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Blog - July 2022

Woodland web updates : 19

Woodland web updates : 19

by The blog at woodlands.co.uk, 29 July, 2022, 2 comments

Shade and stress. Shade (low light intensity) causes plants to elongate, reach up to the light to ‘outgrow’ the competition.  Such ‘elongated plants’ are said to exhibit etiolation.  However, there is a point when this strategy is counterproductive.  The plant simply cannot outgrow its taller neighbours, it is wasting resources and becoming weaker.  So plants in deep shade do not generally use this strategy.  Deep shade is detected by the phytochrome pigment system and ‘relayed' onto the plant’s circadian clock, the internal ‘daily time piece’.  This internal clock has various components and particular genes, some of which have an additional role in suppressing stem elongation (that would normally occur when shaded). Welsh woodlands and insect pollinators. A recent study across many different sites in Wales has revealed the habitats favoured by pollinators such as bees, overflies and butterflies.  The research found twice as many insects in broad leaved woodlands as compared to grassland areas.  They also found that farmlands without hedgerows had significantly fewer insects.  Both hedgerows and woodlands include trees such as oak and maple, which offer varied niches for pollinators.  They provide food (leaves) for larval stages, pollen and nectar for adults, plus egg laying sites and shelter. In Wales, there are plentiful grassland areas (mainly due to farming) with woodland only contributing 15% of land cover.  However, the Welsh Government aims to plant 180,000 hectares of new woodland by 2050.  New woodland will not only contribute to tackling climate change (through carbon sequestration) but will also do much to promote insect biodiversity. Sludge as fertiliser Sewage sludge is commonly spread across farmland as a form of fertiliser (throughout Europe).  Sewage sludge is the residual, semi-solid material that is the ‘by-product’ of sewage treatment of industrial and / or domestic wastewater. Sometimes, referred to as biosolids. It is a sustainable / renewable source of nutrients and reduces material going to landfill or incineration. The use of sludge has attracted attention as it can contain: Breakdown products of various medical / pharmaceutical that have been excreted / eliminated from us and / or animals, such as hormones, antibiotics, various drugs Heavy metals such as lead, cadmium, arsenic  Industrial chemicals / breakdown products PCB’s, dioxin Now, research at Cardiff University has shown that micro plastics in sludge are a problem; these are plastic particles less than 5 mm in size. It estimates that between 31,000 and 42,000 tonnes of micro-plastics are applied to European soils each year.  They are a threat to wildlife as they are easily ingested and can carry / contain toxic chemicals and may pass along the food chain.  The UK was shown to potentially have the highest level of microplastics in its soils, followed by Spain, Portugal and Germany.  
Rethinking the British countryside - more trees, fewer sheep?

Rethinking the British countryside – more trees, fewer sheep?

