Ramsons carpets

Two recent woodland trips provided the inspiration for this post on ramsons (Alium ursinum). The first trip was an afternoon recce for some uncommon woodland flora when a visually compelling ramsons carpet was chanced upon in less than ideal lighting. Another location identified and added to the seemingly ever lengthening 'to visit under more idealised lighting' list.

To increase the chances of finding ramsons carpets an appreciation of their ecology is useful and a Hungarian research paper provides some useful insight into the habitat requirements amongst other things:

"In spite of its broad distribution across continents, and its occurrence as a weed, the species cannot be considered as a generalist. Several authors have classified it as a habitat specialist, having a rather narrow range of ecological tolerance (Grime et al. 1988, Kevey 1977, Rychnovská and Bednář 1998). A. ursinum is particularly sensitive to the availability of water. It requires a mesic soil, which is well-drained. Both drought and waterlogging are unfavourable (Csiky et al. 1999, Grime et al. 1988, Kevey 1977, Rychnovská and Bednář 1998, Trémolières et al. 2009, Tutin 1957). Sufficient humidity in the air is also crucial for survival (Kevey 1977, Kovács 2007)."

"The species strongly prefers the forest floor; it can rarely be found outside of a forest (Grime et al. 1988), only in some places with high, evenly distributed precipitation (Tutin 1957) or along rivers or streams (Kevey 1977)." 

"The plant requires a nutrient-rich soil (Tutin 1957)"

"A. ursinum is sensitive to the pH, missing from base-poor sands and mor soils (Tutin 1957). Falkengren-Grerup and Tyler (1993) demonstrated experimentally that mor (pH 3.6) inhibited the production of new roots. Tutin (1957) estimated the tolerated pH range from 5.5 to 7.9; Grime et al. (1988) narrowed it to 6–7.5" 

Extracts taken from Oborny, B., Botta-Dukat, Z., Rudolf, K. and Morschhauser, T., 2011. Population ecology of Allium ursinum, a space-monopolizing clonal plant. Acta Botanica Hungarica, 53(3-4), pp.371-388.

Ransoms are an indicator species of ancient woodland and some online detective work cross referencing national ancient woodland inventories e.g. Wales and England, against a relevant geology map will identify candidate sites of ancient woodland overlying calcareous bedrock. It is then a case of recceing the candidate woods.

The second trip was one made specifically to photograph a riparian carpet of ramsons within the Lower Wye Valley AONB on a rare day with overcast skies, the weather in May, thus far, has been mostly clear blue skies and sunshine. The woodland is designated as ancient semi natural and has outsize coppice stools of alder, ash, wych elm and hazel with a ground flora community of ancient woodland indicator species.

A spring woodland trip

A forecast of heavy overnight rain with clearing skies, negligible wind and the chance of mist, was the inspiration to set the alarm clock for a dawn outing. A bluebell wood recced on an evening visit a few days before would be the destination.

Wild boar foraging

Entering the wood just before sunrise and it became apparent that a) there was no ground mist, nor indeed any other type of mist and b) a sounder of wild boar had descended en masse to forage in the bluebell carpet in the area of wood that I wanted to photograph. Sigh. There were no signs of leaves or flower stalks sans bulbs, the boar seemed interested in something else and the bluebells collateral damage. Taking stock of the situation and the overnight rain had enlivened the mosses, wetted the leaf litter and the wind was negligible, so Plan B would be a visit to a scowles woodland 10 minutes drive away and hopefully the flora would be in flower.

Ramsons carpet

On the drive to the scowles wood I passed by patches of ground mist on fields and on the walk in there was a ground mist in the meadow adjacent to the wood. No mist in the wood though and reinforcing my view that woods have their own microclimate. Nevertheless there was some nice mist filtered light over a ramsons carpet and also deeper into the wood.

The Ransoms whilst in full flower at the wood edges were only beginning to flower in some parts of the wood where beech trees had leaf flushed well before the other canopy trees of lime and ash.

In the scowles where yew forms the understorey then it's the domain of bryophyte communities and just a few vascular plants.

It did appear to my eyes that where a canopy gap allowed morning sunlight onto the woodland floor there was a noticeable increase in woodland plants.

The light all too quickly became too harsh for effective photography and the remainder was spent investigating the wood for less common plants and enjoying the chorus of bird song.

April round up of woodland trips.

