

Pitroddie Den wood

2009-07-31T08:33:00.000-07:00

Situated 5km from Glencarse and 8km from Abernyte, Perthshire, Scotland.

Grid ref. NO 200252

Please use the Picasa photo album (see link at top right) when reading this blog.

The plant species lists are also included in the Pitroddie Den photo album (see link box)

A den, or in England a dene, is defined as a deep, narrow wooded valley of a small river. In this case the small river is Pitroddie Burn.

This first picture in the album is taken from land above the Den in mid-May looking east. Pitroddie Den has a narrow, rocky central area which is flanked by steep slopes. Flagstone was quarried here. In fact there are two main rocks forming quarry faces – flagstone and (volcanic) basalt.

Ash and hawthorn are the dominant plant species in the Den’s tree and shrub layers respectively. These are not just any plants that have sprung up by chance in this area. They are a part of a known progression of plant colonisation.

There are two theories of British woodland development. One is that land below the tree-line was virtually all woodland until man came along and cleared areas by a combination of axe, fire and grazing animals. If the woods were allowed to develop influenced only by climate the land would finally end up as what is known as the climatic climax vegetation system. This is the vegetation system which will ultimately be reached for a given climate if an area is undisturbed by man. In our case that is a temperate, maritime climate.

In the British Isles there are two main climatic climax vegetation systems which exist on dry land below the tree-line. These are oak wood and beech wood. In other words if there was no farming (such as crop production and grazing) forestry operations or urban development, almost all the land in the British Isles would be dominated by these forests.

The largest forest trees in the Den are neither Oak nor Beech. Instead it is Ash as seen in photo 2. This according to one model is because the vegetation system has not yet progressed to its climatic climax, Eventually the woodland will become either oak or beech wood. It seems pretty clear that it is heading towards beech wood as we can find some specimens of Beech but not of Oak.

Another theory of woodland development is that areas of woodland were always mixed with open spaces of heath or grassland (savannah) (See Rackham 2006, for a discussion of the Vera thesis). Evidence for this is obtained from pollen analysis of ancient soils, whereby grassland areas occur which do not contain tree pollen or contain only enough of it to indicate pollen blown in from outside. In the savannah model trees were commonly confined to thin, rocky soils, being unable to compete with heath and grassland species on deeper soils. Certainly in Pitroddie Den the trees are mainly confined to the steep slopes and scree.

In the photos you can see the layering of the taller ash (not yet in leaf in May) and the shrub layer below it – Hawthorn.

Photo 4 is of the land along the burn to the west of the den. This area is much wider and flatter but is at the same altitude and watered by the same burn – but instead of ashwood it is turf. It is possible that the area we see here is not being allowed to progress toward its climatic climax vegetation system and the reason for that is it is grazed by sheep. Or the tree and shrub layers can not compete with the herb layers on the deeper soil.

The shrub layer in Ash woodlands is commonly dominated by either Hawthorn or Hazel. In our case it is Hawthorn.

We also see the common occurrence of Sloe (Blackthorn) in the shrub layer. (Bracken is shown in the herb layer in photo 6). So while Ash and Hawthorn are dominant in the tree and shrub layers other species may be frequent, occasional or rare. Other common shrubs or small trees are Wild Cherry and Goat Sallow. Photo 8 shows Hawthorn blooming in June with Sloe going out of flower. Honeysuckle, Elder and Dog rose are also coming into flower at this time. Gorse should be mentioned. It grows in the grazing areas above the woodland and can grow where the woodland species can not because it is resistant to extremely dry, windy conditions. It survives the sheep because they won’t eat its spiny foliage.

Photo 9 shows the gate at the eastern entrance to the Den at the beginning of April, (2008). Photo 9 shows the same gate a fortnight later and photo 10 in May. It shows the shrub layer in leaf and the herb layer is here dominated by Nettles. Photo 12 shows the gate in mid-July totally overwhelmed.

Photo 13 shows the (railway sleeper) bridge over the burn in May and photo 14 shows it in July (from the opposite direction).

There is a huge clump of Buddleia (photo 16), locally dominant over Hawthorn in the shrub layer. In mid-July the Buddleia clump is almost impenetrable. Here Nettle is dominant in the herb layer – in light shade.

Photo 17 shows Dog’s Mercury as the dominant herb layer species in deeper shade and moist conditions

Photo 18 shows the trees and shrubs clearly marking out a tributary of Pitroddie Burn from a spring on the north slope.

Photo 19 shows the face of a sandstone quarry on the north slope. Ash, Elm and Hawthorn are at its foot. Photos 20 ad 21 show a basalt outcrop. Plants growing out of the bare rock, are Sycamore, Dog Rose, Gorse, Stonecrop, Hawkweed and Sea Beet and again a few weeks later with Dog Rose and Elder in bloom.

Outside the canopy Nettle is the dominant species (photo 23). Under the woodland canopy Dog’s Mercury or Nettle are dominant but other herbs can be locally dominant such as Bluebell (Wild Hyacinth; photo 24). Photo 25 shows blue and white variants together.

Other species are frequent in the herb layer of the woods such as Bugle, as seen in photo 26,Wood Anemone, Water Avens, Figwort and Herb Bennett.

Away from the woodland rabbit grazing has reduced the herb layer to turf with taller meadow species at the fringes of the wood. Photos 27 and 28 show turf in May. The brown vegetation is Sphagnum moss dried out. The turf here is a mixture of Sphagnum, Sweet Vernal Grass, Ash seedlings and the shoots of many broad-leaved plants.

Gorse in full bloom is shown in photo 28 and photo 29 shows the same area in July with the Gorse finished flowering and the turf starting to green up as the new shoots of broadleaved plants grow away.

Throughout the Den the turf is a mosaic of low-growing plants (see photos 30 to 41 and 48).

In early spring Primroses are abundant in the turf (photo 41) and frequent under the woodland canopy. In April the Early Purple Orchid blooms and later the Northern Marsh Orchid (photos 37 and 46).

At the boundary of and woodland, the meadow habitat, Primroses appear again, with Cowslip (photo 38) and the orchids but also here are taller-growing species. Water Avens (photo 42) is very abundant Meadowsweet in places co-dominant with Nettles (see photo 15), St John’s Wort (photo 39), Red Campion (photos 43 and 44) are seen here).

Surprisingly Marjoram is abundant in the meadow habitat (photo 49) although it appears as ‘locally abundant’ in a list of species growing on basic soils in ashwood cited by Tansley (1965), such as those on basalt rock. At Pitroddie Den Wood Sage and Basil are also frequent and Angelica is occasional.

Photos 50 and 51 are 2009 photographs showing Hawthorn in bloom from outside and inside the Den.

Butterflies seen are Dark Green Fritillary (photo 55), Meadow Brown (photo 56), Small Heath, Common Blue, Ringlet, Green-veined White (zoom in on the photographs to see).

References:

Tansley, A.G., 1965. The British Islands and their vegetation. Cambridge University Press, Cambridge ( 2 volumes).

Rackham, O., 2006. Woodlands. Collins, London