Woodlands.co.uk https://www.woodlands.co.uk Woodland for Sale in the UK Sat, 18 Jan 2020 18:31:03 +0000 en-GB hourly 1 Climate change, forest fragmentation, fire and disease https://www.woodlands.co.uk/blog/flora-and-fauna/climate-change-forest-fragmentation-fire-and-disease/ https://www.woodlands.co.uk/blog/flora-and-fauna/climate-change-forest-fragmentation-fire-and-disease/#respond Fri, 17 Jan 2020 08:15:19 +0000 https://www.woodlands.co.uk/?p=32519

The Earth is warming as a result of the release of carbon dioxide from fossil fuels, leading to a period of rapid and significant climate change, which is seen as an existential threat to humanity by many. It is possible that the tipping point has been reached, where the effects of global warming, such as the loss of polar ice sheets, are unstoppable.  The most dire ‘predictions’ think that cities, industries, countries, and perhaps our species will be lost.

Climate change is not new and variations in the patterns of weather have provoked the collapse of regimes and cultures throughout recorded history. Social and economic constructs have unravelled and  populations have declined.

We know something about some of these past changes in weather and climate from various sources.  Dendrochronologists have used wooden artefacts and examined material from many different tree species to build up a picture of when the climate was favourable for tree growth (then the rings would be widely separated from one another), and when conditions were more difficult perhaps due to drought or cold.  Many of the studies on tree rings were undertaken by "Mike"Baillie (Professor Emeritus of Palaeoecology at Queen's University of Belfast). He was instrumental in constructing a chronology of tree-ring growth that extended back some seven thousand years.  He has proposed that climatic downturn seen in many parts of the world in circa 540 AD was due to an explosion of a meteor in the upper atmosphere*. This gave rise to an 'envelope' of dust and ice that surrounded the Earth, resulting in a drop in global temperature. This can be traced in tree ring samples across Europe, Siberia, North and South America and Scandinavia. The unseasonable weather gave rise to crop failures and famine.

Tree ring data from Mexico and other parts of North America indicate that there was a severe drought in the sixteenth century, and that this drought extended from Mexico to the boreal forest, from the Pacific to the Atlantic Coast.  The only areas exempt from the drought were coastal regions.  This extended drought coincided with two major epidemics (in 1545 & 1576) of cocoliztli.   This was a swift and lethal disease, with a high death rate.  ratIt seems to have been a form of haemorrhagic fever (as is Ebola), and was probably responsible for the deaths of millions of the native population of Mexico.  It has been suggested that the virus ‘jumped’ from rodents to humans. The rodent population had exploded when wet years followed prolonged periods of drought.  Again tree ring data support the idea that the drought was occasionally interrupted by wet years – as in 1545.

Other scientists have drilled down into the ice sheets of Greenland and Antarctica, and have extracted ‘cores’ of densely packed ice. The deepest ice in Antarctic cores might be hundreds of thousands of years old. By examining the ratios of oxygen and hydrogen isotopes in the different ice (compacted snow) layers, they are able to determine how patterns of precipitation have fluctuated around the poles.  This gives information about the Earth’s average annual temperature over the centuries. Plus, bubbles trapped in the cores contain minute samples of the ancient atmosphere. These, when analysed, reveal data about the concentration of carbon dioxide and other gases in the atmosphere.

An alternate source of information about past climates and weather events is oral or written records.  For example, the log books of ships (in the days of sail) can yield detailed information about wind and rain across the world's oceans.

By studying both qualitative and quantitative information from a variety of sources, it is clear that the Earth’s climate even in relatively recent times (the last 2000 years) has not been static.  For example, it is now clear that cooling extended across the Northern Hemisphere from the 13th century onwards.

The causes of the cooling have been attributed to

  • cyclical changes in the orientation of Earth’s rotational axis,
  • decline(s) in solar radiation,
  • fluctuations in oceanic and atmospheric currents, and volcanic eruptions

The “Little Ice Age” is a term sometimes applied to these periods of cooling, a number of which occurred at different places and times. Glaciers probably expanded but it was not an ice age in the true meaning of the term - where ice sheets covered vast areas of the globe. Even the coldest decades of this period probably did not see a cooling that exceeded an annual drop in temperature of more than 0.5o C.  Parts of northern Europe were subjected to years of long winters and short, wet summers, whereas in southern Europe droughts occurred but also long periods of heavy rainfall.  For those who lived through it, this was no trivial matter.  Malnutrition and famine were commonplace and there were outbreaks of plague which spread across parts of Asia and Europe, and were responsible for the death of millions. Some have suggested that ‘unstable / changing weather’ promoted oscillations in the rat populations; rats act as vectors for the fleas that spread the plague.

The environmental challenges we now face are far greater than those of the past.  Recently, we have witnessed outbreaks of the Ebola virus.   The virus can exist in animal populations, possibly such as bats, without affecting them.  It has been suggested that changing weather patterns (dry periods followed by heavy rain) have resulted in an abundance of fruit - which has attracted apes and bats to the ‘glut’ of food, providing opportunities for inter-specific transfer of the virus.
The change in climate may have also resulted in bats extending their range and therefore increasing contact with humans (directly or indirectly). We can contract the virus by eating or handling an infected animal.

