Forests across Europe occupy some 40% of the land area, and until recently they were regarded as not only a source of timber but also an important ’sink’ of carbon.  That is to say, they took in more carbon dioxide in photosynthesis (and stored it away in complex organic compounds) than they released in respiration. However, in recent times, these important biomes have turned from carbon sink to carbon source.  This year, the Finnish forests changed from sink to source.  Forests in the Czech Republic and Germany also released more carbon than they absorbed.  Though French forests are still a sink, their absorption of carbon dioxide has roughly halved in recent years (from 74 million tonnes of CO2 to 37.8 million tonnes in 2022).   Norway has seen a similar reduction in carbon dioxide storage from 32 million tonnes to 18 million tonnes. Seemingly, forests across the continent are losing the ability to act as carbon sinks, but why?  One reason seems to be the increased harvesting of timber,  many forests are privately owned and run on a commercial basis.  The Russian invasion of Ukraine has been a factor as sanctions against Russian timber has lead to more ‘domestic’ culling, for example in Finland.  However, climate change is an important factor in this downturn.  In recent times, droughts (in 2018 and 2022) have had a significant effect of forests, trees are stressed and the effects of drought have been greater than anticipated.  Drought can also be coupled with other extreme weather events (such as storm damage) and outbreaks of bark beetle (which have particularly affected spruce woodlands).  The Czech Republic has reported several outbreaks of bark beetle in recent times. What can be done to mitigate this loss of carbon sinks? Clearly reducing the harvesting of trees for timber and the banning of clear felling would help.  After a clear cut in a boreal or temperate region, it can take a forest 10 to 15 years to become a sink again, and even longer for the original emissions associated with the clear cut to be compensated for. Increasing the diversity and resilience of trees used in forestry is another approach to increasing CO2 absorption, however, it would take some time to determine which trees would be most effective in creating a carbon sink in the face of climate change.  Sadly, it is also the case that many tropical forests are in decline in terms of carbon storage due to deforestation,  expansion of agriculture and fires. Further reading : https://forest.eea.europa.eu/topics/forest-and-climate/carbon-sinks-and-sources  

Willow bark and the covid virus. The Covid pandemic created great strains on health and business services, and the virus continues to impact society in many ways.  It is not surprising that there is an ongoing search for anti-viral agents. Finnish scientists have found that willow bark may have a role to play. Willow bark has been used as a natural medicinal product over the centuries as an effective agent to treat pain and inflammation.  The anti-inflammatory properties of the bark are generally ascribed to salicin, which was to lead to the development of acetylsalicylic acid, that is aspirin.  The Finnish scientists ground up the willow bark in hot water and then sieved it to create an ‘extract’.   This solution was then added to a number of cell cultures that were exposed to different viruses (enteroviruses, a seasonal coronavirus and SARS CoV2).  They then monitored the viral activity, cell infection and viral replication  The extract had an effect on all of the viruses.  In some cases, the extract affected the envelope of the virus (a structure surrounding the viral genetic material) so the viruses essentially broke down, whereas others were prevented from releasing their genetic material and reproducing.  Specifically, though the Covid-19 virus could enter cells when treated with the extract, it could not reproduce once inside. The research team analysed the extract’s chemical composition and tested some known constituents of bark but concluded the success of the extract probably resulted from the interactions of different biologically active compounds.  Compounds in the extract included many complex chemicals (for example, hydroxycinnamic acids, salicylates, flavonoids, flavan-3-ols, and proanthocyanidins (polyphenols).  Further work will focus on the role / interactions of these various compounds. The Hazel Dormouse in peril. The numbers of the hazel dormouse have fallen dramatically since the turn of the century.  The dormouse has disappeared from Staffordshire, Northumberland and Herefordshire in the last few years.  This loss is attributed to The destruction / fragmentation of their habitats Poor management of woodlands and hedgerows, leading to a loss of diversity / niches Rising deer numbers, feeding on saplings and shrubs Extreme weather patterns may also play a part Captive-bred dormice have been re-introduced to some 25 sites in 13 counties across the country, sadly nine of these reintroductions were not successful.  Dormouse bridges have been created to enable the animals to move between areas dissected by major roads (such as the M1), others are planned.   The dormouse (Muscardinus avellanarius) is a nocturnal animal and lives mainly in deciduous woodland,  it feeds among the branches of trees and shrubs. the dormouse rarely descends to the ground.  It feeds on a wide variety of 'foods' ;  flowers (nectar and pollen), fruits (berries and nuts), certain buds and leaves and some insects, such as aphids and caterpillars. The hazel dormouse is regarded as a ‘flagship species’, that is to say, if the dormice are thriving then it is likely that other species are too from butterflies to birds such as the nightingale.  Dormice are currently assessed as ‘Vulnerable’ to extinction in Britain under IUCN Red List criteria, but recent studies suggest a classification of ‘Endangered’ might be more appropriate.  Certainly, their future is uncertain. Detailed information on the hazel dormouse is available at PTES (note this link opens a PDF).  Their report details the state of hazel dormice in 2023. zsaqwa https://youtu.be/4u-yMkXOuTY Changes in the Boreal Forests. Boreal forests encircle the northern reaches of the Earth, lying just below the treeless under of the Arctic.  These forest cover large areas of Alaska, Canada, Scandinavia and Siberia.  These forests contain billions of trees, most are conifers but birch, poplar and aspen may also be found.  The trees (and soils) contribute significantly to the cycling of carbon in nature, absorbing carbon dioxide in photosynthesis. They are also home to many species of migratory birds, plus predator species such as lynx and brown bears, and wandering herds of moose. Due to the remoteness of these forests, they have remained (until relatively recently) unaffected by human impact.  Now these forests are warming at a rate above the global average.  This has a number of effects:  In the southern parts of the boreal forest. Conditions are becoming too warm for cold adapted trees; their growth is slowed and they may die. With the warming comes increased dryness, which leads to water stress and increased risk of insect attack /  infestation. The dryness also means that forest fires are more likely and occur with increased ferocity.  This year, the fires in Canada have been particularly extensive and damaging.  Some 18.5M hectares went up in flames.   The plumes of smoke spread far and wide. [caption id="attachment_40597" align="aligncenter" width="675"] Canadian forest fire[/caption] Scientists are now using satellites to track changes in the extent of the boreal forests.  If trees are being lost on the southern edge of these forest, then it might be expected that the northern limit for tree growth might change.  Indeed, there is some evidence for this in Alaska where young Spruce are now growing some 25 miles beyond the previous tree line, moving into the ‘treeless tundra’.  It may be the loss on the southern edge is compensated by extension of the most northern parts of the boreal forest, but it is not clear whether tree can ‘move’ at the rate of climate change.  

