The other day I found a caterpillar of a campion moth (Hadena rivularis) nestling comfortably in the opened seed pod of, guess what, a red campion (Silene dioica).
I kept if for a day or two so that I could get a photo of it stretched out.
After our studio session had finished I gathered some fresh campion leaves and pods and the caterpillar immediately 'got its head down' as they say (see below). It is now, of course, too big to fit completely into the pods as it did when I first found it.
Moths seem to be even scarcer this year than before. In a wonderful, still, heatwave dusk I walked round the garden and saw no moths at all. It is now rare to find them on our windows after dark whereas 30 or 40 years ago one could expect to see a great variety of species here.
As well as moths, many other insects seem to be down in number. Our first hogweeds are out, but are hardly jostling with species as they used to be and honey bees are very few, though the recently arrived in Britain Bombus hypnorum, the tree bee, has had a good season and must have done much of the pollinating that is usually the province of the honey bee.
One of the few moths I have seen round the house is the small dusty wave (Idaea seriata), kindly identified by one of the experts on iSpot.
While yesterday a spotted a micro under a leaf (difficult to photograph) that turned out to be the Oecophorid Esperia oliviella.
Often caterpillars seem easier to find than adults. On the corner by the lane there is a hogweed almost completely eaten to pieces by larvae of the parsnip moth (Depressaria pastinacella). They seem almost to have created their own problems by being too many for the food supply.
Moths may be doing poorly, but butterflies seem to be managing quite well. Meadow browns are abundant and I have seen virtually all the species I would have expected to see by this time of the year.
For the last week or two our local hedgerows have been at their best. With, in places, masses of wild roses, honeysuckle and elder much now giving way to bramble flowers.
Summer flowers and grasses flourish along the hedge bottoms. One of the most characteristic grasses is false oat-grass (Arrhenatherum elatius) with its elegantly arching silvery flowering spikes.
Another silver surprise was a blackthorn (below) with silver leaves rather than the normal green as on the right of the picture. This is, I believe, a condition known as 'false silver-leaf'. Leaves also turn silver if the shrub is attacked by a fungus Chondrostereum purpureum but this kills the plant or the affected branches and this particular blackthorn seems perfectly healthy (although the false silver-leaf is caused by one kind of stress of another).
Hedge woundwort also seems to be doing well this year.
Anne Pratt (1852) remarks on the wooly properties of the plant and adds "one species of wild bee, which dwells in the cavities of trees, is skilled in using it. Kirby and Spence remark of this little creature, that it knew what materials would slowly conduct heat, long before Count Rumford's experiments had been made; and it attacks the leaves of Wooly Woundwort (Stachys lanata), the Rose Campion and similar plants, and scraping hence the down with its forelegs, rolls it into a little ball, and sticking it on the plaister which covers the cells, renders them impervious to every change of temperature; so that, say these writers, 'this bee may be said to exercise the trade of a clothier.' "
The bee in question is the wool carder-bee (Anthidium manicatum) and is particularly common in our garden where it shows a strong liking for flowers of houseleeks (Sempervivum spp.)
With us it mainly uses Stachys lanata to make its wool balls (see below).
The Count Rumford mentioned by Anne Pratt was the 18th/19th C Anglo-American polymath born Benjamin Thompson. Among innumerable other things he investigated the insulating properties of various materials including fur, wool and feathers. Kirby and Spence were authors of the Introduction to Entomology published in 4 volumes between 1815 and 1826.
Another insect that is a welcome visitor to our hedges this year is the small tortoiseshell butterfly (Aglais urticae). It used to be one of the commonest species when I was young, but now seems to be rather rarely seen, though it may have been picking up a little recently. I hope it isn't its relative scarcity that causes me to appreciate what a beautiful species it is.
Yesterday night I spotted a glowworm doing its stuff on the lawn in our garden.
I told my wife and she said "Oh do go and take a photo of it". So I did, and here it is:
On my way home I noticed, in the woodland edge, a beautiful red filigree of herb robert (Geranium robertianum) leaves. The plant had, I supposed, finished its flowering and was turning colour as a final flourish as the seeds set.
Back home I scrutinised the picture and discovered; not counting the grass and the dead oak leaf; field maple, ivy, hornbeam, bramble, yew, field rose, cherry laurel (an invasive alien) and hazel plus a couple of plants of whose identity I am uncertain, all sharing the moment. A good example of how nature is both dynamic and intricate.
Along the same path the wood melick grass (Melica uniflora) has already gone to seed.
It is regarded as an ancient woodland indicator plant, though I always find it on the banks on the edges of the woods and, although it looks as though (like floating sweet grass) it might have harvestable seeds, I can find no evidence of any such use. In the 1799 Letters and Papers on Agriculture, Planting &c, it is called 'wood honey-grass' and the anonymous author says of it This grass has beauty, and that only, to recommend it, unless to linnets, which are fond of the seed, which ripens in good time for them, being a very early grass. It was said to occur at Prior Park, presumably the one near Bath designed by Alexander Pope and Capability Brown and probably still does since it is a common enough grass.
The linnet is one of the many birds that have declined alarmingly in recent times and they do need a good supply of seed year round so, as an early seeder, one can see how wood melick would have been sought by them.
Although we have not had much of a summer, the pond in Killingan Wood is already reduced to mud and remains a good, fish-free habitat for some of the wildlife that prefers temporary water bodies.
There has been much in the media recently on the decline of honey bees and the lack of insects generally in Britain.
This does seem borne out by my own experiences. I have yet to see a honey bee in 2013, despite looking for them but two species of bumble bee have been doing well in our East Sussex garden
We have a nest of the tree bee, Bombus hypnorum, in the wall at the back of our house. The plant that seems to exert a powerful attraction for them is the alder buck thorn, Frangula alnus, although it has tiny greenish, scentless flowers.