The United States Agency for International Development has noted that many of the new, emerging, or re-emerging diseases are “zoonotic” — that is they originate in animals. These range from AIDS, SARS, to the various flu strains that have threatened us (e.g. H5N1 and avian flu). Animals, which may have harboured diseases for years, are now coming into contact with humans, often because of deforestation and land clearance to support growing populations.   Human activity [such as mining, logging, ‘slash and burn’ agriculture and road building, plus the demand for firewood] drives deforestation.  Deforestation means animals (like bats) are more likely to find ‘homes’ closer to human settlements. Sierra Leone lost much of its forest in the early part of the twentieth century.

Other diseases are known to be climate sensitive, such as malaria, dengue fever, West Nile virus, cholera and Lyme disease.  These are expected to intensify as climate change progresses, temperatures increase as do ‘extreme events’.   Malaria (caused by the protozoan - Plasmodium) has always been a significant killer, but it is expected that it will increase in range with climate change and the season for transmission (from Anopheline mosquitoes) will also increase.  Greater rainfall offers more places for the mosquito larvae to live and thrive.   By the same token, the mosquito (Aedes aegypti) that spreads dengue fever will be favoured by warmer and wetter weather.

Droughts or floods will affect crop yield, which in turn can result in malnutrition, so making people more susceptible to disease. Flooding can also provide not only breeding grounds for insects but can result in the contamination of water supplies with faecal matter, resulting in diarrhoeal diseases like cholera.

Dry conditions ‘creates’ fuel for forest fires that end up fragmenting or destroying forests and woodlands.   This last year or so has seen some extreme examples.  Australia is no stranger to fire; bushfires have been known for thousands of years by the indigenous peoples (often triggered by lightning strikes).  These last few months have seen fires that are unprecedented in scale and ferocity; and the ‘bushfire season’ is not yet over.

Whereas in the past, bushfires were mainly associated with grasslands, burning non-woody herbaceous plants, the fires this time have affected areas where fire has rarely burned in the past, including rainforests, wet eucalyptus forests, and dried-out swamps (where the water table has dropped). Areas rich in Eucalypts are more likely to catch fire because of the volatile and highly combustible oils produced by their leaves.

The litter beneath these trees is rich in organic compounds such as phenols. These slow down the microbial breakdown of the litter and dead leaves,  so a layer of dry, combustible material accumulates.  Some five million (plus) hectares of land has already been burnt.  Vast tracts of forests, woodlands, trees, shrubs and grasslands have been consumed by the fires.

The fires have been fuelled by

  • The extreme heat,
  • A prolonged drought  (Australia has experienced one of the driest Springs since records began over a hundred years back) and
  • Strong winds.

These hotter and drier conditions are associated with climate change and have made the country’s bushfire season longer and much more dangerous. Record breaking temperatures have been recorded and mid-December saw the hottest day ever recorded (an average temperature of 41.9 C.  The hot weather was also accompanied by strong winds which fanned the flames, spread the fires and blew smoke across major cities.

Australia is not the only country affected by fires. Sweden has a lot of forest and woodland, much of it dominated by Spruces and Pines.  Again recent record breaking temperatures and drought across many parts of Europe have put large areas of Swedish forest at risk. Rainfall in Sweden in 2018 was been dramatically down - approximately a seventh of the normal amount. In Summer 2018, there were some 50+ fires burning from the extreme north down to Malmo in the south.  

Summer 2019 saw fire affecting thousands of square miles of boreal forest in Russia.  Russia has the largest area of forest in the world; it covers some 40+ % of the country.  Much of thi forest is remote and difficult to reach which creates particular problems when trying to control the fires.  Strong winds spread the smoke and ash across the country; it affected cities such as Novosibirsk and Krasnoyarsk (each home to a million people).

woodland and forest as seen from the Trans Siberian railwa

woodland and forest as seen from the Trans Siberian railway

There have also been recent fires in the Amazon; these forests are often described as ‘the lungs of the world’.  Fires in this region are to be expected during the ‘dry season’, but there has been the suggestion that some fires were deliberate (clearing for agriculture or mining ?). [The BBC published an interesting graphic of the fires.]  Whilst some ecosystems ‘benefit’ from periodically experiencing fire - as it allows for regrowth; this is not the situation in the Amazon. The tropical forests of the Amazon have no adaptation to fire and suffer immense damage in consequence.

The fragmentation and the loss of forests / woodlands (across the globe) has been a concern for many years due to its effects on biodiversity and ecological processes.  Fragmentation of woodlands and forests can be the result of;

  • Farming and agriculture
  • Timber extraction
  • Construction of motorways / railways
  • Housing
  • Mining

To these human directed activities, we probably can now add anthropogenic climate change.

* others have implicated volcanic activity.

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RSPB’s Big Garden Birdwatch : 2020 https://www.woodlands.co.uk/blog/flora-and-fauna/rspbs-big-garden-birdwatch-2020/ https://www.woodlands.co.uk/blog/flora-and-fauna/rspbs-big-garden-birdwatch-2020/#respond Tue, 14 Jan 2020 16:15:06 +0000 https://www.woodlands.co.uk/?p=32500

This year the weekend of 25th - 27th January, sees the return of the RSPB’s Big Garden Birdwatch. If you would like to take part, you need to put aside an hour at any time over the three days and count the birds visiting your garden or a local park.  

