The ecological integrity of ancient woodlands
Wood anenome
Ancient woodlands are mapped in England and Wales on the assumption of continuous tree cover since 1600 AD, 1750 AD in Scotland, but there has been no systematic study of their ecological integrity other than to differentiate between those having predominantly native tree species compared to those replanted often with non-native conifer species. There is a characteristic of undisturbed ancient woodland that differentiates it from recent secondary woodland, its singular species diversity, and which is a measure of its ecological integrity
Last August, I described my protracted observations of wild nature, the chronology of flowering of native wildflowers in coastal slope grassland, and the fledging in coastal nesting colonies of sand martins (Riparia riparia) and fulmars (Fulmarus glacialis) (1). It was evidence of the intrinsic value of nature being played out in the absence of human domination. The joy at the wonder of that nature has its seasons, and so the sand martins had made their long journey back to Africa by the end of September, the fulmars had returned to their life out at sea, and the flowering season had wound down in the coastal grassland.
Welcome returns
Fulmars were the first to make a reappearance, five returning in early December to the sandstone ledges of West Cliff, Whitby, but then disappeared. A week or so later, 28 had turned up. They reached a peak of 42 in January, and then all disappeared in mid-February, with 35 returning at the end of the month. There have been fluctuations between 1 and 39 since then, a count in early May showed only 6 when the most recent count was 23. I’ve given up speculating on the significance of these vacancy periods.
As would be expected from the chronology established from last year, coltsfoot (Tusilago farfar) and celandines (Ficaria verna) were the early flowerers in late March to appear in the coastal slope grassland on West Cliff, followed shortly afterwards by scurvy grass (Cochlearia officinalis) on the cliffs. Then in mid-April the distinctly different fertile and vegetative stems of field horsetail (Equisetum arvense) appeared on the grass slope, followed by ribwort plantain (Plantago lanceolata) and the small white flowers of pepperwort (Lepidium campestre). The warm spring has advanced a few flowerings, so that birds foot trefoil (Lotus corniculatus) and kidney vetch (Anthyllis vulneraria) started early and are flowering profusely now. Northern marsh orchid (Dactylorhiza purpurella) are flowering in the seepage, and there are lots of buds of common spotted orchid (Dactylorhiza fuchsia) some of which are flowering.
It may be that the sand martins anticipated the warm spring and its explosion of flying insects, as they had turned up on a sunny day at the end of April, their cheery chatter accompanying a spectacular flying display. The group, which defies accurate counting but must be over 30, has been visiting in turn the three nesting colonies in the sand lens of the soft cliffs above Upgang beach to the west of Whitby (see a video (3)). I observed on a return that there are two smaller colonies above a slump between the first and second colonies that I hadn’t noticed last year. There aren’t many nest holes in these, and the entrances to the holes are small, but I sat and waited and eventually the sand martins turned up and started exploring them as well. As with the other locations, I often saw birds go in to holes, sometimes two in quick succession, and I am sure I saw four come out of one.
Undisturbed self-assembly
A few years ago, I came across a secondary birch woodland of 3.3ha at the northeast corner of Ugglebarnby Moor, an ungrazed registered common (2) and have returned repeatedly in spite of it being species poor compared to the ancient woodland in parts of Sneaton Forest a few miles away (4). What draws me back is the evident undisturbed self-assembly of this canopy woodland of mostly birch (Betula pendula) with some rowan (Sorbus aucuparia) willow (Salix spp.) holly (Ilex aquifolium) and honeysuckle (Lonicera periclymenum). I have found only four oaks (Quercus spp.) one reaching the canopy and three youthful oaks, none of which are at seed-bearing age. Most of the willow and some of the birch is multi-stem. A few of the multi-stem willows have slumped with age, causing a chaotic scene, which is added to as early senescence in the birch has kicked in and branches have broken off. Live birch has shield lichen (Parmelia sulcata) a foliose lichen of flat, leaf-like lobes, whereas the dead birch has birch polypore fungus (Fomitopsis betulina) hoof fungus (Fomes fomentarius) and blushing bracket (Daedaleopsis confragosa).
The ground layer is uncompacted, soft and springy. It has only wood sorrel (Oxalis acetosella) and stitchwort (Stellaria holostea) amongst woodland wildflowers, but there is bramble (Rubus fruticosus) masses of Lady fern (Athyrium filix-femina) and patches of hard fern (Blechnum spicant) as well as wood sedge (Carex sylvaticum) seemingly regimented rows of tussock sedge (Carex stricta) and hairy woodrush (Luzula pilosa). Mosses include bank haircap (Polytrichum formosum) and hypnum moss (Hypnum cupressiforme). There are a few patches of bilberry (Vaccinium myrtillus) and some distressed and dead gorse (Ulex europaeus) that are remnants of the heathland habitat of the moor. The dead gorse hosts the brightly coloured yellow/orange brain fungus (Tremella mesenterica) a parasitic fungus that feeds on wood-rotting fungi (5).