The whole of our bush trembles with them, but they do not seem very interested in larger, more colourful flowers.
The tree bee is a relatively new species in Britain. Having first been recorded in Wiltshire in 2001, it has now spread far and wide and seems quite untroubled by whatever it is that is bothering the honey been and many other insects.
A self-sown and small flowered cotoneaster is another plant they like and on this they are joined in smaller numbers by the early bumble bee, Bombus pratorum.
In the wider countryside there are some lovely flowering meadows like Jackson Pollock paintings.
They do have insects in them, but not nearly so many as one would expect given the quantity of flowering plants. In this afternoon's warmth I was looking at a patch of white clover, Trifolium repens, a flower normally very attractive to bees and other insects, but there was no sign of any visitors.
Butterflies generally are scarce, but I have seen most of the species I would expect to see during the year so far, albeit in much lower numbers than usual. Meadow browns, Maniola jurtina, have just appeared and are usually common by now, but I only saw two this afternoon while walking through what appeared to be an ideal meadowland habitat.
Today and tomorrow are scheduled for a national British event called the Garden BioBlitz organised by a mixture of volunteer wildlife experts and enthusiasts with help from all over the place. See:
http://www.naturewatched.org/gbb.html#sthash.SepAezyI.dpbs
I spent a few hours revisiting the wildlife in the top half of our garden (so as to keep all records within the TQ782188 grid square) and submitted almost 150 records, something that rather understates the biodiversity of our home plot.
I took various photographs on my rounds and I think this first one sums up how rich a garden can be.
Elsewhere I saw a red-headed cardinal beetle (the 'sun' is a buttercup), here just about to launch into flight.
In my small Native Sussex Fernery outside our kitchen window the fronds of the royal fern, Osmunda regalis, are climbing rapidly. The taller ones rather remind me of Henry Moore's famous sculptures of Three Standing Figures.
These shoots are edible and were/are an ingredient in namul a dish of steamed vegetables used in the cuisine of the Korean royal court. In Japan they are called zenmai. In the interests of gastronomy I boiled a stalk with head for 5 minutes in water with bicarbonate of soda (it turned the water pale mauve), then rinsed it and ate it. It was very bland with a faint nutty taste, but not unpleasant. A good vehicle for oriental seasonings maybe.
As the picture shows they are a distinctive purple colour. The name 'royal' is said to derive from the imposing size of the fern when fully mature, though mine are not that impressive, so I wonder if the name comes from the colour of these young stems. Purple has long been associated with royalty. On the other hand, as my plant came from a local nursery stall, it may be that I have the form 'purpurescens', though the leaves when expanded are plain green.
In the late morning sunshine a female brimstone (I like to think of it as the female brimstone) came hopping back over the hedge to lay more eggs on our buckthorn bush.
After a while she settled on the ground for a rest, tilting over on one side so that she was not very obvious despite her colour.
Later she returned to egg laying in the buckthorn bush until chased away by an irritable-looking blue tit.
This little flowering plant, so often described as a weed, is currently brightening the ground by the north east corner of our house.
On close inspection the flowers are quite intricate and look like some alien babies with furry hoods and butterfly skirts flying above the maroon-flushed leaves.
Apparently a decoction from the roots was used in County Meath, Ireland "to bring out the rash in measles", something that I thought happened in the normal course of events. Despite the current measles epidemic, I hope people aren't rushing for the red-dead nettle roots.
Even more remarkable is a comment in Medicinal Plants in Folk Tradition (Allen & Hatfield, 2004) which I feel needs no further comment: "An infusion of Lamium purpureum, in a quart of wine, has been drunk in Essex as a treatment for piles."
In a wild part of St Leonards on Sea (sic), I found a dense belt of blackthorn with a post and rail fence running through. For reasons that were not entirely clear, the branches on one side of the fence were festooned with lichens among the flower buds, while those on the other side had none, not even the smallest amount.
I think the phenomenon may have had something to do with the age of the bushes, though there did not appear to be that much difference.
In the garden this afternoon, a female brimstone butterfly located our coppiced alder buckthorn bush and I watched her as she spent several minutes seeking out the twigs she favoured and laying a solitary egg just on or under a leaf bud.
This is the only alder buckthorn I know of within a radius of at least a mile (though I may have overlooked some) and I will always marvel at the unerring ability the females have in finding the plants.
Although it is still very cold, with a biting wind from the east, the sun shone for most of the day and in the garden at long last it felt more like spring than winter.
We have primroses and daffodils out but a very welcome newcomer was a daisy on the lawn opening its petals wide to the sunshine
As Shelley said in his poem The Question:
I dream'd that, as I wander'd by the way,
Bare Winter suddenly was changed to Spring
And later:
Daisies, those pearl'd Arcturi of the earth,
The constellated flower that never sets
'Arcturi' refers to stars, presumably in the region of Arcturus. The reference to it never setting means, I think, that daisies are nearly always in flower not that the petals do not close up at night.
Chaucer was also a great fan of daisies:
But I am up and walking in the mead
To see this flower against the sunshine spread.
When it upriseth early by the morrow :
That blissful sight doth soften all my sorrow
As well as daisies there were one or two insects about including this fly on our back wall. Not sure of the identity, but possibly an Egle species, an Anthomiid associated with sallow blossom.
After the very wet autumn and early winter we entered a period of cold, dull weather, punctuated by rain and snow that seemed to go on forever and ever. As I write on Maundy Thursday the temperature has not exceeded 15⁰C since 24 October last year and there have only been 30 days rising to between 10 ⁰C and 15 ⁰ C. At night lowest temperatures seem to hover between -2⁰C and +2⁰C. There was heavy, drifting snow between 11 and 14 March and snow flurries on many days including today.