Conventional wisdom suggests that March weather influences the flowering times of spring flora and the Met Office climate maps indicates that March 2018 weather wasn't the best.

Copyright https://www.metoffice.gov.uk/climate/uk/summaries/anomacts

Copyright https://www.metoffice.gov.uk/climate/uk/summaries/anomacts

I'm fairly confident that the weather in April has also been been far from optimal. So here follows some photography trip reports and phenomenological observations on leaf bud and flowering.

Blackmill woodlands SAC

Blackmill woodlands Special Area of Conservation had been on my 'to visit' list for a while, so when an opportunity to visit friends in South Wales arose a detour was made for a quick visit. The wood was sited on a valley hillside underlain by Carboniferous coal measures on the southern outcrop of the South Wales coalfield. Some of the the oaks displayed various stages of leaf bud and leaf flushing although some trees were still in winter dormancy. The SAC notification is for "Old sessile oak woods with Ilex and Blechnum in the British Isles" and all the flora boxes were ticked for that designation to hold. Other flora seen in the wood were bluebells nowhere near flowering, a solitary patch of wood anemones were in flower and so was wood sorrell and carpets of bilberry.  The grasses present were still to develop inflorescences so no positive ID was made and the bryophyte cover noted but time didn't allow further investigation.

Bilberry and contorted oaks.

The erection of exclosure fencing around the wood perimeter had reduced herbivore grazing and the presence of saplings indicated holly and rowan were naturally rejuvenating.

Fallen deadwood.

There was also a noteworthy quantity of standing and fallen deadwood present. It was an all too brief visit and a future visit will be made to investigate further.

The next wood visited was a more local one underlain by lower Devonian sandstones and mudstones. Wind and rain limited photography ambitions to a relatively sheltered area of outsized small leaved lime (tilia cordata) coppice stools suggestive of a great age and an emerging bluebell (Hyacinthoides non-scripta) carpet. The small leaved lime, sweet chestnut and oaks were just starting leaf flush.

The third wood visited was in the Wye Valley Woodlands SAC in the upper gorge and underlain by Carboniferous limestone. Heavy rain preceded the visit and the wood was relatively sheltered from a cool northerly wind, the beech trees were in leaf so the first area visited was one where mosses cover the top of a substantial limestone pillar in the gorge.

Whitebeams (Sorbus spp) were conspicuous on cliff edges and ledges with their distinctive pale upright leaf buds and flushing leaves.

Elsewhere the wildflowers in bloom included early purple orchids (Orchis mascula), bluebells, wood anemones (Anemone nemorosa), wood spurge (Euphorbia amygdaloides) and ransoms (Allium ursinum) were just coming into flower.

The fourth wood visited was a local woodland underlain by Carboniferous limestones and sandstones with scowles workings. Nearly all the common flora associated with ancient woodland was present and flowering including two separate colonies of Herb Paris (Paris quadrifolia).

An outsize beech coppice stool hosted wood anemones as epiphytes.

A canopy gap allowed some light into the scowles and illuminated the epicormic branches on a beech tree.

That was April and the promise of ramsons and bluebell carpets in May.

Spring woodland flower recce.

A weather forecast of light wind and leaden skies favoured a recce for signs of spring flowers in two local woodlands: one a scowles woodland ~200m a.s.l and the other a Lower Wye Valley woodland ~100m a.s.l. The scowles woodland has gentle slopes underlain by Carboniferous limestone and shales with calcareous soils whilst the Wye valley wood is on a steep slope underlain by Devonian sandstone, mudstone and quartz conglomerate with a range of soil pH from acidic to mildly calcareous.

Ransoms carpet

The scowles woodland flowering was disappointing with only the odd primrose (Primula vulgaris) and carpets of dog's mercury (Mecurialis perennis) in full bloom, sadly dog's mercury is the most unphotogenic of spring wildflowers. Although carpets of ramson (Allium ursinum) leaves hinted at some potential for a future visit later in spring.

An oddity was the scarlet elf cup (Sarcoscypha cocinea) fungus which normally appears in February was still evident in the 1st week of April.

 The Wye Valley wood provided more floral interest with lesser celandine (Ficaria verna), primroses, dog's mercury (Mecurialis perennis), early dog violets (Viola reichenbachianas) and wood anemones (Anemone nemorosa) in flower. Wood sorrel (Oxalis acetosella), bluebells (Hyacinthoides non-scripta), lords and ladies (Arum maculatum) and ransoms were not in flower.