What I have also noticed are the deer scrapes throughout the woodland, areas where the leaf litter is scraped away and the bare area used as a resting place, or for territory marking. Add to this the chewed state of young hollies, the fraying of bark on young tree saplings, and the well-worn narrow trails with characteristic hoof marks (pointed at the front) impressed in the muddier stretches, then it really is roe deer territory. I feel it as I walk around even though deer sightings are rare. That atmosphere of wildness is also evident from the birdsong, and was added to when I discovered a badger latrine in the wood in mid-April. I had passed an area of disturbed ground that had pits that looked like snuffle holes where badgers had been rootling for food, such as insects, earthworms and plant tubers. However, on the way back past it, I looked closer and saw that a number of the pits had fresh faeces and thus it was a latrine. I looked around for trails that would take me to a badger sett, but none led to one. I checked this badger latrine a month ago, and although I knew where to look, I couldn’t at first find it. While the latrine area had got larger – an oval shape 5m by 3.5m - it was less frequently used as there was only one hole with excrement visible, and so was less obvious. On a subsequent visit a couple of days ago, the latrine area had expanded again and many of the new pits had excrement.
Instinct for enquiry
I had first come across a badger latrine in Great Wood in Sneaton Forest in April last year. I had noticed an area at the base of a large oak tree where the bluebells, wood sorrel and young ferns had been trampled down and where a spaced series of 10-15cm diameter shallow holes had been dug in the leaf-mould enriched soil. Most of the holes had faeces at various stages of decomposition. I guessed what it was, learning later that these latrine sites are typically found at the boundaries of their territories (6). The badger setts I was aware of in Sneaton Forest were on the other side of Little Beck in this steeply sloped valley woodland, too far it seemed for their use of this latrine. However, on a subsequent search I found badger setts 50m to the west of the latrine.
In discovering these badger latrines, I had
found that I had been following in the footsteps of Eileen Soper and her
instinct for enquiry. I dropped into Pannett Art Gallery in Whitby in early
February and came across an exhibition of Soper’s sketches and water colours
of badgers (7,8). There was also a hand-drawn annotated map of a badger colony
showing topography, the location of badger setts and paths, significant trees,
and two latrines (9). It was labelled “map of the dell”. A version of
this map was used in her book entitled When Badgers Wake, published in 1955
(10) in which she described the behaviour of a colony of badgers near her home
in Hertfordshire over four years of consecutive watching, starting in April
1951. Soper was fascinated by wildlife and, in particular, by the badgers
living in the nearby fields and woods (11). She would spend entire nights
camped outside, immobile for hours, watching badger families play, hunt and
bond. The book has a description of the features in the location of the badger
colony, and which can be seen in the map (12):
“The dell, which had probably been a marlpit at one time, had a steep chalk
cliff about twenty feet deep at one end, and shelved down gradually to become
level with the field at its western extremity. Above the deepest part of the
dell was a flat spinney of cherry and other trees, with a ground cover of
dog's mercury and bluebells. There was also a patch of wild allium: this I
noticed was untouched, but there were many places where the badgers had routed
for bluebell bulbs. In the spinney, a few yards from the main sett, was a
sprawling ash worn smooth with frequent use, for its low branches were well
adapted to the badgers' needs as a playing tree. The dell might have been made
for badgers. Nowhere among other setts I have visited have I found a situation
that lent itself so completely to the needs of a badger colony"
Varied dispersal ability
I found rowan and oak and seedlings in the birch woodland on Ugglebarnby Moor during a recent visit, the oak seedlings appearing larger the nearer to the edge of the woodland. There are some individual rowans of fruit bearing size and oak trees of acorn-bearing size on the Moor outside of the birch woodland. It is likely that the rowan seedlings have arisen from birds eating the rowan berries and pooping the seed out in the woodland. Holly would have arrived in the same way. Blackbirds or jays have taken acorns from the moorland oak trees and cached them in the birch woodland, a process of hiding seeds as food for later consumption. The occurrence of these oak seedlings could, if they thrive, indicate a trajectory of change for the woodland as the oaks develop into a dominating presence in the canopy
It’s hard to say when, if at all, other woodland species will turn up (13). Their arrival in the birch woodland will depend on the varied dispersal ability of their seed, whether they are windblown, pooped out by animals or birds, carried on fur and feathers, deposited by water flow, or even transported by ants (see Table 2 in (14)). As I will explain, ancient woodlands are repositories of native woodland plant species. Unfortunately, the nearest areas of ancient woodland as a source for the birch woodland are over 1km to the east or west, and over 2km to the south, a considerable distance when many of the species in ancient woodlands are relatively immobile in terms of redistributing over even a few metres – they are poor colonisers (14,15).