The problem is a huge anticyclone that delivers modest to strong winds from the east so that the wind-chill factor makes it seem much colder than the thermometer reading. Tonight a low of -1 ⁰C is forecast but the wind-chill will take it down to -4 ⁰C. According to the forecast the whole of April is likely to remain cold. The warmer, Atlantic weather lies to the south and, so the meteorologists say, the jet stream would normally have moved up to the north of Britain by this time of year allowing the milder westerly winds to move in. This may be a natural variation or something to do with the climate change phenomena of a warming ocean or more ice-free water in the Arctic.
The countryside is variously affected. Spring flowers are coming out slowly and primroses are doing quite well, hazel catkins have struggled through and wood anemones are starting, but I have not seen any sallow blossom. The cherry-plums, Prunus cerasifera, are blooming well around Hurst Lane with their delicate white flowers coming maybe a week or so later than normal. However, the grass in the fields is not growing and insects are virtually absent which will be bad news for birds, some of which have already died of cold and hunger and must be particularly stressed if they have started nesting. An absence of early spring moths could mean a dearth of caterpillars just when the young birds need them and I wonder what might be happening to migrant species heading north from Africa. At least, on 5 March when the temperature topped 13 ⁰ C, I saw a fine male brimstone butterfly enjoying the sunshine at the corner of our local Churchland Lane and Killingan Wood.
Farming and gardening are also affected and, apart from poor sowing and growing conditions, there is no pleasure in pottering around the home plot. If I go outside, by the time I have written down the temperature, fed the birds and had a quick look at the houseleeks and other potted plants, it is time to head indoors. And, of course, it is not just Britain that is suffering. Much of Europe has been seriously affected and I have read that Russia is experiencing its coldest winter since 1938, the year I was born.
The seemingly endless cold, grey and windy weather is quite depressing and, with rising energy prices, expensive. We are currently using between £6 and £9 per day on electricity heating just one room and have a log fire most evenings, but even indoors I still have to have five or six layers of clothing on my upper body and thermal long johns and fur lined boots to keep warm.
The media tell us about records being broken and, apparently, it is the coldest winter since 1962/63 but the worst aspect is that it seems to go on and on in an unvarying way as though it is completely stuck with no intervening periods of warmth and sunshine as harbingers of better times. Very cold winters in the past have, in my experience, differed from this one with some nights of extreme cold bringing averages down. We have had nothing like the low temperatures down to -20 ⁰C that I have recorded here or at Robertsbridge in the past.
I fear the cold is taking its toll of some of our wildlife.
This afternoon I found this small, huddled corpse of a hedge sparrow in the log pile on the back wall of our house. It must have crept in among the wood overnight, but the frost was just too much for it especially as it might have been weakened by hunger.
Tomorrow morning it will be gone: a tasty snack for a fox or badger.
Since 11th March we have had arctic weather, with snow, frost and fierce winds from the east and north. Today it is melting quite quickly, though it is far from warm, making the drifts show up along the hedges and picking out shallow furrows across the fields with green parallels.
The animals and birds, some of which have already started nesting, are having a hard time and one of our garden wild rabbits climbed into a bush to browse on the rather unappetising looking shoots of a Coprosma from New Zealand.
The squirrels seemed relatively untroubled and carried on scampering about and twitching their snow sprinkled tails.
This afternoon in Churchland Wood, Sedlescombe, I found a fallen sweet chestnut (Castanea sativa) leaf spotted all over with pale patches bearing the fruiting bodies of a microfungus, easily identifiable as Mycosphaerella punctiformis.
This is what is known as a 'plurivorous' species that is also found on leaves of oaks, beeches and other trees. It has been recorded from several places in West Sussex, but this may be the first formal record from East Sussex (which only goes to show there is much recording work to be done on the lower plants).
Like the ash dieback fungus it is described by Wikipedia as a a pathogen. It is probably found wherever suitable leaves occur in our part of the world and, with many other microfungi, is important in breaking down and returning fallen leaves to the soil, so of great benefit rather than harm.
The number of spores dispersed by this and the myriad other micro and macro fungi is, of course, astronomical and the proportion of ash dieback spores in this ever present cloud must be vanishingly small.
The recent falls of snow covering our garden have not deterred Master Mole and he is sending up dark volcanoes of earth everywhere in order to create talpic impressions of spiral nebulae (TISNs).
The map below shows some of the main places mentioned in this note. Chalara fraxinea now occurs in all the countries shown, often quite widely. Places in red are of particular significance in the spread of this fungal pathogen around the coast of the Baltic Sea, the North Sea and the English Channel as discussed in the text below.
Chalara fraxinea and its teleomorph Hymenoscyphus pseudoalbidus, both stages of the fungus that causes ash dieback disease, have now been recorded from most countries in northern and western Europe, from Norway to Italy and from Ireland to Russia. It was first noticed in Poland and Lithuania in the early 1990s, although one account says it was first recorded in Latvia (Flora Locale, 2012), and has spread, and continues to spread, rapidly in all directions.
According to Kraj, W., Zarek, M. & Kowalski, T. (2012) there are several strains of C. fraxinea in Poland: “strains in lowlands were characterised by smaller number of markers, smaller number of polymorphic loci and smaller intrapopulation genetic variability.” Most of the populations considered in that paper are in hilly or mountainous southern Poland, whereas the different lowland strain occurred in areas close to the Baltic Sea to the west of the port of Gdansk.
As has been widely reported, ash dieback is now established in Lithuania, Latvia, Estonia, Baltic Russia (Kaliningrad), Finland, Sweden, Denmark and Germany, as well as Poland and these are all countries with a Baltic shore. The fungus is also now widespread in southern Norway, just outside the Baltic.
In the south the disease has advanced steadily across central Europe as far as France, Italy, Romania and other countries.