If you go to the  www.rspb.org.uk website, you can ‘sign up’ which will unlock exclusive Birdwatch Extra features.

What is involved if you take part ?

During the course of the hour, you are asked to record the highest number of each bird species actually in your garden / park (not just passing by).    If you see other animals in your garden or park you are asked to note these down as well.   It all helps to build up a picture of how our wildlife is faring. 

The Big Garden Bird Watch has been running for a number of years and has helped build a picture of how various bird populations have changed over recent times. For example, in 1979, the song thrush was in the top ten of birds seen but last year it had fallen to number 20 in the list - a decline of of 76%.  The information from the survey helps ecologists monitor bird populations and understand the pressures on wildlife.

Our local educational charity (Bell House in Dulwich) has a large garden and volunteers there will be monitoring the 'visitors' for the Garden Birdwatch.  Sharon has kindly supplied the images used here - taken in the garden.

]]> https://www.woodlands.co.uk/blog/flora-and-fauna/rspbs-big-garden-birdwatch-2020/feed/ 0 Climate change – adapt or die ? https://www.woodlands.co.uk/blog/flora-and-fauna/climate-change-adapt-or-die/ https://www.woodlands.co.uk/blog/flora-and-fauna/climate-change-adapt-or-die/#respond Sat, 11 Jan 2020 00:24:16 +0000 https://www.woodlands.co.uk/?p=32452

Summer 2018 saw my garden filled with colour, the sunflowers grew tall, the sweet peas colourful and scented and my ‘exotic’ red castor oil plants were almost tropical in appearance.  However, this last summer was very disappointing - many things failed to thrive or were dwarfed - not doubt in response to periods of wet and cold in the earlier months of the year.  Whilst, it is very clear that plants and animals respond to their environment and the weather that they experience, it is not clear how they respond to the long term effects of climate change.  As yet, we do not have many answers to this.  We need to understand how both plants and animals can 

(1). respond or indeed adapt to changes in climate - i.e new conditions.  For example, can they change in terms of size or shape         or 

(2). change the timing of ‘life events’ - e.g. metamorphosis such as the emergence of mayflies, when eggs are laid (much recorded by phenologists).

It is also important to determine if such changes affect their reproductive fitness; i.e. the number of offspring that they leave (their evolutionary fitness).

great titTo get answers to such questions involves long term and detailed studies of particular habitats and species.   One such study is that which has been running (since 1947) at Wytham Wood, just outside Oxford.  Wytham Wood is said to be the most intensely studied woodland in the world. The area includes ancient semi-natural woodland, secondary woodland, grassland and ponds.  It is a designated SSSI, where some 500+ plant species and 800+ butterfly and moth species have been recorded. 

Records of some of its bird populations go back some seventy or more years (starting with the work of David Lack). The populations of blue tits and great tits have been monitored - using hundreds of nest boxes, dozens of feeding stations and more recently by the micro-chipping of the birds.  The time of reproduction, the number of eggs laid and the weight and size of the birds have been measured over the decades.  All vital statistics to inform of any response to changing climatic conditions.  Harvard University also has its own woodlands at Petersham (in Central Massachusetts) – and these too have been been subject to intensive study.

Viktoriia Radchuk (at the Leibniz Institute for Zoo and Wildlife Research in Berlin) together with many other researchers has brought together many studies similar to the Wytham one - involving different species, but mainly birds;  and similar data sets.  Analysis showed that higher temperatures (associated with climate change in recent times) were moving life events earlier in the year.  Thus, birds are arriving at breeding sites earlier, breeding earlier, and the young are developing earlier. Seemingly, these changes in timing enable birds to breed more successfully.  However, though the birds are responding to environmental changes it may be that they are not able to respond fast enough in the longer term.  Many phenological events have moved forward in respond to climate change but not all.  Columbian ground squirrels are reported to emerge from hibernation later, and the migration of some birds has been delayed.  These changes are thought to lower the ‘fitness’ of the organisms.

At the moment, many  animals (and indeed plants) seem able to adapt to changes in climate - without moving to new areas.  However, in the longer term, whilst migration (extension of the range of a species) might be a possibility - this could be problematic with the increasing fragmentation and destruction of habitats (though farming, urbanisation, construction of roadways etc).  Whilst organisms are adaptable in so many ways, their amazing flexibility may not be enough to keep pace with the rapid onset of climate change that we have witnessed in recent years.

Thanks to Sharon for Great Tit image

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20 20 vision for 2020 – is even 20% tree cover enough? https://www.woodlands.co.uk/blog/climate-change/20-20-vision-for-2020-is-even-20-tree-cover-enough/ https://www.woodlands.co.uk/blog/climate-change/20-20-vision-for-2020-is-even-20-tree-cover-enough/#comments Mon, 06 Jan 2020 18:01:17 +0000 https://www.woodlands.co.uk/?p=32474

Campaigners say that we need to increase tree cover to 50% and claim it will help deal with climate change. Tree planting became a big issue in the recent general election but it's much harder than people think and probably less effective at combatting climate change than other simpler measures.   For a start it's a slow business - even in the 1960s tree-planting splurge it took a decade of feverish activity to increase tree cover by just a few percentage points.  Also you need to think carefully about where you plant and what trees you plant - the 1960's planting was mostly on uplands and with mono-cultures that were bad for biodiversity (mainly spruce and pine).  More fundamentally we need to ask what this tree-planting is trying to achieve: can the carbon fixed through one crop of trees realistically counter the burning of carbon from millions of generations of trees represented by burning coal and oil?