By definition, ancient woodlands are where there has been continuous tree cover since at least 1600 AD (16,17). If they have not been grazed by livestock or managed and extracted, their soils will be undisturbed with an accumulation of decaying leaves and wood, and where an extensive network of roots and complex communities of plants, fungi, insects and other microorganisms have developed (18). So far, there are no plant species that have been found exclusively in ancient woodland, but there are a number of species that tend to occur in ancient woodlands that are less commonly found in more recent woodland. These Ancient Woodland Indicator species were first determined in the 1970s when a method was proposed to assess the floral significance of woodlands based on a simple count of a selected list of species (15,17). The species chosen were those that are especially associated with woodland conditions, but which exhibited a poor colonizing ability either because of poor dispersal; poor ability to survive in the dryer and more exposed conditions found outside woodlands; because new woods have unsuitable modified soils from land use; or the specialised niches are lacking that take many years to evolve. Ancient Woodland Indicator species were formerly more widespread, but they have become isolated by woodland clearance and fragmentation.
I am always looking for a new woodland to walk
I had been walking the Cinder Track last August, a disused railway line between Whitby and Scarborough, when I noticed a small trail leading into a band of high canopy woodland that ran along the southern side of the track. Once inside, it looked precipitous to go any further, as the woodland occupied a narrow but deep valley. It seemed sensible to check a map and come back, and that is when I discovered I had set foot in the eastern end of Cock Mill Wood, part of a 17.4ha band of ancient woodland that stretches westward for 1.5km towards the River Esk and descends 25m to Stainsacre Beck at the bottom of the valley (19). It was thus with some anticipation that I returned a few days later. It was a deep hole (see the hillshade LiDAR map of the wooded valley (20)). By luck, I took a trail that got me to the only public path down, an old, rock-paved route that eventually reached a small footbridge at the level of the beck. I entered the beck near the footbridge and was able to get some way along it on the sand and stone bed before I would have to start paddling. I explored various trails around there, finding a stand of hornbeams (Carpinus betulus) of various ages, an unusual find since its native range is thought to be confined to SE England – it was likely the older trees I saw had been planted there (21).
The wood had a monumental feel from the depth of the valley and the size of the trees. I saw no management of the woodland, but plenty of fallen trees and deadwood. There were many big oaks and ash (Fraxinus excelsior) as well as birch, elm (Ulmus spp.) holly, and field maple (Acer campestre). Some ground areas were covered in either pendulous sedge (Carex pendula) or woodrush (Luzula sylvatica) and there were various clumps of wood millet (Milium effusum). It was difficult to say what woodland spring flowers there would have been, amongst which would have been the Ancient Woodland Indicator plants, as there was little evidence at that time of year.
On subsequent visits during the autumn and winter months, I found a way to descend directly down to the beck, some of it on deer trails, but mostly finding my own route on the soft, springy, uncompacted woodland floor. It was an immersive route that showed me the pendulous sedge growing in downslope flushes. Sometimes, there were patches of the much smaller wood sedge (Carex sylvatica) by its side, and large patches of woodrush where it was drier. Looking up, I could see that the canopy had yellows and peach from the late turning and fall of leaves from wych elm (Ulmus glabra) and hornbeam. There were the end of season leaves of dog’s mercury (Mercurialis perennis) wood sorrel, woodruff (Galium odoratum) golden saxifrage (Chrysosplenium oppositifolium) and dog violet (Viola riviniana). I found glue fungus (Hymenochaete corrugata) sticking small dead branches onto hazels (Corylus avellana) a sign of undisturbed woodland (22). Other fungi were dead moll’s finger (Xylaria longipipes) turkey tail (Trametes versicolor) and coal fungus (Daldinia concentrica). There were masses of thalloid liverwort (Pellia epiphylla) along the earthen banks of the beck, the mosses bank haircap (Polytricum formosum) and common feathermoss (Kindbergia praelonga) and wood horsetail (Equisetum sylvaticum) in damper areas.