The wood anemones provided the necessary photographic inspiration. and a welcome break in the cloud allowed sunshine to briefly illuminate the woodland and an image made with some warmth to finish the trip.

Both woodlands had west facing aspects, the difference in flowering between the two woods is possibly due to the ~100m height difference with marginally colder temperatures on the more exposed and elevated scowles woodland and/or the prevalence of drier and warmer soils in the Wye Valley wood on steeper slopes.

The first day of Spring, the 'Beast from the East' and Storm Emma.

The weather for the 1st day of meteorological Spring makes for grim viewing with much of the UK gripped by a blast of air from Siberia and Storm Emma arriving from the South West.

The Brecon Beacons

 

Windchill

The Cairngorms in Scotland

screen shot from https://www.metoffice.gov.uk/public/weather/mountain-forecasts 

screen shot from https://www.metoffice.gov.uk/public/weather/mountain-forecasts

screen shot from https://www.metoffice.gov.uk/public/weather/mountain-forecasts

Definitely a day to spend by the fireside and watch the carnage unfold on the 24hr news.

Asturias trip report - 2

Next up on the itinerary was a stay at the Hotel rural Los Riegos in the Redes Natural Park run by two biologists : Sergio and Paloma. Their knowledge, guidance and insight was invaluable, which meant we undertook some excursions that otherwise would have been overlooked and consequently we extended our stay from 2 to 4 nights. After unpacking there was time for a late afternoon excursion and enquiring about a suitable walk in old woodland with spring flowers, Paloma recommended one and provided a map.

Veteran beech pollards

The walk was along old trackways in places lined with beech pollards, through predominantly beech woodland. The size of some pollards and coppice stools indicated a great age to the trees and a long history of woodland management. Natural regeneration was evident with a mix of age ranges of saplings to young trees and in places dead wood was being conserved as a habitat resource, the woodlands appeared to be managed for conservation too.

Beech woodland

The trees provided a habitat for communities of bryophytes and lichens, that might interest a specialist.

Some of the woodland flora was familiar from the UK.

Wood Sorrel (Oxalis acetosella)

Whilst other flora was not so familiar and Dog's tooth violets once again put in an appearance.

Hollow-root is classified as a neophyte in the UK.

Hollow-root (Corydalis cava )

It was a surprise to stumble upon St Patrick's Cabbage in a beech wood ~1,200 metres asl, the first indication was a group of emerging plants and then an actual specimen ready to flower. St Patrick's cabbage is part of the Lusitanian flora an enigma in plant distribution.

St Patrick's cabbage (Saxifraga spathularis)

St Patrick's cabbage (Saxifraga spathularis)

It was a good interesting walk and did not require a huge amount of imagination to see the potential for Autumnal colour.

The next day a walk was selected for its geology, geomorphology and scenery, starting from Caleao to the Desfiladero de los Arrudos.  Surrounding Caleao are a patchwork of small fields that appeared to be farmed in a traditional manner, some fields were being manured.

A landscape of traditional small scale farming

A trackway of some age.

View over farmland to the outer gorge cutting through limestone/dolostone lithologies

Downstream of the gorge is an extensive alluvial fan of boulders, many imbricated and deposited when the stream capacity of the palaeo-Arrudos dropped exiting the gorge. The size of the boulders indicate an event(s) where extremely high volumes of water flowed through the gorge. The boulder deposit had subsequently been colonised by woodland with many trees pollarded or coppiced.

One interesting flower was Angel's Tears, a native daffodil whose distribution seemed to be intimately associated with the underlying bedrock geology.

Angel's Tears (Narcissus triandrus)

In the main gorge there was compelling evidence for comparatively recent rock fall debris free from mosses, overlaying older rock fall debris colonised by mosses.

Rock fall debris chronology

The main gorge is formed from the Arrudos cutting down through steeply inclined beds of sedimentary rocks, predominantly almost pure quartz sandstones with occasional beds of shale. The depth of the gorge and the contrast between the gorge sides with ragged outcropping beds on one side and 'smooth' bedding plane surfaces on the other, is dramatic and visually impressive.

Desfiladero de los Arrudos - highly inclined bedding planes

Desfiladero de los Arduous

Outcrop of intensely fractured quartz sandstone - possibly associated with a fault/thrust plane?

The excursion up into the Desfiladero de los Arduous was good and it was another location that would be best visited in the Autumn.