by Angus, 25 July, 2022, 0 comments

Perhaps it all started with a "No-shave November" (or "Movember") when men realised that they could go for a month without shaving and no one would mind.  It may also have been good for them as they thought more about men's health and they let nature take its course.  A few years later people started wondering about other habitual cutting, such as mowing their lawns religiously.  "No Mow May" was invented in 2019 by Plantlife with the idea that less cutting of grass would allow wildflowers to flourish.  The official reason for this concession to conservation was to allow the wild flowers and pollinators to thrive, but it may also have become popular because it allows maintenance teams to work a bit less hard during May.  In any event it's now so popular that about 36% of lawn owners now join in every year.  But it's spilled over well beyond just the month of May - many owners of lawns have questioned whether they really want so much short grass when alternatives are more interesting - and better for wildlife.  Even at the 2022 Chelsea Flower show there were several gardens demonstrating rewilding. So rethinking the scorched earth policy has now spread from men's chins to gardens and parks - but will it spread further?  What about our hillsides? For eighty years we have been intensively grazing these with sheep and cattle as if our lives depended on it - which maybe they did in 1942, when war-time convoys of food from the US were being torpedoed.  Even after grazing ceased to be a necessity sheep continued to dominate our hillsides with grants to sheep farmers making it profitable to use their four-legged lawnmowers at scale.  Farmers even grubbed out hedges in the 1970s, described by Oliver Rackham as the locust years, which made the countryside look even neater and tidier.  According to DEFRA there are currently about 32 million sheep in the UK, a third of them in Wales.  Land used for rough grazing and grassland makes up about 50% of the UK's total land area.  So for several generations now the UK has used half of its land to raise animals for eating, but times are changing rapidly.  Whereas those with meat-free diets used to be a tiny minority their numbers are growing rapidly - already at least 14% of the population is meat-free and for those of university age (18-23) the number is up to 25%, and rising. The combination of reduced demand for meat and increasing awareness that we can happily stop cutting the grass is prompting a rethink of how we use the British countryside.  Much of the grazing land is not suitable for growing agricultural crops so that leaves owners wondering what to do with their land.  Some are choosing rewilding in various ways but usually with far fewer grazing animals, longer grass and more wildflowers. [caption id="attachment_38426" align="aligncenter" width="600"] 'rewilding' of roadsides and verges[/caption] Others are planting trees and creating new woodlands.  Where the land is sold it's often to people who want to plant trees or simply to fence out sheep and allow "natural regeneration" allowing trees to self-select and grow on their own.  It's an appealing project for many families to take on 5 acres of grazing land, plant trees and convert it into a wood of their own. This re-evaluation of how grazing land is used is happening right across the world as plant based diets become more popular and there is potential to re-establish wilder habitats.  It's good for carbon emissions - not only because woodland fixes carbon but also because rewilding cuts the number of grazing animals releasing methane: belching by sheep and cattle creates a third of the total emissions of UK agriculture. Despite this, there may be resistance from the powerful National Union of Farmers which mostly represents bigger farmers and which promotes farming as an industry.  Farmers already complain about reductions in headcounts of livestock - since the peak in 1992, sheep headcount is down by about a third.  But it's also about the way the grant system is structured - millions of sheep only exist because of the farm payments, financed by taxpayers, and the condition of receiving these annual grants is that "unwanted" vegetation and wild plants have to be removed.  So even if the sheep don't chomp up biodiversity the farmers have to do it to get their grants. [caption id="attachment_21282" align="aligncenter" width="600"] Sheep grazing around solar array[/caption] Even beyond this suppression of diversity, sheep and cattle are damaging in many other ways such as compacting the soil which contributes to flooding and droughts. Meanwhile the number of men keeping their beards after no-shave November has increased and there are more gardens and parks with wild meadows so maybe the much bigger revolution in rural land use might follow. Governments have had it within their power for decades to reform the grant system but real change may be driven by people's behaviour - eating less meat and planting up their own woodlands.
How does rewilding help climate change?

How does rewilding help climate change?