In November, I found a way into the midsection of the band of ancient woodland, and where it had probably turned into Larpool Wood from Cock Mill Wood (19). I could hear Stainsacre Beck below, and which became the goal. There were similarities in masses of pendulous sedge, holly, wood sedge, ferns, and the leaves of woodruff, wood sorrel, golden saxifrage, and bugle (Ajuga reptans) and the yellowing leaves of hazel, but I also unexpectedly found some spurge laurel (Daphne laureola) an evergreen small shrub that flowers in early spring. The beck became louder as I descended and then I finally saw it, but I wasn’t expecting to see the sandstone cliff face down to the water’s edge.
By February of this year, things had begun to move in both locations. The new leaves of bluebells (Hyacinthoides non-scripta) cuckoo pint (Arum maculatum) dog’s mercury, and wild garlic (Allium ursinum) had appeared. Minute red flowers were developing alongside catkins on the hazels, and new leaves were appearing on honeysuckle. A few primroses (Primula vulgaris) were in flower. A month later, in March, there were masses of wood anenome (Anemone nemorosa) in flower, as well as celandines (Ficaria verna) dog’s mercury, stitchwort, moschatel (Adoxa moschatellina) dog violet, and primrose, and the bracts of golden saxifrage had turned yellow. New leaves were appearing of bugle, wood sorrel, valerian (Valeriana officinalis) and meadowsweet (Filipendula ulmaria). A first bluebell flowered in early April, and the fiddles of new growth were appearing on ferns. A wild cherry (Prunus avium) was flowering. Bugle, woodruff, woodrush, pendulous sedge, wood sorrel, wood speedwell, wild garlic, and wood sedge started flowering later in April, and there were more bluebells. At the end of April, the wood anemones were going over, but flowering early purple orchid (Orchis mascula) had appeared; red campion (Silene dioica) herb Robert (Geranium robertianum) and goldilocks buttercup (Ranunculus auricomus) started flowering; and the leaves of wood avens (Geum urban) and enchanter's-nightshade (Circaea lutetiana) had appeared. Many trees had put on new leaves, such as ash, elm, oak, alder (Alnus glutinosa) field maple, hornbeam, birch, and hazel, as well as the shrub guelder rose (Viburnum opulus). Towards the end of May, wood avens was flowering and the leaves of broad-leaved helleborine (Epipactis helleborine) had appeared. At the beginning of June, figwort (Scrophula nodosa) yellow pimpernel (Lysimachia nemorum) wood melick (Melica uniflora) guelder rose, honeysuckle, and sanicle (Sanicula europaeus) were in flower, and meadowsweet was in bud. Both locations in the woodland are definitely roe deer territory, with scrapes, trails, and chewed holly.
Evident significance of the species
The stunning display of wood anemones I had seen, along with all the other woodland wildflowers, were what I could have hoped for from an ancient woodland. I checked my observations of over 60 species in Cock Mill and Larpool Woods with a compendium of lists of Ancient Woodland Indicator plants (17) and found that 24 broadly qualified, including wood anemone, wild garlic, moschatel, bluebells, woodruff, golden saxifrage, and wood speedwell (23). Any one on its own would not be indicative of an ancient woodland, but the larger the number, the more persuasive it is. I also checked to see what species records were available for the band of ancient woodland on the National Biodiversity Network Atlas, a repository of sightings in the UK, and found entries for two locations, one from August 1998 with 70 flowering plants a bit further west from my entry in to Cock Mill Wood (24) the other from July 2019 of 37 flowering plants near my entry into Larpool Wood (25). I was pleased that there was good congruence between my observations and those recorded.
Given the evident significance of the species content, I searched whether that band of ancient woodland had any recognition. It turned up obliquely in a sustainability appraisal report from 2016 for an extension to a Waste by Treatment and Transfer Facility in Whitby under a Minerals and Waste Joint Plan for York, North Yorkshire and North York Moors National Park (26). A table in the report noted that there were five Sites of Interest for Nature Conservation (SINC) within 2km of the waste station, one of which was Cock Mill and Larpool Wood - Stainsacre Beck (NZ90-01) that was 875m to the south of the facility. The report judged that there was no risk from the extension. SINCs are a non-statutory designation of areas by local authorities on the basis of what are priorities for nature in their area (27). I searched for any facts on the SINC, and found that information on SINCs in North Yorkshire was not freely available, being held by the North and East Yorkshire Ecological Data Centre, part of a charitable trust to which a fee is payable to view the ecological data for a specific SINC (28). Nonetheless, I did find two useful documents.