By following the history of these advances it appears that there is a maritime dispersal route and an overland dispersal route for this fungus. The terrestrial route seems consistent with propagation mainly by airborne spores of the H. pseudoalbidus stage and maps produced in France illustrate this well. In following the advance of C. fraxinea, it is important to try and discover the first reports in different areas as (a) the fungus spreads very rapidly and (b) once discovered far more people start looking for it. Also it has to be borne in mind that it may have been present for some years before being detected. Because of this and other factors, possible dispersal routes become unclear quickly.
The maritime dispersal route seems more complex than the overland and, while wind borne spores are likely to play a major part in the overland dispersal routes, there would seem to be some other vector involved such as bird migration or shipping on the maritime routes.
The disease has, for example, been a problem on several Baltic islands. In Öland and Gotland (both Sweden) ash trees have been ‘ravaged’ by the disease, while in Finland it was first discovered in the Åland archipelago in 2007 some 170 km (100 miles) across the Baltic north from the nearest area known to be infected at a time when it had not been reported from the Finnish mainland (EPPO, 2007). Much shipping passes close to these various islands en route to places like Stockholm, Helsinki and St. Petersburg and, of course, they all have cruise liners calling and ferry services to the mainland.
In Germany C. fraxinea was initially widespread in the north of the country (Schumacher, GALK) near the Baltic rather than in the south, while in Denmark it was first recorded in 2002 near Haderslev, a small port on the Baltic side of the Jutland peninsula. The following year it was found in Zealand and Bornholm, the latter a Danish island to the east of the main part of Denmark and well out in the Baltic Sea. Haderslev is the home of a company called Euro-Timber that trades widely in timber products throughout the region, though this, of course, may have nothing to do with the spread of C. fraxinea. There is also a frequent ferry service from Swinoujscie in northern Poland to Bornholm island and Ystad in Skåne (Scania), southern Sweden, where ash dieback has ‘raged’.
The disease was first found in Norway in a nursery in the Østfold region in the most southerly part of the country in 2007. There is a frequent ferry service from Hirtshals in northern Jutland, Denmark, to Kristiansand the capital of Østfold and, of course, much shipping passing through the Skagerrak from the Baltic to the North Sea.
Ash dieback was first reported from The Netherlands in 2010 (later than in many countries) in young trees in public parks in Bellingwedde in the far north east of the country close to the German border and about 15 km south of the coast at the Dollard (German: Dollart) an inlet from the Wattenmeer, part of the North Sea lying between the Frisian Islands and the coasts of The Netherlands, Germany and Denmark. The busy German port of Emden lies on the northern side of The Dollart 25 km or so north of Bellingwedde.
The first report of ash dieback in Britain was from a nursery in Buckinghamshire in 2012 on trees from The Netherlands that were said to be infected. This may be demonstrably true, but increasingly suggestions are being made that the pathogen has been present in Britain and elsewhere since well before its first report and, if this is correct, at least some nursery stock may have been infected from local woodlands after importation. The disease has spread quickly through The Netherlands and, although the Dutch phytosanitary authorities suspect that it was present before the discovery in Bellingwedde, it does seem to have made its initial entry close to the coast in the north of the country. The distance from there to East Anglia is not as great as some of the distances that C. fraxinea seems to have travelled over the Baltic Sea and this indicates that airborne spores might survive quite long and cold journeys, though if wind or birds are important as vectors it is difficult to explain why the disease seems to have jumped over intervening territory on the nearby mainland.
In Belgium the first report was from Silly in the province of Hainaut in 2010. This is some 75 km from the port of Antwerp and 91 km from the Belgian coast at Bruges thus its route into the country may have been overland from the east rather than via the North Sea fringe (the disease is established both in northern France, southern Germany and Luxembourg). The Belgians were sufficiently worried about the spread of the disease to undertake extensive testing of ash trees for C. fraxinea in 2009 in the province of Wallonia (Delhaye, Helson, & Chandelier, 2010). No infection was found, but when the experiment was repeated in 2010, the fungus was present at several sites – a good illustration of the speed at which it can spread.
The situation in France presents some interesting data. The spread of ash dieback has been closely mapped by, among others, DRAAF (Direction Régionale de l'Alimentation, de l’Agriculture et de la Forêt). In an information sheet published in June 2011 (DRAAF, 2011) they showed that the disease was widespread in north eastern France in 2010 but there was only one dot on the map in the Pas-de-Calais over 300 kilometres (186 miles) from the next nearest French site, though probably slightly closer to some of the Belgian sites. In the north east the disease spread south and west in 2012, while it was also detected in an increasingly large area around the Pas-de-Calais site in 2012.
However, it also turned up in 2012 as an apparently isolated occurrence 265 km (165 miles) south west of the next nearest French site on the coast of the Cotentin peninsula in the department of Manche in Normandy (Association des Communes Forestières de la Côte d’Or, 2012). This map also shows how C. fraxinea advances relatively short distances overland and along a specific front.
The French coast on this part of the Cotentin is only some 28 kilometres (17 miles) from Jersey from where ash dieback was reported in November 2012. According to the Jersey Evening Post “The infected ash tree has been identified as one of a number imported into the Island from the UK in 2010 or 2011.” If this is correct, it is just as likely that the fungus was brought in from the UK as having established itself by windblown spores from Normandy. Indeed, the Normandy outbreak may have come from Jersey or Guernsey where the disease has also been found. Again, if the trees were infected before they left for Jersey, the disease must have been in mainland Britain before February 2012, the date that is often given for its arrival. It does no injury to logic to suggest that the outbreak in the Pas-de-Calais might have come from Britain, especially as the Forestry Commission are now suggesting that the disease has been in East Kent for some time.
While movement of plants undoubtedly exacerbates the problem of introducing pathogens to areas where they have not been previously recorded, there is a tendency to blame other countries for exporting infected stock. As one senior French forester said when asked how he thought C. fraxinea had arrived in north eastern France: “On suppose l’importation de plants contaminés.”
