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Wonderful solitude

by Shaun, 26 January, 2024, 0 comments

The end of lockdown, and the peace that came with it, was what made me want some natural solitude as the world got busy again. Having a share of a near 100-acre ancient wood should provide that given there are no public footpaths through it, a locked gate and farm land all around. It was late summer when I ‘got the keys’ and I was recovering from major surgery, so over the autumn into winter I’ve pottered and observed.  Each visit the place looks different as the leaves fall, different fungi come and go, and the wood is deluged by each storm. Storm Babet blew down the largest silver birch tree. The kids discovered it – wading through the thick brown bracken in a clearing I’d yet to explore. They had fun running along it. So far, no more have come down, and I’m glad I bought the Beech Tree wood owners insurance before the first storms hit. There is about one acre of older pine that stand majestic, almost as a guard for the younger trees beyond. We’ve re-planted our Christmas tree here. I hope it takes! Then it’s a grassy break, that allows machinery to manage a drainage dyke, across a wooden bridge and into the 4 acres of dense young birch coppice. This needs a lot of thinning out, if owt else is to grow there. The west boundary is a huge sheep field and the sun pours in. It wasn’t until my fifth visit that I managed to get through to a far corner of the plot and find another small clearing, where clearly deer had been laying on the dead bracken. I hesitate to say basking in the winter sun ….....  in Yorkshire! There’s evidence of badger setts too but none seem active. Woodcock abound and I will have to control the dog in spring. It isn’t silent but I’m surprised there isn’t a greater dawn chorus when I visit. Perhaps the buzzards and red kites are scaring smaller birds off.   I certainly hear those birds of prey about. Is this a sign of climate change or a lack of tree diversity? To help the both I’ve planted some cuttings of hazel and walnut, and a variety of seeds – conkers, acorns, sloes, sweet chestnuts, sycamore and walnut, but goodness knows if anything will germinate, or whether the squirrels have had a feast!  It was a rushed affair as I wasn’t completely recovered from surgery when I did it. There are lots of plots within the greater wood and I’ve met many of my neighbours, who are all very friendly. At least one is an outstanding wildlife expert and I’m sure there’s lots to learn from them.  I don’t have great plans as yet other than increasing the diversity of trees. A fig tree at home next to a west facing wall does really well.   Will the west facing aspect enable similar here?  There seems to be some quite large structures within the wider wood. On my plot, there’s a small hut and I don’t have plans for anything more. I just want to observe for a year, open up a couple of paths through the jungle and create somewhere flat to camp. There is wonderful solitude and the dog loves it – even though she has come back with ticks. Neighbours have told me their 'tick stories' and I’ve noted that they wear thick overalls and boots.   Probably best  if I string up a hammock to watch the sunsets!  
Woodlands web updates : 27