The Scarborough Local Biodiversity Action Plan from 2005, which covered Whitby, notes that the main areas of significant woodland occur on the sides of valleys that have been difficult to use for any other purpose (29). It observes that this is especially the case around Whitby, which has “some of the best woodlands within the plan area. In particular the Larpool and Cockmill Woods have a diverse flora”. Only 10 sites had been designated as SINCs primarily for their woodland interest within the plan area, but only five sites covering ~24.5ha could be considered significant ancient semi-natural woodland. It did not identify these SINCs, but it does say that it was mainly Ash/Oak woodland with small areas of wet woodland. Brief descriptions and species accounts were given for these types of woodland. There is an admission that information on the native woodland resource in the plan area is very sketchy, difficult to interpret, and much in need of updating. Annoyingly, while it is alleged in the Plan that SINCs are shown on the Scarborough Borough Local Plan map that can be viewed online, that is no longer the case. I was able to obtain a copy of the map from a local naturalist society that showed some of the SINCs around Whitby, and which included Cock Mill and Larpool Wood - Stainsacre Beck SINC (30). The boundary of the SINC primarily follows the boundary of the ancient woodland on its N side, and for the most part goes along the S boundary of the ancient woodland as it follows the westward course of Stainsacre Beck. However, it then excludes the ancient woodland then shown below Stainsacre Beck further westward and on as it joins Cock Mill Beck and until it reaches Glen Esk Road. This exclusion is likely because that portion of ancient woodland, and which includes Glen Esk Wood, is within the North Yorkshire Moors National Park boundary (see (31)). I estimate the area of the SINC to be 11.9ha.
Some of the most natural habitat in the county
Of more interest were the guidelines for site selection of SINCs in North Yorkshire (27). The guidelines observe that ancient semi-natural woodlands In North Yorkshire are generally uncommon. However, they represent “some of the most natural habitat in the county, often with a high diversity of plant and animal groups”. The document also gives descriptions and species accounts for those woodland types mentioned in the Scarborough Biodiversity Action Plan, and relates them to the woodland communities in the National Vegetation Classification system (NVC). It notes that the principal NVC woodland community dominated by ash with a variety of other tree and shrub species is the W8 (Fraxinus excelsior - Acer campestre - Mercurialis perennis woodland (32)) community. It says it is the second most common woodland type in North Yorkshire, and the majority of it is located within ancient woodland. A number of selection criteria are given in the guidelines for woodland SINCs based on the attributes of the woodland: the diversity criteria is based on the number of recorded vascular plant species, noting that this also reflects habitat diversity; and for the naturalness criteria, it is the number and cover of Ancient Woodland Indicator species. The Guidelines provides tables of these indicator species in North Yorkshire for neutral to calcareous woodlands, acid woodland, and wet woodland. Again, I compared my species observations in Cock Mill and Larpool Woods with these tables, and found that 30 were shown as indicator species, some appearing in more than one woodland type: 21 appeared on the list for neutral to calcareous woodlands, seven for acid woodlands, and 13 for wet woodlands (23). My scores for species counts in neutral to calcareous woodlands and for wet woodlands exceeded the thresholds required for SINC designation of 12 and 10 respectively (see Guideline Wd3 in (27)).
I have no expertise in matching my species observations to the various woodland communities in the NVC (32). However, there is a program which can be downloaded that can. The Modular Analysis of Vegetation Information System (MAVIS) was developed by the UK Centre for Ecology & Hydrology, and which assigns vegetation data to a number of different classification systems (33). They include the Countryside Vegetation System (CVS); the NVC; the CSR model classifying British vegetation in terms of three established growth strategies: competitors, stress-tolerators and ruderal species; the proportion of species in the vegetation data that fit with different biogeographical areas; and the overall Ellenberg scores for light, fertility, wetness and pH, these scores indicating the preferences for the various environmental conditions under which the group of species is growing (34). I ran both sets of observations, Cock Mill and Larpool Woods, separately through MAVIS and got very similar results.
There are 100 vegetation classes in the CVS, a system that differs from the NVC in that they were derived from random observations in the countryside, rather than the NVC which is based on locations selected on the basis of the homogeneity of their vegetation (35). Thus, the NVC is primarily designed to describe semi-natural vegetation whereas the CVS covers as well the more disturbed wider countryside and which includes agricultural land. MAVIS came up with CVS #39 for both Cock Mill and Larpool Woods, which the entry in the list of CVS says is Fertile wooded streamsides, this lowland woodland usually having ash as a canopy species, with a ground cover of dog’s mercury, enchanter’s-nightshade, and wood speedwell, and with the likely NVC being W8 (35). MAVIS returned aggregate Ellenberg scores for the species observations of both Cock Mill and Larpool of low for light level (5, 4.8) medium for moisture, a pH near neutral, and high fertility. It also showed that greater than half the species were from the European Temperate biome.