There is no substitute for reducing carbon consumption and anyway that would be a much easier thing to achieve.  A typical Brit consumes/releases 8 tonnes of carbon per year and obviously this isn't evenly distributed - the middle classes consume much more, in line with their wealthier lifestyles.  That compares with poorer African countries where consumption is a small fraction - a Somali produces less than a tenth of a tonne of carbon each year - so a Brit's consumption every 4 days is about the same as a Somali for a whole year.  A typical Pakistani has a carbon footprint of only a tenth of the average British person.  We need to cut consumption much more urgently than we need to plant trees.

Anyway, let's see how tree-planting in the UK might help.  According to the Forestry Commission there are about 3 million hectares of trees in the UK representing about 13% tree cover (more in Scotland and less in England).  Suppose we were to double that to 6 million hectares, how much carbon would the extra trees fix?  Assume an average "yield class" of 10, which means that each hectare adds 10 tonnes per year, this would fix a maximum of an extra 30 million tonnes of carbon each year - assuming you never fell the trees and that you opt for continuous cover management.  So that represents a maximum of half a tonne per UK citizen per year while we are consuming about 8 tonnes.  It would also be an enormous upheaval to plant that many trees in a short time.

Whilst some more centrally-planned tree planting is a probably a good thing here are three simple, but controversial, ways to increase carbon fixing through forestry and agriculture:

  • remove the subsidies for sheep farming.  There are far too many sheep, they do little else apart from eating and they stop the natural regeneration of trees on millions of acres of hillside - which will happen in their absence.  You'll get more trees without having to plant them and with natural regeneration they will grow where they "want to be"
  • reform the tax rules than make all timber income tax-free.  This concession was introduced under Margaret Thatcher and has the effect of encouraging forest owners to clear-fell their forests and to do it much too early.  This rule could be replaced by limiting the tax break on felled timber to only apply to woodlands that have "continuous cover". This could be accompanied by tax breaks for money spent on new planting.
  • refuse to give farming subsidies [of any sort] to farms which have less than 10% tree cover.  Obviously this would be phased in and farmers would need to be given plenty of support in getting new shelter belts and copses established.

Along with other measures that are being introduced this would increase tree-cover and boost the carbon fixing of existing ones.  By the end of the 2020s we could have 20% tree cover, but there is still no excuse for not reducing our excessive carbon consumption in the UK.

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The fate of Christmas trees https://www.woodlands.co.uk/blog/woodland-economics/the-fate-of-christmas-trees/ https://www.woodlands.co.uk/blog/woodland-economics/the-fate-of-christmas-trees/#respond Fri, 03 Jan 2020 12:10:45 +0000 https://www.woodlands.co.uk/?p=32460

There is considerable debate as to the virtues or otherwise of buying a real Christmas tree over an artificial one.  This comes into focus somewhat more sharply in the post-Christmas period.  

A  6 to 7 foot high natural tree (bought with no roots) would be between ten to fifteen years old and it has a fairly low carbon footprint.   As it has been growing, it has been absorbing carbon dioxide from the atmosphere and locking it away in the form of cellulose and lignin, whilst releasing oxygen.  However, this footprint changes dramatically if its fate is to be consigned to land fill.   As it decomposes, it will produce methane, a potent greenhouse gas and the carbon footprint of the tree will increase quite dramatically.   If, however, the tree is carefully composted, then its environmental impact can remain relatively low (visit the Carbon Trust for detail).  

The cultivation and growth of natural Christmas trees provides a wildlife habitat, and the trees help stabilise and protect soil.  But in some parts of the world, notably Canada and the USA, the growth and supply of Christmas trees has been affected by heatwaves (as in Oregon in 2017 / 2018 - which killed many very young trees), insect damage and wildfires. The effects of climate change are particularly marked in Canada.  It may be that climate change will intensify the effect of these factors, and that Christmas tree ‘farms’ may need to move to higher elevations - where it is cooler and insect pests (e.g. balsam twig aphid) are less of a problem. 

A artificial tree of similar size to a natural one has a much greater carbon footprint, mainly associated with the production of the different types of plastic  (such as polyvinyl chloride) used in its manufacture. PVC may also contain phthalates, which can accumulate in body tissues and are associated with damage to mammalian systems.  Whilst artificial trees can be used for a number of years - at the ‘end of their lives’,  they are difficult to recycle or repurpose. Plastic discarded into the natural environment is now recognised as a major problem. There is a further consideration - the ‘additional’ carbon footprint associated with the transport of artificial trees from their place of manufacture (often China, South Korea etc).