Woodlands web updates : 27

by The blog at woodlands.co.uk, 16 November, 2023, 0 comments

Tree survival and drought. Researchers at the University of California have been working on a method that helps predict whether forests / woodlands can survive periods of drought.  As climate change is altering patterns of snow and rainfall, so periods of drought are likely to become more common. Forests are important in terms of carbon sequestration, that is, they take up carbon dioxide from the air and convert it into sugars, starches etc that are stored in the leaves, branches, stems and roots.  However, in order to assimilate and convert carbon dioxide (in photosynthesis), trees (indeed all plants) need a supply of water.  When water is limited, trees need to make use of their reserve materials.  Just as we make use of body reserves of fat and glycogen when food / diet in inadequate. However, reserves can only sustain a tree for a finite period of time.  If drought persists, the tree reaches a ’tipping point’ and it will die.  The researchers studied a forest in the Sierra Nevada that experienced a period of drought between 2012 and 2015.   During this period, millions of trees died.  The team recorded rainfall, soil moisture and temperature in the forest AND the amount of carbon dioxide that the trees absorbed, and their reserve materials.  They found that the trees were able to maintain function / health after the onset of the drought but with the passing of time, the trees exhausted their reserves and were unable to use / convert carbon dioxide into food.  They had reached the tipping point and died.   The methodology of this study was called CARDAMON (carbon data assimilation with a model of carbon assimilation); it is hoped that it can be used to evolve strategies to enhance forest and woodland resilience in the face of climate change. Pollinators. [caption id="attachment_35902" align="aligncenter" width="675"] hoverfly[/caption] University researchers from the UK and Finland have been trying to determine the most effective pollinators of crop plants, like strawberries (and other fruits).  Plentiful and effective pollinators are needed to ensure a good harvest of the fruits. The researchers studied the pollinators at three strawberry farms through the (long) growing season for the fruit.  They adopted two approaches : They caught the insects that visited the strawberry flowers and analysed the pollen they carried in detail (pollen load and type). They also counted the number of flower visits by the different insects, (a quick way to identify key local pollinators). Many insects were identified, including :-  European drone fly :           Eristalis arbustorum Honeybee :                               Apis mellifera Levels drone fly :                   Eristalis abusivus Buff tailed bumblebee :     Bombus terrestris White tailed bumblebee :  Bombus lucorum Common drone fly :             Eristalis tenax Red tailed bumblebee :      Bombus lapidarius Early bumblebee :                Bombus pratorum Bent-shinned Morellia :   Morellia aenescens Hoverflies are true flies, that is, they belong to the order Diptera or true flies, as they have a pair of wings and a pair of halteres (balancing  / orienteering organs used when in flight). Several of the flies in the genus Eristalsis are known as Drone Flies (due to their resemblance to honey bee drones).  The larvae of Eristalis  species are commonly found in putrid / stagnant water and sometimes referred to as “rat-tailed maggots”. It was noted that pollinators also made use of the wild plants to supplement their diets, as strawberries alone cannot meet the nutritional needs of pollinators.  ‘Elsanta’ strawberries have a relatively low sucrose and protein content in both their nectar and pollen. The precise  order of importance of pollinators varied between farms.  Bee (Apis and Bombus) species  and hoverfly (Eristalis) emerged as key pollinators. The European drone fly was the most important pollinator at two of the three farms studied, evidence that hoverflies can be effective pollinators.  One farm had commercial hives of the honey bee but they were less significant than the activities of of the hoverflies and bumblebees. The abundance of a particular insect, coupled with its active period were /  are important determinants of pollinator importance.  Sawdust and plastics - a possible use?. Plastics represent a relatively new, but persistent and major form of pollution (on land, in the sea, indeed everywhere).  Whilst many plastic objects are instantly visible in the form of discarded bottles, fast food containers, many plastic pollutants are in the form of very small particles of plastics  - nano and microplastics.  The concern is that we and other organisms are taking these microscopic particles into our bodies from our food / drinking water. However, it is possible that plant materials may offer some ‘solutions’.  Water that contains micro and nano plastics can be filtered through sawdust that has been treated with tannic acid.   Tannic acid is large molecule, its molecular formula is C72H52O46 .  Tannic Acid is found in certain plant galls (swelling of trees caused by parasitic wasps) and in the twigs of certain trees, such as Chestnut and Oak.  The wood sawdust contains fibres of cellulose, combined with hemicelluloses and lignin.  Water can flow through this material by capillary action.  This plant-based filtration (known as bioCap) of plastic-laden water is capable of dealing with a wide range of nanoplastics (PVC, PET, polyethylene etc), and tests with mice suggest that the filtered water may be sufficiently free of plastic to pose little risk.  
Deer and Scotland’s temperate rain forest.

Deer and Scotland’s temperate rain forest.

