In parts of the South West,  there is open moorland but some of its features betray its history.  Running across the landscape there are faint lines.  These lines are reaves, and they are a legacy of ancient farming and land management technique.  They may run for many miles across the countryside.  Reaves were essentially walls constructed from local stone and earth, and may date back to the Bronze Age.  They were used to divide up the land for farming or grazing by livestock.     Instead of creating hedgerows, walls were built probably due to the availability of the stone [granite / slate] and the harsher climate back then. The reaves allow archaeologists some insight into the nature of ancient societies, their land use and agriculture. The area of Dartmoor and its environs offer a well preserved historic landscape {eg. The Great Western Reave) that has not been heavily ‘over-written’ by subsequent development.   In medieval times or later, hedgerows were planted along or near many of the reaves. Whilst reaves were not originally built to support hedges they sometimes became the base for hedgerows enclosing parcels of land.  Some reaves align with more recent earth banks that are topped with shrubs of hazel and hawthorn.  Many reaves have been gradually colonised over the years by various plants and animals.  The structure / integrity of some reaves has been lost as their stones / slates were ‘redeployed’ to build new dry stone walls / boundaries in the 18th and 19th centuries. Another type of boundary is the cornditch, This a bank with vertical stones on the side. Sometimes there is also an actual ditch - created where the soil was excavated to build the bank.  Cornditches separated common grazing land [open moorland] from enclosed land / fields, essentially they stopped livestock entering cultivated areas.  They may be seen around Exmoor and Dartmoor. Reaves, hedgerows, hedges, banks all serve to separate up parcels of land, but they also add character to our countryside and serve to provide continuity across the landscape for many species (plant and animal) to move around. [caption id="attachment_42471" align="aligncenter" width="675"] Woodland bank with mature trees.[/caption] Many hedges have been lost due to the expansion of agriculture and increasing urbanisation, others have fallen into disrepair and some are flailed within an ’inch of their life’. [caption id="attachment_25527" align="aligncenter" width="600"] A flailed hedge[/caption] A sustainable way of managing tree lined hedge banks and a better alternative to the excessive cutting with heavy machinery is the traditional crafty of hedgelaying. This technique involves partially cutting stems of shrubs at a diagonal angle know as ‘pleaching’. Traditionally this would have been done with hand tools such as billhooks and axes with different regions of the Country having different designs of tool. Most species can be laid but most common are shrubs like hazel, hawthorn and blackthorn with some trees such as oak, beech or birch being allowed to grow on to become mature trees known as ‘standards’. Shrubs are laid by bending over and weaving them together holding with ‘stogs’ (see the woodlands blog on How to lay a hedge).  Skilled workers declined in the later part of the 20th Century but is now on the rise again thanks to changes in land management aims and some grant funding being available. Ideally a hedge should be laid within 10 years of planting and should be and then can be regularly trimmed. After 50 years the hedge can be laid again. Some hedges, such as beech lined stone-faced hedges are not traditionally laid but trees are pollarded (cut to a height above where regrowth can be eaten by livestock or deer) on a rotation to prevent trees becoming too heavy and blowing over in the wind. This is also a good supply of timber for logs. Hedges act as biological corridors, and provide unique habitats / niches.  Even dry stone walls offer opportunities for lichens and mosses, leading to the formation of biocrusts. Hedgerows are home to some 600 different plants, 1,500 insects, 65 birds and 20 mammal species – offering food and shelter, breeding and nesting sites. Many of these species have been identified as vulnerable. The loss of hedgerows, or a decline in their quality and care would effect the populations of these species.  Hedgerows also serve to capture carbon, absorbing CO2 from the atmosphere which helps fight global warming by storing carbon in complex organic compounds.  The roots of hedgerow shrubs and trees help reduce soil erosion, stabilising the soil and improving drainage, whilst the above ground stems and leaves reduce wind speed. In towns and cities, the leaves and aerial parts of hedges can ‘catch’ roadside pollutants and particulates. Thanks to Stuart Brooking, who is the woodlands manager for Devon.