by Honey Wyatt, 22 July, 2022, 0 comments

We are in the midst of a climate emergency: temperatures are rising, and in February 2022 the UN warned that more than 3 billion people are living in areas that are highly vulnerable to global warming, putting their lives at risk. Scientists suggest that rewilding could be one of the best climate solutions available to offset greenhouse gas emissions and to protect our lives and ecosystems. Rewilding involves restoring ecosystems and natural processes, and though at first it will require strict ecosystem management in order for it to be successful, the aim is that rewilding nature will allow it to then be able to ‘take care of itself’ and repair the damage made by humans. It’s estimated that restoring natural ecosystems could provide 37% of the greenhouse gas mitigation that’s needed for us to prevent the warming of the planet above 2 degrees celsius by 2030, so it should not be underestimated by national governments as a strategy to offset their emissions and restore the ecosystems of their countries. Ecosystem restoration Rewilding can restore ecosystems, allowing them to reach their full potential for fixing carbon, helping to offset greenhouse gas emissions through their own natural processes. Due to the fact that trees absorb carbon through the process of photosynthesis, it’s estimated that regenerating fully establishing forests will sequester 10 tonnes of CO2 per hectare from the atmosphere.  Meanwhile, restoring peatlands (which store more carbon than the world’s rainforests, but of which 80% have been damaged by draining, extracting, burning and overgrazing) will allow them to once again reach their full potential of sequestering carbon. Damaged peatlands in the UK release 23 million tonnes of carbon CO2 (or equivalent) per year, which is more than all of the UK’s oil refineries combined; restoring them will reduce this significant strain on the environment.   Restoring these ecosystems will also provide habitats for a large range of wildlife, which also play a crucial role in preventing climate change. The flora and fauna of an ecosystem are essential for its maintenance and conservation— they prevent catastrophic events like species’ extinction, flooding and wildfires. In fact, herbivores can have a massive effect on atmospheric carbon levels, so restoring their populations and allowing them to roam freely will mean they’re able to trample and compact soils and sediments, and increase the amount of carbon that’s absorbed and stored in plants, as well as impacting the natural growth of flora by redistributing seeds and their grazing. In the coming decades, as the effects of climate change worsen, reintroducing native plant and wildlife species will improve both the resiliency and carbon sequestering abilities of an area. It has also been shown that biodiverse environments are able to absorb more carbon, with each additional species introduced adding up to 6% in its total carbon stocks. Rewilding will benefit humans too of course, and not just in major ways (ie. protecting our livelihoods from the effects of climate change) but also by blurring the boundaries between the human and natural worlds, which will benefit our mental and physical health. There are also economic opportunities that can arise from rewilding, such as nature-based tourism.  Where is rewilding happening? There are many rewilding organisations across the world and in the UK, several of which have undertaken successful rewilding projects, restoring the carbon sequestering capabilities and increasing the numbers of species in different areas. Rewilding Europe have identified that after a decline in populations of several wildlife species, such as beavers, elks, whooper swans, and white-tailed eagles, they are finally increasing again. The Serengeti went from being a major source of carbon emissions to a sink after the wildebeest population were restored, and now sequesters between 1-8 million tons of carbon every year.  Rewilding has endless potential across the world, too: restoring forest elephants to their historic levels in the Congo basin could lead to it sequestering 85 million tons of carbon each year (the equivalent to France’s annual emissions) while rewilding and conserving the functional role of vertebrate and invertebrate species could supposedly magnify carbon uptake 1.5-12.5 times or more across terrestrial, freshwater and marine ecosystems.  The finance and politics of rewilding In the UK, Rewilding Britain has been calling upon the government to make a bolder ‘financial and political commitment to nature’s recovery,’ including developing policy for an ‘economy-wide carbon pricing mechanism linked to carbon emissions’ in order to raise money to fund rewilding projects. Though the Prime Minister has pledged to protect 30% of the UK’s land and sea by 2030 to allow it to recover and rewild, Rewilding Britain has suggested that there is not enough of an incentive for industries that contribute most to greenhouse gas emissions in the UK, such as the agricultural industry, and that the UK government have only attracted 2.5% of the funding that would be needed for the mitigation of greenhouse gases in this country. Instead, they propose a ‘polluter-pays’ approach whereby there is a mandatory price attributed to carbon emissions that the polluter must pay (they suggest £40 per tonne which would yield a maximum of £17.4 billion per year), which could then be reinvested into rewilding and conserving the natural environment. There would also be annual payments made to those who make efforts to offset carbon by restoring landscapes according to how much carbon (or equivalent) each landscape has the ability to sequester; woodlands would be £413 per hectare; salt marshes £322/ha; peat bogs and heathlands £292/ha; ponds and lakes £404/ha; offshore ecosystems £161/ha; and species-rich grasslands at £204/ha, with the payments being capped at 1,000 hectares per individual.  How to get involved in rewilding: Rewilding has the potential to make a significant contribution towards preventing the effects of climate change, but its full potential being reached relies on our international governments stepping up to the task of making sufficiently bold policy that incentivises farmers to restore landscapes, as well as businesses to pay the costs of their greenhouse gas emissions. The question is, how can the general public get involved in rewilding? There are lots of options available, whether that’s starting small by rewilding your garden by planting native wildflowers, to buying land with the intention of rewilding and conserving it, to volunteering for organisations such as Rewilding Europe, or writing to your local council to encourage them to leave roadside verges uncut. You might even consider providing funding for rewilding projects. Education about the rewilding benefits is also severely lacking, so raising awareness about how rewilding helps climate change is another way to get involved. No matter how we get involved, it will all contribute to the fight against climate change, so let’s get to it!
July Fungi Focus – Beefsteak Fungus