So far as the British Isles is concerned, virtually all the current records of Chalara from the wider environment (i.e. not from nurseries or recent plantings) are on the eastern side of the country, many close to the coast. While wind borne spores from mainland Europe may be responsible for many of these outbreaks, most are also near ports, places where there are many arrivals and departures of people and goods to and from other countries. This is particularly apparent in the area around Dover and Folkestone (Forestry Commission, 2012).
In sum, the forms of Chalara fraxinea that have travelled overland from Poland, and maybe other parts of eastern Europe, generally seem to have advanced a relatively short distance each year that is consistent with establishment by wind borne spores, whereas the near-the-coast occurrences often seem to have made long hops apparently without settling on places in between. This could mean that there is a vector for C. fraxinea and some other plant diseases apart from the wind, birds and other fauna, and imports of infected material. It seems possible that shipping, and particularly cruise ships ferry services, may be the carriers of spores even when there is no mature infected material from the host plants on board. The environment on these vessels may help spores to retain viability in some way. This could also explain why Chalara fraxinea seems to have an affinity with islands, rapidly spreading to Bornholm, Öland, Gotland and the Åland archipelago in the Baltic, as well as the British Crown Dependencies of Jersey and Guernsey all of which are dependent on ferries and welcome cruises and other shipping services.
Also the isolated 'wider environment' outbreak in the Buckie area of Scotland shown on the Forestry Commission's map of 11 December 2012 might be due to shipping "Buckie Shipyard offers a wide ranging capability to the marine industry , including new build, conversion, refit and repair of ferries, tugs, workboats, yachts, pilot boats, MOD vessels, small cruise vessels, diving vessels, lifeboats, fishing boats and fish farm cages."
There is a growing view that Chalara fraxinea originally came from the Far East and there are, of course, shipping services, from there to the Baltic. The Fesco Baltorient Line, for example, runs cargo vessels from the Far East to St. Petersburg and other European destinations.
Another curious aspect of the disease is that the map of Britain produced by the Forestry Commission shows sites where the infection has been confirmed in recently planted sites (including ? nurseries) scattered very widely from Cornwall to northern Scotland and in Wales and Northern Ireland. In France, however, most of the country seems to remain untouched, though the disease is advancing southwards on a broad front with hardly any egregious records. In other words it appears to be widespread in British newly planted sites but not in French.
Oliver Rackham (2012) also seemed to think, having considered the options, that there was something about the expansion of Chalara fraxinea that we did not quite understand: “Many reported outbreaks, in various countries, are linked to the nursery trade, both within and between countries. Ash seedlings grown in nursery conditions are evidently very susceptible to infection, and can convey it long distances or to islands that it might not otherwise reach. However, occurrences like that in Ashwellthorpe Lower Wood, not obviously linked to any nursery, show that this is not the only explanation. Ascospores blowing from the Continent are a possibility — they are small enough to get that far. However it seems unlikely that a single spore, after a wind journey of hundreds of miles, would have enough inoculum potential (as Dennis Garrett, the great plant pathologist, taught me in the 1960s) to start an infection, though maybe a mass of conidia on the foot of a bird might do so on rare occasions.”
REFERENCES
Association des Communes Forestières de la Côte d’Or (2012), http://cofor21.over-blog.com/article-la-chalarose-108098766.html
Delhaye, N., Helson, M., Chandelier, A. (2010) La chalarose du frêne : premiers foyers en Wallonie. http://www.foretwallonne.be/images/stories/pdffolder/fw108_49-56[chalarose].pdf
DRAAF (2011) Forte progression géographique et des dégâts de la chalarose du frêne dans le Nord de la France http://draaf.nord-pas-de-calais.agriculture.gouv.fr/IMG/pdf/info_tech_61_chalarose_cle088e84-1.pdf
EPPO (2007) Ash dieback in Europe and possible implication of Chalara fraxinea: addition to the EPPO Alert List. EPPO Global Database Num. Article: 2007/179 Year: 2007 Month 09. http://gd3.eppo.int/reporting.php/article1225
Flora Locale (2012) Ash dieback, tree planting and the plant trade. http://www.floralocale.org/ash+news
Forestry Commission (11 December 2012) Chalara fraxinea Map 2b. Confirmed infection sites http://www.forestry.gov.uk/pdf/UK_outbreak_map-12-12-11_Map2b.pdf/$FILE/UK_outbreak_map-12-12-11_Map2b.pdf
GALK.de (n.d.) Editorial on ash dieback http://www.galk.de/projekte/akstb_krankheiten.htm
Kraj, W., Zarek, M. & Kowalski, T. (2012) Genetic variability of Chalara fraxinea, dieback cause of European ash (Fraxinus excelsior L.). Mycological Progress, February 2012, Volume 11 (1): 37-45 http://link.springer.com/article/10.1007%2Fs11557-010-0724-z?LI=true
Rackham, O. (2012) Ash Disease: the present state of knowledge or ignorance. 9 November 2012.
Schumacher, J. (2010) Essterfte door Chalara fraxinea.
http://www.boomadviseur.nl/nieuws/40/essterfte-door-chalara-fraxinea
I continue to follow, albeit rather wearily, the ash dieback debate through many authors in newspapers, magazines and blogs, both here and in other countries.
There now seems to be a general consensus that infection is by wind borne spores and there is little that can be done to stop the progress of the disease. It is thought like that up to 10% of ash trees will be resistant to the disease and that these may be an important resource in ensuring the ash's future recovery.
There has also been much debate about the pros and cons of large tree planting schemes and it is frequently pointed out that Britain has proportionately less woodland cover than almost anywhere else in Europe.