Further ‘food for thought’ and more detailed information on the pros and cons of natural and artificial Christmas trees  :






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January’s Fungi Focus: Witches’ Butter, Warlock’s Butter and Yellow Brain https://www.woodlands.co.uk/blog/flora-and-fauna/januarys-fungi-focus-witches-butter-warlocks-butter-and-yellow-brain/ https://www.woodlands.co.uk/blog/flora-and-fauna/januarys-fungi-focus-witches-butter-warlocks-butter-and-yellow-brain/#respond Wed, 01 Jan 2020 10:37:39 +0000 https://www.woodlands.co.uk/?p=32423

There are some who argue that the prime fungi hunting season basically comes to an end with the first frosts around November time. There is still plenty to see on those wintry woodland walks around the turn of the year however. In these mid to late winter months, the more conventional cap-and-stem types might be thinner on the ground, but if you care to cast your eyes around to more woody substrates, you should be sure to find a variety of crusts, brackets, tiny ascomycetes and, the subject of this month’s fungi focus, jellies.  Examples of fungi that form soft and gelatinous fruitbodies include the blobby types like Orange Jelly Spot (Dacrymyces stillatus) and Crystal Brain (Exidia nucleata) to more complex and distinctive fruiting forms like the branching Yellow Stagshorn (Calocera viscosa) and the subject of a former post, the Jelly Ear (Auricularia auricula-judae). 

One of the more distinctive jelly fungi, Calocera viscosa or the Yellow Stagshorn.

The fruitbodies, as regular readers of these posts will know, are really only the reproductive organs that release spores, with the main part of the fungi consisting of a filamentous network running through and feeding upon its chosen substrate. The examples cited above are all decomposers of dead wood, with the Jelly Ear primarily (although not exclusively) associated with elder.  There are also jelly fungi that act as parasites or decomposers of plants and other fungi, as the recently published two-volume Fungi of Temperate Europe highlights, and not all produce such obvious fruitbodies. Some occur as “almost invisible films on, for example, wood.” Even this mycological bible draws the line in excluding from its otherwise comprehensive pages those that “form resupinate, mostly invisible fruitbodies”, presumable acting on the assumption that unless you are a scientist equipped with all the correct tools and the knowledge of where to look, you’ll have no chance to finding them anyway.

There are a lot of species that fall within this massive category of the jelly fungi then. I shall, however, deal only with the more common and readily identifiable here to describe a few basic characteristics of their composition.

The Jelly Ear (Auricularia auricula-judae), one of the most common and easily identifiable of the jelly fungi.

Like other fungi, the fruitbodies are comprised of the long threadlike cells known as hyphae interwoven together, individually so thin as to be invisible without a microscope and a staining agent applied to the sample. In this case though, this network of hyphae is surrounded by a protective gel. What this effectively means is that jelly fruitbodies are remarkably durable and robust compared with other fungi. They can freeze solid, dehydrate, defrost and rehydrate and still maintain their visible form – although admittedly taking a bit of a battering in the process – and can persist for some time. This makes them the perfect candidate for a fungi focus during the colder months when many are most prevalent, although most can be found during damp spells throughout the year.

The basidia, the microscopic reproductive structures emerging from the hypha that produce the spores, are longer than those of most other fungi. They are embedded within this gelatinous body, with the little prongs or horns that bear the spores (called sterigmata) protruding just above the surface. So basically the surface skin, or hymenium, of these gelatinous fruitbodies is where the spores are released from. If you wish to take a spore print, simply lay the fungus face down on a piece of black paper or a microscope slide: One of the things that seems to characterises the spores of the examples I’ve mentioned, aside from the fact that they leave white prints, is that they are relatively large and ‘allantoid’: that is, fat and sausage or banana-shaped.

The fat allantoid sausage-shaped spores of Exidia plana

In the interests of keeping things clear and simple, I had hoped to avoid much in the way of mention of microscopic details and Latin names in this and future posts. The latter in particular can be very cryptic and daunting to non-biologists (among whom I include myself, I should add!).  While the point of the Latin binomial names is to position the species in question accurately within a taxonomic tree-of-life that highlights its relationship with other similar species, one of the points of frustration I’ve heard from even the most seasoned of mycologists is that new genetic identification techniques have seen many types reassessed, reclassified and consequently renamed. 

Just to give an example, the aforementioned Crystal Brain, a near translucent blob with white crystalline grains contained within it, is still referred to on the British Mycological Society website as Exidia nucleata, drawing attention to its family resemblance to the slightly more opaque and crystal-less White Brain, Exidia thuretania.   However, Fungi of Temperate Europe, which only provides Latin names, lists it as Myxarium nucleatum. 

The White Brain, distinguished from the the Crystal Brain by the absence of crystals

The White Brain, distinguished from the the Crystal Brain by the absence of crystals

I cannot even begin to fathom the reasons for this renaming, and on my own side, I don’t really feel the need to care. For me, a Crystal Brain is first and foremost a Crystal Brain – a name that describes how it looks. However, I am using this example to introduce another similar type whose common name, Witches’ Butter, goes to show how these more instinctive and traditional English descriptors can be vague and imprecise and mean very different things to different people.

Sticking “Witches’ Butter” into Wikipedia amply demonstrates the problem, with the site claiming the term can refer to ‘Exidia nigricans, a black, gelatinous fungus; Exidia glandulosa, a black, gelatinous fungus; Tremella mesenterica, a yellow, gelatinous fungus; Dacrymyces, a jelly fungus often confused with Tremella; Nostoc, a genus of gelatinous cyanobacteria” – i.e, this last one isn’t even a fungus!