Ash dieback began to spread in Europe in the 1990’s, reaching England in 2012.  It is a fungal disease that slowly but surely interrupts a tree’s ability to transport water.   The fungus responsible is Hymenoscyphus fraxineus, which is native to Asia.  The death / loss of mature trees not only reduces carbon dioxide uptake but also represents the loss of habitats for many species of insects and other animals.  The dead trees are also a hazard to people and property. Though many ash trees have now died after infection with this fungus, there is a small glimmer of hope on the horizon.  Some British ash trees are evolving a degree of resistance to the fungus.  Scientists from Kew and Queen Mary University of London have studied the genetic makeup of many mature european ash trees, and also hundreds of young saplings (at Marden Park in Surrey).   This revealed that resistance was more commonly found in young trees - a shift in the genetics of the trees within a generation.   The resistance to the fungus is NOT complete, but if these young trees make it to reproductive maturity then there will another chance for natural selection to ‘refine ‘ the process, through their offspring. However, it may be that a careful breeding program will be needed to establish true resistance / immunity. Interestingly, ash dieback has not reached America but the emerald ash borer has.  This insect is spreading and killing trees.  It is another example of the effects of the globalisation of world trade. Insects and other animals from across the world are being ‘mixed up’, moved from their native regions to new areas where they spread and cause damage as their predators and / or parasites have not travelled with them.   Trees and shrubs are now facing challenges and threats at an unprecedented rate. see also :  https://www.qmul.ac.uk/media/news/2025/science-and-engineering/se/british-ash-woodland-is-evolving-resistance-to-ash-dieback-.html  

JAcross Europe, the red squirrel is recognised as an endangered species.  The U.K populations are at risk due due to :- Habitat loss Competition with Grey Squirrels The effects of the squirrel pox virus The last two are a result of the introduction of the grey squirrel from America in the 19th century. Red squirrels are at home in all types of woodland and may even be seen in parks and gardens, but they 'like' mixed conifer forests best.  Scotland is home to many of the U.K's red squirrels. The number of squirrels is quite small – estimates of their number vary, perhaps there are less than 300,000* across the whole of Britain.   The status of red squirrel populations is a matter of considerable interest. [caption id="attachment_42416" align="alignleft" width="300"] Screenshot[/caption]  In 2014, it was noticed that some members of the Scottish red squirrel populations had abnormal growths on their ears, snout and limbs. Further investigations found that the squirrels were suffering from leprosy.  Leprosy  is a bacterial infection,  caused by two different species of mycobacteria: Mycobacterium leprae and Mycobacterium lepromatosis.   The two types of  bacteria have slightly different distributions in the squirrel populations of the U.K.  Whilst leprosy in squirrels was first reported in 2014,  it is likely that the disease has been around in squirrel populations for much, much longer, probably hundreds of years. Profesor Verena Schünemann,  Christian Urban et al have studied bacterial DNA extracted from human skeletons, dating from 400 CE to 1400 CE with deformities associated with leprosy.   They 'reconstructed' the genetic makeup of mediaeval forms of the bacterium.  Leprosy was not uncommon across Europe in mediaeval times - indeed up to the sixteenth century.   Disease, in its many forms , was a common part of life -  dysentery, diphtheria, typhoid, smallpox, and plague meant that life expectancy was limited. The last indigenous case of leprosy in the UK dates back to 1798.  In humans, leprosy causes muscle and nerve damage, which lead to deformity, blindness and disability.   Interestingly, research by Dr. Sarah Inskip has revealed that a pre-Norman skull [found in Hoxne in Suffolk] had a leprosy strain related to a form known to affect squirrels.  The same strain has also been found in medieval scandinavian skeletons.  It is possible that the  trade in squirrel pelts (and meat) could have contributed to the spread of the disease. Strong trade connections with Denmark and Sweden were in full flow in the medieval period.  Squirrel fur was also used as a lining for fine clothes and squirrels were kept as pets by some. The historical spread of leprosy is not fully understood.  The disease may have passed from squirrels to humans or vice versa in historical times.  Further study of the microbes that cause this disease (and that in squirrels) will help determine how the disease is acquired and transmitted.    The risk to human health is low. (Even so, good hygiene should be followed during any contact with wild animals). Professor Anna Meredith  (University of Edinburgh) is researching into this disease in squirrels.   Further reading / articles: https://www.newscientist.com/article/mg14819991-200-virus-blamed-on-invading-squirrels/ https://www.science.org/doi/10.1126/science.aah3783 https://www.theguardian.com/science/2017/oct/25/medieval-love-of-squirrel-fur-may-have-helped-spread-leprosy-study-reveals https://www.sciencedaily.com/releases/2017/10/171025103109.htm

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