This has brought the issue of natural regeneration rather than deliberate planting to the fore. In East Sussex where I live I know of many places, usually abandoned fields, that have regenerated to secondary woodland surprisingly quickly and, judging by the size of the saplings I have seen in some televised tree planting schemes (maybe only from seed this year), regeneration may be almost as fast, if not faster than planting. Though it does not do much for the tree nursery trade, or other human engagement with tree planting schemes.
I think the regeneration point is well-illustrated by this from Julian Roughton as a comment on a Guardian article: In 2005 Suffolk Wildlife Trust bought a 40 acre field alongside an ancient woodland reserve - no trees were planted to see what would naturally emerge. Now there are something like half a million young ash trees many ten feet tall as well as birch, oak, field maple, hawthorn and blackthorn. Despite no tree planting thousands of young ash saplings are now affected by ash die back. Hopefully some of those half a million young ash trees will emerge with some resistance but where they die other tree seedlings are likely to take hold.
There also seems to be a conflation of trees with woodland. We cannot have woodland without trees, of course, but woodland is much much more than just trees. Not only does it have important open spaces like glades and rides, it has something known as an edge ranging from almost bare ground through shorter grasses and herbs to scrub and various shrubs unlikely to survive in closed canopy conditions. This woodland edge often contains the greatest biodiversity and is much loved by species like nightingales, dormice and pearl-bordered fritillaries, all species often associated with woodland but preferring scrub and more open areas. There are also many species that spend part of their life within the tree canopy and part in the sheltered sunshine of the woodland edge.
The chair of The Woodland Trust, Clive Anderson, pointed out is an Observer article yesterday that with natural regeneration "It can take a while for trees to force their way through grasses, low-growing plants and scrub, but they will get there in the end." True maybe, though self-sown trees, as I said above, can grow very quickly. However, grasses, low-growing plants and scrub are just as much part of the natural environment, and just as important to wildlife as woodlands.
As has often been remarked, nature is dynamic and is constantly undergoing change and alteration. Woodland may be termed climax vegetation but trees eventually die and the space is created which is the other side of the forest coin. I have long thought that we are failing to appreciate the diversity and complexity of wildlife if we compartmentalise the landscape too much: that is a wood, that is a heath, that is a field. Until recently housing or commercial developments were allowed to go right up to the edge of an ancient woodland, but now a buffer of 30 metres or more is often specified. This buffer is to provide a wonderful mixed edge of "grasses, low-growing plants and scrub" on which the life of the wood is partly dependent.
It would be silly to suggest that all tree planting schemes should stop, but it would be nice to see more natural regeneration schemes such as that by the Suffolk Wildlife Trust mentioned above being promoted, studied and discussed. If a field were to become available for tree planting, for example, one half could be reserved for natural regeneration.
Two famous examples of this are the Geescroft and Broadbalk wildernesses at the Rothamsted Experimental Station in Hertfordshire. Here arable fields were abandoned in the 1880s and have long been regenerated woodlands. There is an interesting comment about this in Footprints in the Soil (2006) edited by Benno Warkentin: These two historic Rothamsted sites illustrate the very considerable potential for carbon sequestration of simply allowing the steady state vegetation to re-establish itself. Actively afforesting arable land will obviously be effective, but the more the soil is perturbed, the longer the benefit will take to materialize."
This weekend I was watching a tree planting day in Leicestershire on TV. The small saplings were being planted in what was obviously stubble from a recent grain crop. I did wonder, in these days of grain shortages, about the pros and cons of turning arable fields into woods. And I also wondered about the transactional details of the arrangement. There was no discussion of this on the TV programme. Via some quick research I found out that arable land in Leicestershire is on offer at around £9,000 per acre ... I assume a farmer would not want to arrange for extensive tree planting on arable sites unless there was some sort of financial return far beyond the scope of the kinds of grants offered by the government for farm management with wildlife in mind.
One final point, while many pests and diseases have been transported from their natural homes to somewhere else, I suspect that pathogens like ash dieback are often a natural phenomenon and that many plant species have gone through the kind of reversal now afflicting ash trees. It just underlines that our human perspectives are often little longer than the average lifetime.
From this time of year we always have two or three woodpigeons (Columba palumbus) eating the ivy berries on top of the hedge and in the tree behind.
Ivy berries contain toxins, but many birds seem able to cope with them. Pigeons, however, eat the rather soft seed where the toxins are said to be concentrated, as well as the fruit pulp and can destroy over 75% of the ivy seed crop. They start with the unripe berries at this time of year and continue to feed on them right through to spring when they are properly ripe.
A small mid-November treat today was the appearance of the beautiful plume moth (Amblyptilia acanthodactyla) on the wall by our back door. This second generation emerges in autumn and goes into hibernation until spring, but this one quite evidently had not yet decided to settle down despite the fact that we have already had a couple of frosts.
The larvae feed on a variety of plants including hedge woundwort (Stachys sylvatica), of which we have a very large patch only a few metres from where I found the moth today.
The beautiful plume is one of those species that is increasing and these days is increasingly found in gardens, highlighting their value for some forms of wildlife.
Two very interesting articles have been published recently on ash dieback disease (Chalara fraxinea).
One, in the Telegraph, is by Cole Moreton who went to the forest area in Zabodny, Poland, where the disease was first noted in Europe in 1992:
It paints a very gloomy picture of the prospects for ash trees in the UK. One of their forest managers was asked about prospects here:
“Has it been seen in the older trees?” It has. This experienced man of the forests puts his hand on his heart. “Then I am afraid it is over for you. It is too late. The game is over.” However, the Poles pointed out that 15 to 20% of trees survive and seed from these might carry the immunity to future generations.