Nostoc, a cyanobacteria with a gelatinous sheath that is not even fungal in nature is also referred to as Witches' Butter

The BMS website states that Witches’ Butter is the common name for Exidia glandulosa, while the Dictionary software sitting on my Mac desktop describes it as “a black gelatinous European fungus which forms folded cup-like masses on dead wood. Exidia plana, family Tremellaceae, class Hymenomycetes”: Exidia plana is a synonym for Exidia nigricans, whose given common name according to the BMS is Warlock’s Butter.

A partially dried out patch of Exidia plana, either Witches' Butter or Warlock's Butter, whichever you fancy.JPG

Confused? Well, what we can at least say is that whether applied to Exidia glandulosa or Exidia plana/Exidia nigricans, Witches’ Butter usually refers to a semi-translucent black or dark brown jelly-like excrescences that appear on dead or dying standing or fallen trees and branches.

Exidia glandulosa is described by Fungi of Temperate Europe as “turbinate”, with a hairy upper side and “a more grey-black, finely warty lower (hymenial) lower side” (i.e. the surface containing the basidia from which the spores are released). Michael Jordan in The Encyclopedia of Fungi of Britain and Europe describes a “contorted disc-shape”. Pat O’Reilly on the First Nature website writes that “individual fruit bodies grow to between 1 and 2cm across, sometimes coalescing to create larger masses typically 3 to 10cm across”. In drier times, these fruitbodies are a lot harder and shrivelled, but “are revived in wet weather and regain their expanded shape and gelatinous texture.”

The fusing blobs and brain-like folds of Exidia plana.

Exidia plana/nigricans, which seems to be a lot more common around my particular neck of the woods, might initially look as similar as to effectively be treated as the same thing. Even down at microscopic level, the spores are the same allantoid sausages and pretty much the same size, at 12-17 x 4-5 microns. The key difference, which is quite obvious in most cases, is that the jelly bodies tend to spread wider and eventually fuse together, rather than appear as the “irregular flattish-faceted separate blocks of black jelly-like material” of E. glandulosa described by First Nature .  All of the sources cited above mention its brain-like wrinkles and folds.   And to confuse matters further, Fungi of Temperate Europe also lists a certain Exidia pithya, which forms a thinner layer of tar-black jelly but is only found on conifers, and mainly on fallen spruce (Picea).  I think most of us would be quite content in overlooking these subtle differences and ignoring the Latin names to just settle with calling all of them Witches’ Butter.

Buttery black blobs of Exidia plana, aka Exidia nigricans, aka Warlock's Butter, aka Witches' Butter.JPG

But where did this common name come from anyway? An older book, The Romance of the Fungus World (1925) by R. T. Rolfe and F. W. Rolfe, after referencing the alternative folk name of Fairy Butter and mentioning its “buttery” (?) appearances, cites an even earlier text, R.C.A. Prior’s On the Popular Names of the British Plants (1863), as stating its “unaccountably rapid growth in the night, which has given rise to a superstitious belief, still prevalent in Sweden (where it is called “troll smör” or Troll’s Butter), that witches (and trolls) milk the cows and scatter about the butter.”

This Nordic connection was noted even further back in 1777, in John Brand’s Popular Antiquities, which notes that in Sweden it was believed that the devil gave witches “a beast about the bigness and shape of a young cat, which they call a carrier. What this carrier brings they must receive for the devil. These carriers fill themselves so full sometimes, that they are forced to spew by the way, which spewing is found in several gardens where Colworts grow [i.e. cabbages], and not far from the houses of these witches. It is of a yellow colour like gold and is called ‘Butter of Witches.’”

Golden blobs of cat spew on cabbages sound more likely to be the slime mould Fuligo septica, (aka Dog’s Vomit Slime or Flowers of Tan), than any of the dark-coloured Exidia jelly fungi species found growing on dead wood. 

There is, however, one further jelly fungus that is “of a yellow colour like gold” and sometimes also referred to as Witches’ Butter, as noted by Wikipedia, although this time it is in the Tremella rather than the Exidia genus. This is the Yellow Brain Fungus (aka Golden Jelly). To add further to the confusion, this kind of Yellow Brain / Witches’ Butter actually describes two different species that look more or less identical. 

Tremella mesenterica, one of the two jellies known as Yellow Brain Fungus, and one of many referred to as Witches Butter

Essentially their fruitbodies are lobed or pustular semi-translucent swellings with folds and bumps that are slightly more pronounced than the Crystal Brain, White Brain, Warlock’s Butter (E. plana/nigricans) and “real” Witches’ Butter, E. glandulosa.   Aside from the colour, and the fact that under the microscope their spores are small and round (not big and bendy), the crucial difference is that while you will find them both growing on dead deciduous wood such as fallen tree trunks or branches, they are actually parasitizing another fungus that is already decaying the wood.  In the case of Tremella mesenterica, the Yellow Brain is actually growing on the mycelium of the corticioid crust fungus in the Peniophora genus, which are decomposers that manifest themselves as smooth, tough waxy patches of grey tinged with beige, red or violet, depending on the species. 

Tremella aurantia, meanwhile, looks virtually the same, but its main host is another more conspicuous resupinate, which I covered last year, the Hairy Curtain Crust (Stereum hirsutum). (It also apparently has a taste for other Stereum species too).   Basically, if you find a pile of logs with Hairy Curtain Crust growing from them, have a look around, and any yellow brain-like blob you find will most likely be Tremella aurantia, while if there’s a greyish leathery patch growing on the wood surface, it’s probably Tremella mesenterica.