by The blog at woodlands.co.uk, 6 July, 2023, 1 comments

Scotland’s west coast has a number of temperate rain woodlands / forests. They are quite rare. The remnants of oak, birch, ash, native pine and hazel woodlands are small and isolated from each other. They are noteworthy for the diversity and richness of the bryophytes (mosses and liverworts) and lichens; found in abundance on the trees, rocks and on the ground.   Sadly, such woodlands have been in decline for some time. In the past, this woodland covered large areas of the west coast of Scotland, but much has been lost over the last two thousand years.  These woodlands / forests now cover a small area, just under 5% of the land. Factors that have contributed to the decline and loss of this woodland include:- mismanagement,  overgrazing by sheep and  invasion by non-native species [such as Rhododendron ponticum]. According to recent study by Scottish Environment LINK, deer now represent a considerable threat to the woodlands.  Whilst deer are part of woodland ecosystems, when their numbers increase beyond a certain point then they become a significant problem.  Deer numbers are now at historic highs in Scotland/  Money has been made available to manage surging deer populations, for example, through the provision of deer fencing.  However, the report considers that such fencing is “both expensive and often ultimately ineffective”.  More needs to be done if deer damage is to be reduced and allow regeneration of the woodlands. Developing a community approach to deer stalking and management will be important, combined with the use of technologies such as thermal and drone surveying. A greater focus on the management of roe and sika deer, combined with the removal of Rhododendron ponticum will be needed if the woodlands are to flourish and expand. see also : https://www.thescottishfarmer.co.uk/news/23637346.soaring-deer-numbers-see-new-powers-land-managers/   [caption id="attachment_39688" align="aligncenter" width="675"] Rhododendron ponticum, these plants were growing near the River Tay.[/caption] visit https://www.instagram.com/woodlands.co.uk/?hl=en  
Revisiting hedgerows.

Revisiting hedgerows.

by The blog at woodlands.co.uk, 12 April, 2023, 0 comments

Some years back, the Woodlands blog posted various articles about hedgerows,  noting the loss of many - due to the increased mechanisation of farming in the mid C20th.  Now, there is greater recognition of the importance of hedgerows, and there are initiatives to promote the maintenance and expansion of hedgerows. But what is a hedgerow? Natural England offers a definition as follows : A hedgerow is defined as any boundary line of trees or shrubs over 20m long and less than 5m wide, and where any gaps between the trees or shrub species are less that 20m wide (Bickmore, 2002). Any bank, wall, ditch or tree within 2m of the centre of the hedgerow is considered to be part of the hedgerow habitat, as is the herbaceous vegetation within 2m of the centre of the hedgerow.  This differs from the definition in the  Biodiversity Action Plan, which included references to ancient hedges / species-rich hedges.  The definition now includes all hedgerows consisting of at least one native woody species of tree or shrub (mainly), but it does exclude bramble and honeysuckle as ‘woody species’.  According to one source, there are some 550,000km of hedgerow in England, with over 400,000 km being actively managed.  Hedgerows are an important semi-natural habitat in what is otherwise a managed agricultural landscape. They are found across the country but there are more in lowland regions. Hedgerows in the south east are associated with large fields and fewer trees, the proportion of trees in hedgerows increases as one goes north and west.   The nature of hedgerows varies across the country but all are important as : They provide a habitat, shelter (micro-climate provision) and resources for many different species (from plants to insects, birds and mammals). Hedgerows are particularly important as nesting sites for birds. They support animals that have key roles within the broader ecosystem, for example pollinators and predators of pests. They offer an important source of nectar that helps support wild bees - adjacent farmland can be a poor source of nectar Hedgerows are known to support threatened (red listed) species Hedgerows capture and store carbon (above and below ground) Hedgerows offer ecosystem services eg. mitigation of water flux and availability, landscape connectivity, soil conservation / stabilisation. A number of studies indicate that increasing the number of hedgerows would help with landscape connectivity (for example, for hedgehogs) and that planting of blackthorn and hawthorn in association with later flowering species would help support a number of wild bee species.  Expanding the number of hedgerows could have some negative effects as they might offer a home to invasive species and / or pathogens; but one study has indicated that ash trees in hedgerows suffer less impact from ash dieback than trees in forests.  To date there does not appear to be any detailed research on whether increasing hedgerow coverage would have any impact on tree disease / pathogen spread. Hedgerows, like woodlands themselves, face a number of challenges due to climate change.  Warmer winters may mean that the ‘winter chill’ requirements of some shrubs / trees will not be met; this may mean flowers and fruits fail to form properly which in turn means less food for birds, small mammals etc.  Drier summers may stress some species, trees like Beech are susceptible to drought.  Extreme weather events (like Storm Arwen) can inflict damage on hedgerow trees.  If a hedgerow is next to farmland, then it may experience drift from pesticide and / or herbicide spraying  nutrient enrichment (eutrophication) due to the use of fertilisers. Hedgerows with a diverse structure, with plants, shrubs and trees of varying ages and heights provide the widest range of niches / microhabitats for wildlife.  The inclusion of dead / decaying wood offers opportunities for various fungi, saproxylic beetles, woodlice etc.  Some hedgerows are managed / reduced with a mechanical flail (see above !!!). If this is done annually, it can result in a loss of biodiversity. Trimming should be done on a 2 or 3 year cycle; and some sections of the hedge might be left for longer " see (https://www.hedgelink.org.uk/cms/cms_content/files/76_ne_hedgecutting.pdf).  Thousands of tree and hedgerow plants are being planted to create a flood defence project at Castlehill, East Hull.   The plan is to create some seven hectares of woodland and over five kilometres of new hedgerow, as part of a flood defence project (to store floodwater east of the city).  Trees such as field maple, downy birch, English oak, and black alder are being planted along with species of willow, dog rose, guelder rose and blackthorn and hawthorn to create hedgerows and scrubland.  Other species will be allowed to naturally develop in the area and the habitat is expected to reach ‘maturity in some fifteen to twenty years. There is a citizen science project that involves surveying hedgerows.  It is organised by the People’s Trust for Endangered Species [PTES].  The Great British Hedgerow Survey guidelines can be found here : https://hedgerowsurvey.ptes.org/survey-guidelines Some times hedges offer a home to other things         
Rhododendron ponticum revisited