While this may seem to be a good thing, the warning from the Botanical Society of the British Isles (BSBI) should be heeded: "Woodland plantations and hedgerows made of cloned stock or non-native trees are going to be even more prone to failure than most food crops, as they are so long-lived." In other words it is important to maintain genetic diversity and not take all future ash trees from one or two genetically identical, or very similar, clones." The BSBI also say, rather more encouragingly: "Ash dieback, like other diseases of wild plants, is simply part of the ecosystem, and its main effect is likely to be to increase diversity and ultimately the stability of woods. Even if it were possible, there would be no point in trying to isolate British plants from worldwide diseases, because that would make them more vulnerable to serious plagues in future."
The whole article is here: http://www.bsbi.org.uk/ash_dieback.html
Their assertion though that "ash dieback is not known to kill mature trees" does not seem to be correct in the light of experience from Poland and elsewhere.
Another enlightening web site is TreeBASE (a database of phylogenetic knowledge) which almost certainly explains various reports that ash dieback came from Asia or China. In fact the fungus seems to be present in Japan on Manchurian ash (Fraxinus mandshurica) a species found in China, Korea and south east Russia as well as Japan. TreeBASE say: "Hymenoscyphus pseudoalbidus is the causal agent of ash (Fraxinus excelsior) dieback in Europe. It was recently separated from the European H. albidus based on molecular analyses, while morphologically scarcely distinguishable. Hymenoscyphus albidus was reported under the nomenclatural synonym Lambertella albida on petioles of Fraxinus mandshurica in Japan." It then gives some rather more complicated details.
http://www.treebase.org/treebase-web/search/study/summary.html?id=12500
On the assumption that the fungus was present in Japan before Europe, Manchurian ash may, of course, be rather more resistant to the disease than European ash, but much more work needs to be done to establish the evolutionary pathways and possible dispersion routes of spores of both the European and Far Eastern strains of Chalara fraxinea, although such knowledge may not enable anyone to stop its advance, it could help with mitigation strategies.
Work on Chalara fraxinea seems to have been done by scientists in Japan, Poland, Denmark, Belgium, Switzerland, UK and probably many other places. What I find rather disturbing is that they do not appear to be talking to one another and reading one another's papers. Or maybe they are simply being ignored.
Below: a healthy (for how long?) coppiced ash.
Many people in the media still seem to be behind the times on ash dieback and continue to prattle on about Denmark and how the disease is widespread in Central Europe (home of Count Dracula etc.)
Chalara fraxinea had spread to north west France by 2009 and Belgium since at least 2010. For more detail see: http://tinyurl.com/d6soy9s
The Forestry Commission map of Chalara outbreaks ignores the very significant fact that the disease is widespread in the bit of France shown bottom left just opposite the Kent outbreaks See: http://tinyurl.com/d4qp7t5
Surely it is pointless to 'take action' of whatever kind here when spores will keep arriving from Europe unless the disease declines of its own accord. I continue to read of hundreds of people scouring the countryside for infected trees, but it is not quite clear what they do when they find them. Do they destroy the whole thing, roots and all, and hoover the entire woodland floor or length of hedge for any spore carrying leaves?
Are these hundreds of people volunteers, long-term employees of someone, or recent recruits? Have they stopped doing their proper job? Whenever hundreds are involved there is usually a significant cost. Is it worth it?
Another piece of data that seems to have lain undiscovered is that ash dieback was added to the European and Mediterranean Plant Protection Organisation's (EPPO) alert list in 2007. They said: "Because ash dieback could represent a serious threat to forest, amenity and nursery ash trees, the EPPO Secretariat decided to add C. fraxinea to the EPPO Alert List in 2007." The UK has been a member of EPPO since 1951 but seemingly ignored this warning. See: http://tinyurl.com/catk78n
I think I am suffering with Roper dieback.
My mail box continues to be crowded with injunctions to help stop the spread of ash die back disease, Chalara fraxinea. As someone who has done many years of study on our native trees and has the greatest possible affection for them I do not want to be seen as not caring about the ash.
However, I do think we have to be realistic. It seems to me there is little chance of stopping a fungal disease that is spread by spores and is widespread all over Europe right up to the Channel coast from advancing into the UK (as the Forestry Commission suggest it already may have done) by perfectly natural means as well as on imported plants.
Prompted by this recent emergency I was particularly noticing ash trees on my way into Hastings this morning, a journey of about 10 miles. There must be thousands, many the young trees that appear to be particularly susceptible, in hedgerows, on embankments as well as in the edges of the woodlands that I could see. It would be very difficult to survey all these trees carefully for die back and, if the disease were found the prospect of the damage to the countryside that would result from unearthing them from hedges etc. is alarming.
Where the A21 enters Hastings there are steep embankments covered in young ashes on either side of a road bridge. If the disease were to occur here, trying to deal with it (bearing in mind that it might be in the roots as well as in the top hamper) would involve major engineering works and probably significant road closure.
It occurs to me that the disease has probably been identified in plant nurseries and on Forestry Commission and Woodland Trust properties because young trees in these places get much more detailed scrutiny than elsewhere. Many woods have thousands of young ashes as well as older ones, often in rarely visited spots and systematic survey and destruction of the infected would involve an impossible amount of people hours and cost. There will no doubt be extra vigilance in well-visited woods, but there are many places where ashes grow on farmland and other private property where detailed scrutiny is unlikely to take place. Indeed, one of the characteristic habitats of the ash is on vertical limestone and other cliffs ...
While the present government does not seem to be particularly pro-wildlife, blaming them for outbreaks of ash die back in the wild as a consequence of not preventing imports of the trees sooner than they did seems like blaming the American government for hurricane Sandy.
If ash die back becomes widespread in the UK, as seems likely based on the experience in other European countries, it might be better to look for trees that do not have it rather than those that do. As I said in yesterday's post, there seem to be some chalara-resistant strains of ash and these will need to be cherished.