The grey patches of what might be a Peniophora resupinate fungi suggests this Yellow Brain is probably Tremella mesenterica.JPG

Either way, you’ll probably just want to avoid confusion and just call it Yellow Brain (to add insult to injury, Fungi of Temperate Europe has given T. aurantia another name, Naematelia aurantia).  Or add to the confusion and refer to it as Yellow Witches’ Butter. You might not be wrong in either case, but you should be able to see now how complicated the relationship between common names and Latin names can be with the particular fungus they might be applied to.

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Climate change changes phenologies. https://www.woodlands.co.uk/blog/flora-and-fauna/climate-change-changes-phenologies/ https://www.woodlands.co.uk/blog/flora-and-fauna/climate-change-changes-phenologies/#respond Thu, 26 Dec 2019 12:03:37 +0000 https://www.woodlands.co.uk/?p=32130

Phenology is about observing natural events and recording when things happen.   For example, when ash or horse chestnut trees come into leaf, when the first swifts are sighted or bumblebees emerge from their nests. These timings vary from year to year. By recording such events over many years, it is possible to look for trends and see if they are associated with changes in the weather or other phenomena.

Climate change has resulted in significant changes in summer and winter temperatures, and rainfall patterns.    For example,  April, May and June of 2018 were all very warm, each being at least 1.9°C above average [that is the 30 year average for 1961–90]; June was the third warmest June for the UK since 1910.

Such changes can affect different phenologies in different ways. A concern with these changing phenologies is that ‘mismatches’ can occur.   For example, when trees come into leaf determines when caterpillars will be able to feed and that in turn affects when birds can feed on the caterpillars and raise their young.  If these events do not occur in order / sequence then the ‘balance of the ecosystem’ is disturbed. 

Warmer weather in Spring has changed the breeding behaviour of birds such as blue tits.  They breed earlier.  The birds' reproductive behaviour is influenced by night time temperatures in Spring; colder temperatures delay the building of nests and egg laying.   So with warmer weather, their breeding pattern is advanced.  Their egg laying is also influenced by the leafing of trees, particularly birch.  The caterpillars on which the chicks feast are also reaching their peak earlier.  The peak of caterpillar abundance is short lived and needs to coincide with the time when the chicks are hungriest.

Migratory species that feed on insects also need to time their arrival to coincide with emergence of caterpillars etc.

Changes in the breeding behaviour of birds (associated with climate change) have also been observed in the Southern Hemisphere.  Again,  warmer temperatures in their early spring means that Australian Fairy-wrens will start breeding earlier; and if temperatures rise too high by mid-summer, they will finish breeding earlier.

The effects of climate change can be seen in phenological events across the globe.

(Thanks to Sandy for jpg of Fairy Wrens)

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Seasonal Fruits for Christmas https://www.woodlands.co.uk/blog/flora-and-fauna/seasonal-fruits-for-christmas/ https://www.woodlands.co.uk/blog/flora-and-fauna/seasonal-fruits-for-christmas/#comments Fri, 13 Dec 2019 00:51:10 +0000 https://www.woodlands.co.uk/?p=32232

Winter, and Christmas in particular, is linked with foods and flavours that perhaps we do not experience at other times of the year.  Think of the distinctive smell and taste of the Christmas Pudding with its many ingredients, the cranberry sauce with the turkey, mince pies (with their mixed fruits) and perhaps exotic crystallised figs; all examples of seasonal fare.   The ingredients for some of these may be raised in your garden or come from much further afield.  

If we look back in time, then our ancestors would have gathered, stored, and preserved a wide range of foraged fruits and ‘seeds’ to ‘see them through’ the harsher winter months.  They had techniques and recipes for preserving fruits / roots etc. through the winter when fridges and freezing had not been thought of; except for the ice houses on the estates of the landed gentry. In relatively recent times, there has been renewed interest in foraged food such as chestnuts, sloes etc - see Richard Mabey’s book “ Food for Free." 

Currently there is interest in encouraging consumption of locally produced and seasonal foods, rather than relying totally on imported foods or those that have to be grown in heated greenhouses.  Reducing our reliance on imported food means what we do eat will have fewer ‘air miles’ and a lower carbon footprint.   However, many farmers in poorer countries rely heavily on the demand for their ‘exotic’ produce, such as out of season avocados and soft fruits, and indeed flowers.  Significant areas of food production in the UK, such as in Kent, are now covered with polytunnels and heated greenhouses, growing out-of-season fruit and vegetables to meet our desire to have such food available all year round.

One fruit that can be gathered in the wild is the cranberry. Our native cranberry (Vaccinium oxycoccus) has quite small berries and needs to be picked by hand. It tends to grow in wet, northern moorland areas. However, the cranberry sauce for the turkey is likely to be made from the North American species V. macrocarpon - which has bigger berries and can be harvested mechanically.  Botanically related is the bilberry (Vaccinium myrtilus).  These used to be collected in some quantity for pies and jam, but have been largely superseded again by the larger American blueberry (Vaccinium corymbosum). 