Rhododendron ponticum revisited

by The blog at woodlands.co.uk, 30 March, 2023, 0 comments

In the eighteenth and nineteenth century, many explorers / adventurers brought ‘exotic’ plants back to the United Kingdom. These ‘exotics’ were planted in arboreta, botanic gardens, and some in gardens.  One bush that was introduced was Rhododendron ponticum. The plant is native to the eastern and western Mediterranean, and the Pontic Mountains, hence its name). It was introduced into Britain in the late eighteenth century, by Conrad Loddiges.  It was planted in Victorian hunting estates, also on heathland areas to provide shelter for game species. Its rootstock has been used for grafting of less hardy, more colourful types.  Many Rhododendron species are a delight and an adornment to our parks and gardens, indeed many hundreds of species of Rhododendron are known (many in China and the Himalayas)*.   Rhododendron ponticum has proved to be invasive.  It is a threat to key parts of our woodland ecosystems, such as Atlantic Oak Woodland.  Atlantic oak woodland is sometimes referred to as Celtic Rainforest.  It is characterised by lichen covered trees, growing amongst a rich moss and liverwort flora.  This woodland environment is damp and humid, to which streams and waterfalls contribute. These woodlands have evolved under the influence of the Gulf Stream,  which helps keeps warm and wet the area.  In some parts of the country, the woodlands have remained in their 'ancient state', since the last ice age.  However, these woodlands were more extensive but now exist as much smaller ‘pockets’ - damaged by grazing, pollution, and ‘exotics or aliens’ like R. ponticum. When this shrub ‘invades’, it 'takes over' and the woodland floor becomes a dark and barren place. A deep shade results from the thickets of the Rhododendron.  This results in the loss of much of the ground flora so that only some shade tolerant mosses and liverworts remain.  They form a ‘mat’ of dense vegetation that is a barrier to seed germination.  Even when the Rhododendron thicket is removed, the re-establishment of the original flora is compromised.  There is also evidence that as it grows this shrub produces chemicals which inhibit the growth of other species;  this is known as allelopathy. R.ponticum has spread in many areas, mainly to the West of the country. Each flower can produce several thousand seeds, so that a large bush can produce several million seeds in year. These seeds are tiny and wind dispersed; and though not all the seeds will germinate and grow, many will and colonise an area. Even when bushes have been removed from an area and the litter layer cleared, the seeds may persist in the seed bank of the soil - allowing the species to recolonise. In consequence, follow up over a five year period is really important. Recent figures suggests that some 37,000 hectares are affected in the UK.  Though the government does make a grant available for the removal of Rhododendron, progress with its removal has been slow. In Wales, there is a project called the Celtic Rainforests Project  (YouTube video link here) that focuses on invasive species and their attempted eradication in Atlantic Oak Woodlands in Wales.  With the agreement of the landowner, the project will organise surveys to identify the scale of the problem, and then contractors to carry out the work over the period of a management agreement, at no cost to the landowner [woodlands.co.uk has groups of buyers who have agreed for their various woods to be covered by such management agreements]. Clearing an area of this plant is difficult and expensive. An  effective first treatment to eliminate R. ponticum is to drill the stems, and inject herbicide directly into the plant.  This uses a lot less herbicide than spraying, and is a selective approach.  Mabberley’s Plant-book notes that the cost of eradicating the plant from Snowdonia was £30 M and that was in 1988.  Further information about the work in the welsh oak woodlands here. The plant is also a problem in Ireland. Indeed, referring to the Killarney National Park a politician has said “nothing short of calling in the army is going to put it right.” [caption id="attachment_39688" align="aligncenter" width="675"] Rhododendron ponticum growing near to the River Tay.[/caption] Forest Research has a number of publications about the management and control of R. ponticum. * Details of the genus may be found in Mabberley's Plant-Book. With thanks to Chris Colley
December Monthly Mushroom - Purple Jellydisc (Ascocoryne sarcoides

