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  

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

President Trump is concerned that the Paris Climate Agreement will damage the U.S economy, cost jobs and offer a competitive advantage to Countries such as China and India.  In consequence, he has said that the United States will leave the Paris Climate Agreement and he has also ordered a review of ‘climate regulations’ legacy from the Obama administration.   The effect of these policies will be the release of greater quantities of carbon dioxide into the atmosphere - which will further exacerbate global warming and climate change. A New Zealand based organisation called Trump Forest wants to offset the extra CO2 emissions Read more...

The level of carbon dioxide in the atmosphere has been carefully monitored since the 1950’s (for example at Mauna Loa).  For much of recorded history and prior to the industrial revolution, the level of carbon dioxide was about 280 ppm.  However, its current level of 400 ppm represents a significant increase and is probably the highest value for some 800,000 years.  It has risen because of the burning of fossil fuels (coal, oil, peat etc.) - which release carbon dioxide.  This has contributed to global warming and the phenomenon of climate change. However, the rise in global temperature has not been quite as great as some calculations / predictions have proposed.  The “greening of the planet” (that is an increase in the number of trees and plants growing on the planet) was held to be responsible for this ‘reduction’ in anticipated temperatures. Read more...