In Sweden - the lingonberry or cowberry (Vaccinium vitis-idaea) is found in their boreal forests and the artic tundra.  The berries are quite ‘sharp’ and are usually cooked and sweetened to make a jam or compote.  Lingonberries also contain benzoic acid, which acts as a natural preservative in the jams and other preparations. Lingonberry sauce or jam may be served with meat (from reindeer) or meatballs.  A swedish dessert served at Christmas is the lingonpäron, which is made from pears - peeled and boiled and served in lingonberry juice (lingondricka). 

sloesAll of these berries offered a source of Vitamin C during the winter months when little else was available. Rose hips were also collected and made into a syrup - which was another good source of Vitamin C,  aka ascorbic acid .  Vitamin C helps the body make collagen, which has a vital role in the skin and connective tissues; it protects the body from scurvy.  

Another winter fruit was the sloe from the Blackthorn (Prunus spinosa).  Sloes are much used in the making of sloe gin, though they can also be used to make jams & chutneys.  Other winter fruits included crab apples, haws (from hawthorn), service berries (from Amelanchier sp) and medlars.  Both medlars and service berries need to “blet” (rot) before they can be eaten - their somewhat special taste becomes tempered by the first frosts of autumn. Quinces may also be subjected to bletting by frost. However, they can also be cooked or roasted and then used for jams, marmalade, jellies, or puddings.

Apart from such homegrown fruits. Christmas used to be a time when other more ‘exotic’ foods were available.  These might have been the oranges in the children’s stockings, or dates, mince pies (filled with dried fruits and spices), cakes with marzipan (made from almonds) and icing.  Now, as mentioned, we expect world-wide and ‘seasonal’ produce to be available all year round.

With thanks to Fredrika for jpgs of freshly collected blueberries and the 'Lingon Grova' van in Stockholm..

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Christmas quiz with prize for the first 40 valid entries https://www.woodlands.co.uk/blog/reviews-puzzles/christmas-quiz-with-prize-for-the-first-40-valid-entries/ https://www.woodlands.co.uk/blog/reviews-puzzles/christmas-quiz-with-prize-for-the-first-40-valid-entries/#respond Mon, 09 Dec 2019 09:54:12 +0000 https://www.woodlands.co.uk/?p=32311

Christmas is a good time to go for a woodland walk .... and for presents.

For children, there's nothing better as a motivator than a quiz.

So we are offering to send entrants a prize of a woodlands notebook and tree poster which we will post to you as soon as we get your entry if it's valid - maximum 40 prizes.

The quiz: Take a photo of any 6 (any six) of these:

  • A gastropod
  • A leaf with a tooth edge
  • A leaf with parallel veins
  • A fern frond
  • A beetle
  • A named conifer
  • A bracket fungus
  • An amphibian
  • An earthworm
  • A samara (winged fruit)
  • A lichen
  • A leaf with spines
  • A named yellow flower
  • A fruit or seed dispersed by an animal
  • A fungal fruiting body
  • A cone from a conifer
  • A one-seeded fruit
  • A nettle or  a dead nettle
  • An oak tree
  • An arachnid
  • A woodlouse
  • A compound leaf
  • A plant gall


Please post or email your photos to us at:

melanie@woodlands.co.uk Woodlands.co.uk,

19 Half Moon Lane, London SE24 9JU

Don't forget to give us your postal address!

Happy Christmas!


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German forest dieback : waldsterben 2 https://www.woodlands.co.uk/blog/flora-and-fauna/german-forest-dieback-waldsterben-2/ https://www.woodlands.co.uk/blog/flora-and-fauna/german-forest-dieback-waldsterben-2/#respond Fri, 06 Dec 2019 00:35:36 +0000 https://www.woodlands.co.uk/?p=31932

In recent times, new or different threats have emerged to upset the balance of woodland and forest ecosystems.   In the 1960’s and early 70’s concern focussed on the effects of air pollution, particularly the effects of acid rain.  This type of pollution was characterised by the deposition / assimilation of sulphur dioxide and its derivatives (sulphuric & sulphurous acid), plus various nitrogen oxides.  This air pollution was largely due to industry and traffic.

Some of the most striking effects of ‘acid rain’ pollution were seen in the coniferous forests of Germany - where it was termed : Waldsterben [Wald=forest plus sterben=to die].  The various sulphur and nitrogen compounds in the air not only caused dieback of the trees, but also damaged the lichen flora of the bark, trunk and branches.  The loss of lichens from industrial regions had been noted back in the 19th century but was examined in detail by Gilbert (Lichen deserts) in the 1960's & 70’s around Newcastle in the U.K.

German forests are again suffering from dieback [or Waldsterben 2] but this time the damage has been associated with climate change (drought, intense heat,  fires and storms) plus bark beetle infestations.  A walk through some areas will reveal dead spruces and beech trees.  The German Ministry of Food and Agriculture has said that the forests need quick help’ and has proposed a large scale clear up and re-afforestation program. 

This is a strategy which has been employed before but it has its critics.  The removal of dead wood has significant affect on the insect and fungal populations that are dependent on deadwood.  Decomposing wood allows saproxylic beetles to flourish, plus woodlice and springtails - and many different species of fungi. A more open  woodland would also allow birds of prey (owls etc.) to hunt for small mammals.   The creation of extensive stands of dense forest with similarly aged trees is an ‘invitation’ to disease, pests and greater susceptibility to weather events. 

There is a further argument for leaving gaps in the canopy of the woodlands and forests to enable the regrowth of native tree species - as these would help increase the resistance to extreme weather events (resilience).

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