The evolutionary adaptive strategies of plant life histories
I have come across the CSR Plant Strategy Model before, but never got to grips with it. The model is an attempt to explain the evolutionary adaptive strategies of plant life, and assumes that constraints on the accumulation of plant biomass are principally controlled by stress and disturbance (36,37). Stress refers to factors that limit growth, such as drought, shade, low temperature and nutrient limitation. Thus, plants that have evolved to withstand continuously low productivity imposed by low light, moisture or nutrient stress are Stress tolerators (S). The second constraint is disturbance associated with partial or total destruction of biomass resulting from phenomena such as fire, trampling, cultivation, flooding and herbivore activity. Those plants that can exploit severely disturbed, productive habitats are the Ruderals (R). The third primary strategy is where neither stress or disturbance are present, or are at a low intensity, as factors limiting plant growth. Under this strategy, the composition of a plant community is determined by competition between species for resources - the Competitors (C). It is characterised by the ability to secure resources through the constant readjustment of the spatial distribution of roots and shoots. In reality, plant species show a range of life strategies that are combinations of the three primary strategies at different levels, and which is often represented within a triangle with the points being where the association is strongest with one of the three primary strategies. To simplify this, the combinations for each species have been turned into a score under the three primary strategies where 1 indicates the least association with a strategy, to 5 indicating the strongest association with a strategy. MAVIS uses this data to compute a mean Competitor, Stress-tolerator and Ruderal score for a list of species supplied (34).
My observed species lists for Cock Mill and Larpool woodlands showed the strongest association with the Stress-tolerator strategy of plant growth (S=3.05, 3.00). The association of the species showed an intermediate value for the Competitor strategy (C=2.62, 2.58) and the Ruderal strategy had the lowest association (R=1.73, 1.88). I re-ran MAVIS with solely the 28 species observations from Cock Mill and Larpool Woods that were indicator species for ancient woodland in North Yorkshire (22,26). While the association with the Ruderal strategy (R = 1.78) was little changed, there was a decrease in association with the Competitor strategy (C = 2.04) and an increase in association with the Stress-tolerator strategy (S = 3.74). I also identified the individual Ellenberg light scores for these indicator species and came up with a range of 3 to 6, with a mean score of 4.6 (22) slightly lower than the average Ellenberg light level for the complete species observations in Cock Mill and Larpool Woods of 5.0 and 4.9 that was returned by MAVIS. Ellenberg light level scores range from 1 for plants in deep shade, none of which exist in Britain, to 9 for plants in full light, found mostly in full sun (38). Plants with a score of 3 such as woodruff and dog’s mercury on my list of indicator species are shade plants where there is less than 5% relative illumination; pendulous sedge, bluebells and primroses on my list have a Ellenberg light level of 5, which indicates semi-shade where there is more than 10% relative illumination, but seldom in full light (23).
I found a study that investigated the ecological properties of ancient woodland indicator plant species in eight countries across Europe, including Britain. The study showed that they tended to be shade- or semi-shade tolerant as shown by their individual Ellenberg scores for light, with a mean indicator value of 4.33 (14). They were concentrated in the mid part of the moisture gradient, as shown by their Ellenberg score. It also found that 24% of ancient woodland species were dispersed by ants, such as wood sedge, wood anemone, and wood speedwell (14) species that appear in my observed list of indicators in Cock Mill and Larpool Woods along with five others that are also dispersed in that way (23). A similar number on my indicator species list were dispersed by being pooped out, a lesser number by being windblown or actively dispersed by the plant itself, and only pendulous sedge and golden saxifrage were dispersed by water (23)(Dispersal modes for indicator species not shown in (14) were obtained from (39)). These proportions of dispersal modes perhaps indicate the overall short dispersal ability of the indicator species (14). In terms of plant strategies, the greatest association in the European study of indicator plants was with Stress tolerance and with lower associations with Competition and Ruderal. I estimate comparable values in the study with the format of the MAVIS output to be ~C=2, S=3, R=1.
It is not ours to carelessly lose
The European study would seem to confirm my findings at Cock Mill and Larpool Woods that ancient woodland indicator plants are predominantly stress-tolerators in that they will grow in shade to semi-shade, avoid disturbance, and they are poor colonisers. This has implications for our sense of their worth when it seems unlikely that our disturbed ecosystems would ever recover or be reparable to the extent that they would have the complex communities of plants, fungi, insects and other microorganisms of our extant, undisturbed ancient woodlands. As it is, threats do not just come from woodland clearance and fragmentation, but more insidiously from invasion of non-native species that can come to dominate. The Scarborough Local Biodiversity Action Plan cautioned that rhododendron was a threat to wet woodlands where it can spread aggressively and dominate the shrub layer. I have observed expanses of rhododendron (Rhododendron ponticum) and cherry laurel (Prunus laurocerasus) in areas of Cock MIll and Larpool Woods, and where the ground layer is completely bare of native woodland plants under the dense shade that these evergreen shrubs produce.