December Monthly Mushroom – Purple Jellydisc (Ascocoryne sarcoides

by Jasper Sharp, 15 December, 2022, 0 comments

Looking out of the window as I type this month’s fungi focus, it is difficult to believe that but a few months ago we were at the tail end of a prolonged and intense heatwave and drought. Now as we plunge towards the depths of midwinter, the traditional mushroom hunting season is already well past its peak. Like heat and dryness, most fungi seem to have little tolerance for frost, snow and ice. But there’s no need to be too pessimistic that it’s all over for another year. There’s still plenty of stuff out in the woods and after several years of writing in these blogs about what can be found in any given month, as far as I’m concerned the season is never really over. “Seek and you shall find” is my chosen mantra when I head out with my camera. In fact, I perversely prefer the winter months to the brief but intense height of the season during September to November, a period that yields so many discoveries that photographing and identifying them all can be onerous and overwhelming, and when the forest floor is so dynamic it is difficult to know what species to make the subject of these monthly focusses. Winter is a great time to concentrate on the less showy side of the fungi kingdom; the crusts and the jellies and the other little things you might not notice until you actively start looking. This is the time to persevere with getting that ever-elusive perfect photo of such commonplace species as Candlesnuff Fungi (Xylaria hypoxylon), for example. It is most likely that in the process, while crouched amongst the crisp leaf litter, your eyes will wander and you’ll end up discovering something else you’d might otherwise never have noticed. Candlesnuff With this end-of-year windup for the winter, I decided to focus on a species that has just emerged over the past month that might be lingering a little longer while we wait for Spring. I’ve written before how jellies such as the Yellow Brain fungus and the various other types some refer to as Witches’ Butter manage to resist regular freezing and defrosting and can be found many months after they first emerge. To the list we might also add Jelly Ears and Tripe Fungi, but also another one I’ve not yet covered, which is the Purple Jellydisc (Ascocoryne sarcoides). These can take a variety of forms, from walnut-sized and brain-like to the more discoid example one might expect from its common name. They start emerging mid to late November, when the temperatures first start dropping, growing in clusters on dead deciduous trunks and branches – often beech but certainly not always – as if oozing from the wood. One might assume from the shape and texture that these are closely related to Yellow Brains and Crystal Brains, but whereas these other jellies are basidiomycetes (producing their spores on external structures), Purple Jellydiscs are ascomycetes (with their spores developing internally in sac-like structures called asci) - again, I’ve regularly covered this crucial taxonomic distinction, such as for example in some detail here. I would label the Purple Jellydisc a very common fungi, in that I’ve found it in every woodland I’ve ever spent much time in, although it is not as conspicuous as the other jellies. Yellow Brains, for example, seem to be appear quickly and fully formed, while Purple Jellydiscs seem to emerge small and grow slowly.  Black Witch I’m not entirely sure they are as durable as these other “true” jellies either; I’ve monitored a single growth of Exidia glandulosa, the Black Witches Butter, for a period of almost half a year, watching it dry, inflate, freeze and defrost through the seasons, but I am not entirely sure if I’ve really ever registered Purple Jellydiscs past January. These are also rather drab in the winter light too, more reddy brown than purple, and more opaque than glistening. They are consequently rather difficult to get a decent photo of, although with artificial lighting one gets a better sense of its blanched beetroot hues and jelly baby-like texture. This should all be enough for the casual nature lover to be able to look at a specimen fitting this basic description and to ascribe a name to it. As usually seems to be the case in mycology however, with the two near identical Yellow Brain species proving the point wonderfully, there are a handful of other species in the Ascocoryne genus that look pretty much exactly the same and share similar environmental niches. To prove this rather maddening point, just a few weeks back, I found a group of purplish discs growing in clusters on a fallen beech trunk that looked nothing like any other Purple Jellydiscs I’d ever found before, but they did fit descriptions of Ascocoryne cylichnium, which has the common name of the Budding Jellydisc. First Nature describes this species as “similar but its fruit bodies remain cup shaped rather than merging into a brain-like form.” So far so good, I thought, and if I didn’t have a microscope in my possession, I would have left it at that. But as First Nature also wrote, that “it can only be identified with certainty by microscopic study of the spores, which are much larger than those of Ascocoryne sarcoides”, I decided to dive in for a better look. At this point, I was also informed of the existence of a couple of further species that looked pretty much the same: Ascocoryne solitaria and Ascocoryne inflata. They could only be distinguished from one another and identified with any conviction through close microscopic scrutiny of specific structural details. Needless to say, they don’t have English common names. Anyway, to cut a long and potentially very tedious story short, I did look at my sample under the microscope and it turned out after all to be your bog standard Purple Jellydisc, Ascocoryne sarcoides, after all. I don’t think there’s much more to add at this point beyond a Merry Christmas and Happy New Year to all who have read this far!
Woodland web updates : 19