In 2018, the blog reported on the extensive fires in Sweden, a country noted for its forests and woodlands, which cover approximately half of the country. Once the trees were mainly broad leaved species, but then oaks and alders began to decline.  By the middle of the  twentieth century,  Spruces and Pines were dominant.  This was mainly due to forestry management, to produce wood for fuel, charcoal [used in iron smelting], potash, tar and timber (for building). Fires burnt from the extreme north down to Malmo in the south. These fires affected some 20,000 hectares and destroyed woodlands valued at [circa] £50 million.  Now work by scientists at Uppsala University, the Swedish University of Agricultural Sciences (SLU), and the Swedish Meteorological and Hydrological Institute (SMHI) have examined the effects of the fires (of 2014) in the Vastmänland province, where the fires were ferocious, burning down into the soils. They have found that the 'forested areas' continued to lose carbon for several years after the fire, and that nitrate and phosphate input to streams and rivers increased after the fires. This spring and summer have again witnessed intense and widespread fires across the Mediterranean region, Canada and the United States. Fires are a problem not only because of their immediate destructive potential, but because they result in the release of carbon dioxide - which further contributes to global warming and climate change.  The United Nations Secretary-General said recently “The era of global warming has ended; the era of global boiling has arrived.” Data on these fires is not available as yet, but studies of the boreal fires in 2021 suggest those fires released some 1.76 billion tonnes of carbon dioxide into the atmosphere.  The fires contributed nearly one quarter of world wide carbon dioxide emissions from fires in that year.  [caption id="attachment_35352" align="aligncenter" width="650"] Woodland recovering from a fire[/caption] Boreal forests store roughly twice as much carbon in their trees and soil as tropical forests.  These forests (often referred to as the Taiga) surround the Arctic Circle and research suggests the Taiga is warming faster than the global average, so areas like Northern Canada and Siberia now experience more heat and drought than in the past, and consequently are more likely to suffer from fires. Clearly, when there is a fire, carbon dioxide (and many other carbon compounds eg soot / small particles) are released by the burning of the trees but there is also the effect of fire on the soil and its organic content - the humus.   Research indicates that during the fires in the boreal area some 150 tonnes of carbon dioxide may be released into the atmosphere per hectare.  Furthermore, even after the fire, carbon continues to be lost from the soil.  It may take some three years for carbon uptake by the soil to be recorded.   Fires also lead to the rapid loss (leaching) of nutrients (e.g. phosphate) to local lakes and rivers - as there is little or no vegetation to absorb the nutrients.   Rainfall is not intercepted by vegetation and so the flow of streams increases ( sometimes by 50%).    A research paper produced by the Desert Research Institute (in Nevada) has indicated that smoke from the burning of pines has the effect of making soil particles more water-repellent.  This repellency of smoke-affected soil particles could help explain the increased flooding, erosion, and surface runoff in fire damaged areas.  