In Britain, we tend to venerate aspects of cultural landscapes, little recognising what may be an ecosystem closest to its natural condition. Primary forests world-wide are recognised to have high ecological integrity (40) but while ancient woodland areas have been mapped in Britain, there has been no systematic study of their ecological integrity, nor is there any clear way to safeguard it (41). I do not grieve that the birch woodland at Ugglebarnby will unlikely ever have the species complement of undisturbed ancient woodlands, as it has made the best of the species available to it, a level of ecological integrity of its own making, and which supports both avian and mammal species too. I marvel at Cock Mill and Larpool Woods and recognise their undisturbed self-assembly and perpetuation of a singular species diversity. It is not ours to carelessly lose.
Mark Fisher 31 May 2025, updated 9 June 2025
(1) A natural life – the self-will of existence, Self-willed land August 2024
http://www.self-willed-land.org.uk/articles/intrinsic.htm
(2) Deciduous woodland, northeast corner of Ugglebarnby Moor, a registered common, MAGIC Map
https://magic.defra.gov.uk/MagicMap.html?chosenLayers=niwtIndex&box=488744:505971:489156:506169
(3) Video of sand martins, Upgang Cliffs, 9 May 2025
http://www.self-willed-land.org.uk/articles/sand_martins_upgang_cliffs_may_2025.mp4
(4) Requiem for rewilding, Self-willed land July 2021
www.self-willed-land.org.uk/articles/requiem.htm
(5) Yellow brain (Tremella mesenterica) Woodland Trust
https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/fungi-and-lichens/yellow-brain/
(6) Guidance Licensing - Badgers - badger survey best practice, Nature Scot
https://www.nature.scot/doc/guidance-licensing-badgers-badger-survey-best-practice
(7) The Soper Collection, Pannett Art Gallery
https://www.pannettartgallery.org/whats-on/soper-collection/
(8) Badger sketch, annotated, Eileen A. Soper
www.self-willed-land.org.uk/articles/badger_annotated.jpg
(9) Map of the Dell. Sketch by Eileen A. Soper
www.self-willed-land.org.uk/articles/map_of_the_dell.jpg
(10) Eileen A. Soper, When Badgers Wake, London: Routledge & Kegan Paul Ltd, 1955
https://www.etsy.com/uk/listing/1359799425/when-badgers-wake-by-eileen-a-soper
(11) Eileen Alice Soper RMS SWLA 1905-1990, The Soper Collection
https://www.thesopercollection.org/eileen-soper/
(12) Eileen A. Soper, The Badgers Dell, in When Badgers Wake, London: Routledge & Kegan Paul Ltd, 1955 – pg. 30
https://i.etsystatic.com/38113869/r/il/80b2c8/4398815538/il_794xN.4398815538_mshh.jpg
(13) Bauld, J., Guy, M., Hughes, S., Forster, J., & Watts, K. (2023). Assessing the use of natural colonization to create new forests within temperate agriculturally dominated landscapes. Restoration Ecology, 31(8), e14004
https://onlinelibrary.wiley.com/doi/pdf/10.1111/rec.14004
(14) Hermy, M., Honnay, O., Firbank, L., Grashof-Bokdam, C., & Lawesson, J. E. (1999). An ecological comparison between ancient and other forest plant species of Europe, and the implications for forest conservation. Biological conservation, 91(1), 9-22
(15) Peterken, G. F. (1974). A method for assessing woodland flora for conservation using indicator species. Biological Conservation, 6(4), 239-245
https://www.sciencedirect.com/science/article/pii/0006320774900019
(16) Peterken, G. F. (1977). Habitat conservation priorities in British and European woodlands. Biological Conservation, 11(3), 223-236
https://www.sciencedirect.com/science/article/pii/0006320777900064
(17) Glaves, P., Handley, C., Birbeck, J., Rotherham, I., & Wright, B. (2009). A survey of the coverage, use and application of ancient woodland indicator lists in the UK
https://core.ac.uk/download/pdf/4149223.pdf