Woodland web updates : 19

by The blog at woodlands.co.uk, 29 July, 2022, 2 comments

Shade and stress. Shade (low light intensity) causes plants to elongate, reach up to the light to ‘outgrow’ the competition.  Such ‘elongated plants’ are said to exhibit etiolation.  However, there is a point when this strategy is counterproductive.  The plant simply cannot outgrow its taller neighbours, it is wasting resources and becoming weaker.  So plants in deep shade do not generally use this strategy.  Deep shade is detected by the phytochrome pigment system and ‘relayed' onto the plant’s circadian clock, the internal ‘daily time piece’.  This internal clock has various components and particular genes, some of which have an additional role in suppressing stem elongation (that would normally occur when shaded). Welsh woodlands and insect pollinators. A recent study across many different sites in Wales has revealed the habitats favoured by pollinators such as bees, overflies and butterflies.  The research found twice as many insects in broad leaved woodlands as compared to grassland areas.  They also found that farmlands without hedgerows had significantly fewer insects.  Both hedgerows and woodlands include trees such as oak and maple, which offer varied niches for pollinators.  They provide food (leaves) for larval stages, pollen and nectar for adults, plus egg laying sites and shelter. In Wales, there are plentiful grassland areas (mainly due to farming) with woodland only contributing 15% of land cover.  However, the Welsh Government aims to plant 180,000 hectares of new woodland by 2050.  New woodland will not only contribute to tackling climate change (through carbon sequestration) but will also do much to promote insect biodiversity. Sludge as fertiliser Sewage sludge is commonly spread across farmland as a form of fertiliser (throughout Europe).  Sewage sludge is the residual, semi-solid material that is the ‘by-product’ of sewage treatment of industrial and / or domestic wastewater. Sometimes, referred to as biosolids. It is a sustainable / renewable source of nutrients and reduces material going to landfill or incineration. The use of sludge has attracted attention as it can contain: Breakdown products of various medical / pharmaceutical that have been excreted / eliminated from us and / or animals, such as hormones, antibiotics, various drugs Heavy metals such as lead, cadmium, arsenic  Industrial chemicals / breakdown products PCB’s, dioxin Now, research at Cardiff University has shown that micro plastics in sludge are a problem; these are plastic particles less than 5 mm in size. It estimates that between 31,000 and 42,000 tonnes of micro-plastics are applied to European soils each year.  They are a threat to wildlife as they are easily ingested and can carry / contain toxic chemicals and may pass along the food chain.  The UK was shown to potentially have the highest level of microplastics in its soils, followed by Spain, Portugal and Germany.  
June Fungi Focus – Ash Dieback, Spring Pins and other Discomycetes