Across the world forests and woodlands are under threat,  suffering  fragmentation and shrinkage.  This is not good news for the plants and animals that rely on these habitats for their survival.   In a large forest or woodland, animals can move around over considerable distances in search of food / partners - without having to leave the area that supports them.  Similarly, plant seeds when dispersed are more likely to find the micro-climate that they need for germination and subsequent growth (humidity, shade, soil type etc).  Some species have very ‘exacting’ requirements that can only be met in the heart of a forest or woodland.  For example, there is a frog that is restricted to undisturbed mountainous forests in Borneo. Sadly, recent surveys suggest that many forests continue to suffer from fragmentation / loss of area.  The two main reasons for this loss are : clearance for agriculture (palm oil plantations etc) - this has mainly affected tropical and sub tropical area.  Sometimes fires are used as a deliberate ‘tool’ to clear an area of forest so that the area can then be used for agriculture. wild fires - these have affected the Boreal Forests but also regions of the Amazon Basin.  In areas like Siberia and Canada, drought and high temperatures have lead to extensive fires. (Zombie fires are underground peat fires that smoulder in the winter months but reignite when the ground dries in the Spring or Summer.) Recent times have seen extensive fires across Siberia, Canada, parts of the West Coast of America and Australia. Woodlands have experienced fragmentation due to the expansion of agriculture, the building of motorways & roads, and the expansion of housing.  Wild flower meadows have suffered even more dramatically - with some 90+% lost in relatively recent times. Obviously fires are devastating locally, killing vast numbers of animals and plants. Fire also destroys the organic content of the soil and its complex microbial population.  The plumes of smoke released by fires (such as those seen in Canada and Australia) spread extensively.  The Canadian fires (883 fires raging at one point) left mile after mile of blackened forest, and forced hundreds of people from their homes.  The smoke spread far beyond Canada’s borders, as far away as parts of Europe.  New York City was ‘bathed’ in an ‘orange haze’ and experienced a hazardous level of air pollution. The plumes from such fires are rich in black carbon soot.  The soot particles absorbs solar radiation, keeping heat in the atmosphere. Recent analysis of smoke plumes indicates that there is also ‘dark brown carbon’.  This consists of a previously unknown type of particle and whilst these particles absorb less light per particle than black carbon, they are approximately four times as many brown carbon particles in wildfire smoke (compared to black soot particles).  There is also the suggestion that these brown particles retain capacity to absorb solar radiation for longer.  

At the end of the last Ice Age, the British Isles were recolonised; plant and animal species from the continent moved across the 'land bridge’ (doggerland) that connected us to Europe.  Trees, shrubs and plants began to move into the areas ‘released’ from the ice sheets, forests formed in many places.  At first, the forests were largely coniferous and they extended across the north of the UK to swathes of Europe and Asia: they formed an enormous area of boreal coniferous forest.  This vast array of trees provided shelter and food for a variety of animals -  wolves, lynx, elk and many other species.  Since the Ice Age,  forests and woodlands have been cut down for farming; trees felled for timber, sheep and deer ate young shoots and stopped native trees (like the Scots pine) from re-growing. Read more...

Holly and ivy have seasonal connotations, and due to climate change they are probably looking quite lush and vigorous at present.  Studies have shown that in recent times, holly has spread further north in Europe than ever before - ‘pushing forward’ by some eighty miles since the 1960’s.  Ivy too is on the move, growing vigourously.  However with both plants, their growth can come as a threat to other woodland species, smothering some (Ivy can grow to great heights using its tiny adventitious roots) or when growing horizontally it can affect the herb layer. https://www.theguardian.com/science/2020/dec/16/plantwatch-holly-ivy-and-how-warmer-weather-boosts-christmas-plants Read more...

During the last Ice Age, much of the UK was covered with a layer of ice up to kilometre deep, or by enormous glacial lakes. Certainly in northern parts, there was no vegetation as glaciers scraped their way across the landscape.  So much water was locked up in the glaciers that sea levels dropped dramatically; we were connected to Europe by areas such as Doggerland.  Details of the glaciation and its effect can be found on the BRITICE site.  When the ice age came to an end some eleven thousand years ago, plants, animals and humans migrated back to the previously frozen and inhospitable land.  Over time, large forests and woodland areas developed.  In the North, boreal forest grew up - represented today by the remaining Caledonian Forest.  Further south, there was the wildwood (as described by Rackham and others). The wildwood was probably a complex and tangled mixture of different trees, with many of the trees either dead or dying through the effects of wind, fire (lightning strikes) and flooding. It would have offered a vast variety of habitats and niches for plants, insects and mammals. Read more...

Forests and woodlands are important in the global ecosystem; they have taken up some 20 to 30% of the carbon dioxide released from fossil fuels in recent times. It had been assumed that the dense and biodiverse tropical forest ecosystems (close to the equator) were particularly effective in ‘soaking up this carbon dioxide’.   However, there is doubt that this will continue to be the case as forests shrink in size.  Plus, recent work at the University of Birmingham (Dr Tom Pugh) has shown that where forests were re-growing,  they took up large amounts of carbon partly because more carbon dioxide was available,  but also as a result of the younger age of the trees. This ‘youthful’ carbon uptake was not associated with tropical areas, but with regenerating forests of more temperate regions. Read more...