(18) Where have all the woodland flowers gone? Self-willed land August 2020
www.self-willed-land.org.uk/articles/woodland_grazing.htm
(19) Cock Mill/Larpool Woods, Ancient Woodland (England) MAGIC
https://magic.defra.gov.uk/MagicMap.html?chosenLayers=ancwoodIndex&box=488849:508342:491691:509709
(20) LiDAR mapping of
Cock Mill/Larpool Woods, Composite Hillshade Digital Terrain Model - 1m, ARCHI
MAPS
https://tinyurl.com/2pd2tw9r
(21) Hornbeam (Carpinus betulus) BSBI Plant Atlas 2020
https://plantatlas2020.org/atlas/2cd4p9h.yf
(22) Coastal temperate rainforest - in Britain?! Self-willed land June 2015
http://www.self-willed-land.org.uk/articles/rain_forest.htm
(23) COCK MILL/LARPOOL WOODS INDICATOR PLANTS - Self-willed land June 2025
http://www.self-willed-land.org.uk/articles/cock_mill_larpool_indicators.pdf
(24) Cock Mill Wood, NBN Atlas Lat: 54.4673, Lon: -0.6105
https://records.nbnatlas.org/explore/your-area#54.4673|-0.6105|16|ALL_SPECIES
(25) Larpool Wood, NBN Atlas Lat: 54.4686, Lon: -0.6121
https://records.nbnatlas.org/explore/your-area#54.4686|-0.6121|16|ALL_SPECIES
(26) Appendix 3j: Assessment of Sites in the North York Moors National Park Joint Minerals and Waste Plan. Sustainability Appraisal Report
(27) Guidelines for Site Selection, Sites of Importance for Nature Conservation in North Yorkshire 2017
(28) Local Wildlife Sites in focus – review of the SINCs network in 2022, Tim Burkinshaw, Connecting for Nature August 25, 2022
(29) Scarborough Biodiversity Action Plan April 2005
(30) SINCs around Whitby - map 2, North Yorkshire County Council 2013
www.self-willed-land.org.uk/articles/Whitby_SINCs_map2.pdf
(31) Map of Cock Mill/Larpool ancient woodland showing North Yorks Moors National Park boundary
(32) Hall, J. E., Kirby, K. J., & Whitbread, A. M. (2004) National vegetation classification: field guide to woodland. Joint Nature Conservation Committee
(33) Modular Analysis of Vegetation Information System (MAVIS) UK Centre for Ecology & Hydrology
https://www.ceh.ac.uk/data/software-models/modular-analysis-vegetation-information-system-mavis
(34) MAVIS (Ver 1.03) User Manual 2016
https://www.ceh.ac.uk/sites/default/files/Mavis-Desktop-Help.pdf
(35) Bunce, R. G. H.; Barr, C. J.; Gillespie, M. K.; Howard, D. C. ; Scott, W. A.; Smart, S. M. ; Van de Poll, H. M.; Watkins, J. W. (1999) Vegetation of the British countryside - the Countryside Vegetation System. ECOFACT Volume 1. London, DETR
https://nora.nerc.ac.uk/id/eprint/4311/1/ECOFACT1.pdf
(36) Grime, J. P. (1977). Evidence for the existence of three primary strategies in plants and its relevance to ecological and evolutionary theory. The American Naturalist, 111(982), 1169-1194
https://ecoevo.wdfiles.com/local--files/start/Grime1977.pdf
(37) Grime, J. P. (2006). Plant strategies, vegetation processes, and ecosystem properties. John Wiley & Sons
https://books.google.co.uk/books?id=xX6v45bGGlkC&lpg=PP1&pg=PR28#v=onepage&q&f=false
(38) Hill, M.O.; Mountford, J.O.; Roy, D.B. ; Bunce, R.G.H. (1999) Ellenberg's indicator values for British plants. ECOFACT Volume 2 Technical Annex. Huntingdon, Institute of Terrestrial Ecology, (ECOFACT, 2a)
https://nora.nerc.ac.uk/id/eprint/6411/1/ECOFACT2a.pdf
(39) Information about species, PLADIAS Database of the Czech Flora and Vegetation
(40) Kormos, C. F., Mackey, B., DellaSala, D. A., Kumpe, N., Jaeger, T., Mittermeier, R. A., & Filardi, C. (2018) Primary forests: definition, status and future prospects for global conservation. Encyclopedia of the Anthropocene, 2, 31-41
(41) Razzaque, J., & Lester, C. (2021). Why Protect Ancient Woodland in the UK? Rethinking the Ecosystem Approach. Transnational Environmental Law, 10(1), 135-158
url:www.self-willed-land.org.uk/articles/cock_mill_larpool.htm
www.self-willed-land.org.uk mark.fisher@self-willed-land.org.uk