June Fungi Focus – Ash Dieback, Spring Pins and other Discomycetes

by Jasper Sharp, 6 June, 2022, 0 comments

June is the month when I’ve tended to find the first primary evidence of Hymenoscyphus fraxineus, the ascomycetes fungus responsible for the dreaded Ash Dieback. By this I mean that the while the presence of the disease is manifest all year round in terms of the sight of dead or dying ash trees, this is the time when one can first see the tiny ascocarp fruiting bodies responsible for spreading the spores. Hunt around in the debris at the base of an afflicted tree, and one can find these miniscule cream-coloured goblet-shaped ascocarps on the blackened fallen petioles and rachises of the previous year’s growth; the stems and stalks that make up the recognisable ‘pinnate’ leaf form of this species, with the blackening itself symptomatic of the presence of this destructive pathogen. The timing is interesting in that, with ash one of the last trees in our wooded environments to come into leaf, these ascocarps first begin to appear at a time when all good healthy trees should be in full leaf, shooting their spores (more specifically ‘ascospores’) into the air where they infect their host, unimpeded by the early plants of the woodland understory such as anemones, arums and bluebells that have by now died back for another year. The infection becomes evident on the tree itself with the blackening and wilting of leaves and shoots from July to September (Chalara fraxinea was the name for this separate asexual stage, and hence, before the link to the H. fraxineus was discovered, the name Chalara Ash Dieback took hold). [caption id="attachment_38272" align="aligncenter" width="675"] The unwelcome site of Hymenoscyphus fraxineus ascocarps growing from blackened twigs beneath ash trees.[/caption] I covered Ash Dieback in some detail a few ago, but for this months Fungi Focus, I want to discuss a few small lookalike species – the term discomycetes is used to describe the cup-shaped ascomycetes – that shouldn’t be such cause for alarm. The ascomycetes can be a horrible group when it comes to identification, with at least double the amount of species worldwide than the other major phylum of fungi, the basidiomycetes, and a scant few of them baring common names. Going by visible features alone, it is difficult enough to pinpoint down to genus level, yet alone species, with close microscopic scrutiny necessary to go any further. A case in point is Hymenoscyphus albidus, whose ascocarps look identical to H. fraxineus to the naked eye: Both grow exclusively on ash and both have the same blackening effect on the fallen petioles on which they grow. It is for this reason that H. fraxineus has also gone under the synonym H. pseudoalbinus. The only difference between this native fungus and the invasive interloper believed to have arrived from Asia, aside from the fact that it doesn’t kill its host, is that H. albidus does not possess hook-like “Croziers” at the base of its asci (where the spores are produced) – something that can only be ascertained microscopically.  [caption id="attachment_38273" align="aligncenter" width="675"] The related and near identical looking Hymenoscyphus scutula, fruiting on a dead bramble stem.[/caption] I don’t wish to blind the reader with science here, but one take home point is that if you do find tiny nail-shaped ascocarps on blackened fraxineus (ash) debris, it doesn’t necessarily spell doom for your local ash population – it might well be this harmless indigenous species. Another thing to consider is that the Ash Dieback fungus might not only be laying waste to our native ash population, but also outcompeting H. albidus in the process, thus another species falls under threat, albeit a miniscule fungi that is not quite so cherished as our ash trees and indeed is barely noticed by most of us. How many people are scouring the UK to estimate the ratio of H. albidus to H. fraxineus at the moment? Probably less than a handful, if any, I’d say. There are 155 species in the Hymenoscyphus genus according to Wikipedia, but there are probably many many more. Even the dozen or so listed in Peter Thompson’s Ascomycetes in Colour (2013) and Læssøe and Petersen’s Fungi of Temperate Europe (2019) look so similar as to make the eyes water. Some can be identified by their host – they might grow on leaves of specific plants, dead stems of herbaceous plants, or nuts and acorns – although never with total certainty. For example, I found similar tiny cream ascocarps growing on a dead blackberry stem. They seemed to fit the description of Hymenoscyphus scutula. The spores matched too, but even then, I couldn’t be 100% sure.  [caption id="attachment_38274" align="aligncenter" width="675"] These yellow discomycetes growing on a chestnut husk are probable Hymenoscyphus serotinus, although one can never be certain without checking under the microscope[/caption] Some are slightly more notable in the colour department. The small yellow cups I found growing on a chestnut husk could have been H. seritonus, or maybe H. monticola, or maybe something different entirely. I wasn’t going to bash my brains out trying to get any further in such cases, and nor should you. This is very very advanced specialist stuff. (For the record, as well as looking at spore shapes and sizes, the serious “ascomycetologist” would look at features such as the lengths of the asci and the ‘paraphyses’, the sterile hair-like filaments also contained as support structures within the fruit bodies). Anyway, lets move on to simpler things, namely two species of discomycetes that look superficially rather similar to the Ash Dieback fungi but are much easier to distinguish. These are Spring Pins (Cudoniella clavus) and Oak Pins (Cudoniella acicularis). One difference that can be noted with these and the Hymenoscyphus species is that the hymenium, the upward facing fertile surface in which the asci are embedded and release their spores from, is convex than concave – more dome-shaped than cup-shaped, although sometimes flatter. The appearance of both of these are of little nails or pins, as spelled out in the ‘clavus’ (for ‘nail’) part of the Latin name for Spring Pins. [caption id="attachment_38275" align="aligncenter" width="675"] Spring Pins (Cudoniella clavus), can be found growing twigs and other deciduous litter in freshwater environments..[/caption] Spring Pins, as the name suggests, appear from April to July, and usually in great abundance. They are not limited to ash trees anyway, but are found on any deciduous litter and dead wood in wet habitats; the ones depicted here were growing on fallen twigs in a ditch, a typical environment as they often appear in clean still or flowing freshwater habitats.  They are creamy white to yellowish and average around 4mm in diameter, getting up to 8mm according to Thompson, so do appear significantly larger than H. fraxineus. They are longer stemmed too, on average, and have a slightly gelatinous although not quite translucent appearance. This combination of size, shape and habitat should make this relatively widespread fungus not too challenging to identify. [caption id="attachment_38276" align="aligncenter" width="675"] Long-stemmed, gelatinous, with dome-shaped caps and slightly larger in size, Spring Pins are easy to distinguish from Hymenoscyphus species.[/caption] Oak Pins are also common. These are much smaller, with the markedly dome-shaped caps just 1-4mm in diameter, the margins slightly in-rolled so that from above they look like tiny gilled mushrooms such as the smallest mycena species – although a look underneath with a hand lens will clear up any doubt. These are much whiter than the other species discussed thus far, although develop black and brownish spots as they age.  One notable aspect to Oak Pins is that if one looks really closely, one can see that they are slightly hairy, particularly on the stems. But their substrate, not to mention their sheer proliferation across it, should be the real clincher for ID purposes. They almost exclusively appear on very old well-rotted oak stumps, and later in the year too – from August throughout the winter into March, although with the British climate as unpredictable as it is, quite possibly outside of these months. [caption id="attachment_38277" align="aligncenter" width="675"] Oak Pins (Cudoniella acicularis), another common find; smaller, whiter, with slightly hairy stems and discolouring with age.[/caption] June is hardly considered the best time to be out looking for fungi. These examples should show that there is still plenty about during the early Summer months, but many species are very small, very obscure and often very difficult to identify. This post, I hope should go some way to rectifying this final problem for some of them.  And if you do find what you suspect to be Hymenoscyphus fraxineus, don’t forget to report it. Happy hunting! [caption id="attachment_38278" align="aligncenter" width="675"] A proliferation of Oak Pins across a rotting stump.[/caption]

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