Recently I have read and listened to many items about the fungal infection Chalara fraxinea or ash die back disease that kills the trees it attacks. While I am sure no one would welcome any serious threat to our native ash trees, it does seem to me that much of the commentary is ill-founded and not very helpful.
The general story from the media is that nearly all the ash trees in Denmark have died, that a few cases have been found in Great Britain and that imports of ashes from nurseries abroad have been banned.
A good way of getting a more balanced understanding of the situation is by reading the Forestry Commission's fact sheet on the issue:
http://www.forestry.gov.uk/chalara
According to the FC the disease was first recorded in Poland in 1992 (other sources say 1990) and infected trees have been found widely across Europe, including several places from Kent to central Scotland in the UK. Infected trees are widespread in north western France with up to 80% affected in some areas and the fungus has also been reported from Belgium where "eradication measures have sought unsuccessfully to stop the spread of the disease".
In a recent Guardian article George Monbiot said “The only way the fungus can arrive in this country is through imports of infected saplings.” However, as it is a fungus presumably it spreads by spores that can travel in all sorts of ways. Indeed, the FC in their fact sheet say that "It is believed to have entered Great Britain on plants for planting imported from nurseries in Continental Europe. However, now that we have found infected older trees in East Anglia with no apparent connection with nursery stock, we are also investigating the possibility that it might have entered Britain by natural means. These include being carried on the wind or on birds coming across the North Sea, or on items such as footwear, clothing or vehicles of people who had been in infected sites in Continental Europe." (I wonder how they are going to investigate these possibilities).
The banning of imports might, I suppose, slow the spread of the disease, but it looks rather like shutting the stable door after the horse has gone. If it can spread for some distance by spores from nursery stock it can, presumably, find its way across the Channel. Most of us remember how fast the horse chestnut leaf miner moth spread: stopping imports of its host would have made little difference.
So far as containment is concerned the FC say "We are treating C. fraxinea as a ‘quarantine’ plant pathogen, which means that we may use emergency powers to contain or eradicate it when it is found. This is being done in the form of Statutory Plant Health Notices which we serve on affected owners requiring them to remove and destroy affected plants by burning or deep burial on site. Equivalent measures are being taken on land managed by the Forestry Commission. This is the only available treatment."
If the same situation prevails here as in mainland Europe landowners are going to be faced with an impossible and probably worthless task. If infected trees were found, for example, not only the top but the roots would have to be burnt or deeply buried. And what about trees nearby that might be infected but not yet showing symptoms. Would the National Trust, for example, be expected to dig up and burn or bury all the ash trees in Dovedale should Chalara strike there?
Sadly I suspect the FC and other government advisers know perfectly well that they are unable to stop spores crossing the Channel and that the current red flag waving and whistle blowing is just to try and show a public that loves its trees that something is being done.
With Dutch elm disease, the various afflictions of oak, phytophthera on sweet chestnut and other species I sometime wonder if these diseases might be the way nature operates, killing whole swathes of trees from time to time and opening up forests for other flora and fauna. Often a few individuals of the species attacked seem to survive, like post-myxomatosis rabbits, to repopulate the old habitat which, by then, may be relatively free of their pests and diseases since these have had little or nothing on which to subsist. Indeed in a Danish study (which might have given rise to the frequently heard comment that Denmark is particularly badly affected by ash die back) it has been shown that different strains of ash have different levels of resistance.
Unless the disease mysteriously dies out naturally in nearby mainland Europe and where it has appeared in the UK, which seems unlikely, might it not be better to let things run their course? In good natural selection style, the fittest would survive and repopulate our countryside with resistant strains.
A mainly sunny day after the recent heavy rain and winds.
Halfway down our garden we have a bush of Colletia hystrix ( often listed as Colletia armata in catalogues) that produces masses of white, honey scented flowers at this time of year attractive to a wide range of insects, late butterflies being the most obvious.
Today here were literally dozens of visiting red admirals, Vanessa atalanta (above), maybe 30 or 40 of them, and I have never seen so many as this together. There were also a few commas, Polygonia c-album, and a couple of southern hawker dragonflies trying to pick off some of the smaller insects attracted to the flowers.
Colletia hystrix, a member of the Buckthorn Family, comes from Chile where it is known as espino negro (i.e. blackthorn) or yaqui. It is a very spiny plant and can be used, like gorse as a stock fence. Ours is now about 4 or 5 metres tall and makes an impenetrable, but attractive, thicket. It seems perfectly hardy in Sussex.
Went for a walk today at on the south east side of Woodchurch between Tenterden and Ashford in Kent. The only cross-country path suitable runs from Lower Road to the Appledore Road across the Weald Clay and partly on an area of alluvium.
However, there was a fine view back towards the village and the church (looking north north west from TQ949339).
The stubble is the remains of oil seed rape and the dark green along the footpath is made by thousands of young plants grown from fallen seed. In winter the pigeons will love it.
A friend who lives in the Bohemia Road area of Hastings phoned yesterday evening to say that I might not believe this but a yellow, black spotted snake had appeared in their kitchen sink.
They had covered the sink with a board, but lifted it long enough to take the photo above which they texted to me. After various phone calls and emails they managed to find a local vet with an interest in snakes to come and take the unexpected visitor to more congenial quarters. He also confirmed its identity as a king snake.
I think it is a hybrid between the desert king snake, Lampropeltis getula splendida, and the speckled king snake, Lampropeltis getula holbrooki. Various forms of these snakes are popular among reptile enthusiasts and www.thekingsnake.co.uk says "They have a relatively docile temperament and can be easily tamed. They are energetic and inquisitive and make very interesting pets. They are easy and safe to handle, growing to a manageable size and make a good choice for people who are new to snake keeping."
However, I doubt whether the Hastings climate is suitable for them to make a permanent home in the town outside captivity.