July Fungi Focus – Beefsteak Fungus

by Jasper Sharp, 18 July, 2022, 1 comments

Beefsteak Fungus. The very name seems to suggest a choice edible, something meaty, tasty and substantial. The Latin name, Fistulina hepatica, sounds more like a medical condition. The hepatica part means ‘liver’, for this is what the fruiting bodies look like: dark reddish-brown, wedge- or tongue-shaped and weeping large droplets of a crimson exudate that looks much like blood. Slice the relatively soft flesh of this large bracket and it has the marbled appearance of a steak. I think all but the most ardent forager would probably concur that the Beefsteak Fungus doesn’t taste remotely as good as it looks. Firm and juicy turns to wet and floppy in the pan, but if that isn’t enough of a deterrent, then the overpowering sour acetic taste will be. Like many woodland fungi, this species is best left where found to fulfil its primary function of distributing spores and providing food for more appreciative woodland denizens. The Beefsteak Fungus should be appearing in woodlands from any time now until mid-Autumn and is pretty easy to spot. Compared with other brackets, it is soft and pliable. It reaches about 30cm in diameter and 5cm in thickness and a thick stem can often be seen attaching it to its host. Its upper side ranges from flesh-pink when young to deep chestnut red-brown when mature. However, it is the yellowish underside, which also bleeds when cut, that provides the real clincher for identification. Rather than a surface pitted with pores, the Beefsteak Fungus has a thin layer of densely grouped tubes that hang down separately from one another rather than be embedded in the pore layer itself – this is where Fistulina (“little tubes”) part of the name comes from. These characteristics make it a unique fungus in Europe, where it is the only species in the Fistulinaceae family. You certainly won’t need a microscope to look at spores or suchlike to identify it, you’ll be relieved to hear. While it can be found on related trees like chestnut, the Beefsteak grows primarily on oak, usually fairly low down the trunk, and occasionally on stumps. More specifically, this brown-rotter favours older oaks, and with the UK boasting some 120 million oaks, with our 49,000 veteran or ancient oaks totalling more than all other European countries combined, we should feel particularly blessed. While the Beefsteak Fungus is a fairly common site in Britain, in several other countries it is considered rare. It is on the red list of legally protected species in Poland, to name one but one such example. There’s a potential problem even here in the UK, however. According to the Woodland Trust, Oaks can be considered “veteran” or “notable” when they reach the age of 150 years. After reaching 400 years, they are classed as ancient, and some can go on to live up to 1000 years. It is not just tree-huggers who should be up in arms by such incidents as the recent felling by Peterborough Council of a 600-year-old oak to avoid a potential insurance claim involving two houses on an estate built around the tree just 30 years before.  Ancient oaks support an astonishing biodiversity; not just lichens, mosses and a rich array of insects and other invertebrates, but birds, mammals and of course, fungi. According to the Standing Oak Tree Fungus Survey, of which more later, oaks support over 2,300 species (this is not including all the fungi and other microbes), of which 320 are endemic to oak and a further 229 only rarely found on any other trees. More can be read on oak biodiversity on the sites of the Woodland Trust, The Ancient Oaks of England and ActionOak. Ancient oaks support species that younger oaks can’t, and so Peterborough council’s announcement it would plant 100 new trees to mitigate the environmental impact caused by its destruction should be seen as the greenwash that it is. One of our big problems in the United Kingdom is that over the past century or so, we have been rather remiss in our protection of oaks, and come the inevitable loss of our oldest species, we are missing the new generations to replace them and therefore hosts for the numerous animal, plant and fungi species that depend upon them. In relation to fungi, the Beefsteak Fungus is safe for the moment, but there’s one other species in the UK that is considerably more at risk. The Oak Polypore (Buglossoporus quercinus), a large bracket found on ancient oaks in openly grown settings, is one of only four species on the Red List of legally protected species in UK.  It is believed to be present in “350 localities in Europe (incl. suspected unrecorded localities).” It is more prevalent here than the rest of Europe however, due to such relatively safe enclaves as the Windsor Crown Estate. But host and habitat lost are the main threats to the very rare fungus which, for such sad but inevitable reasons, I have been unable to find and photograph. This brings me back to the Standing Oak Tree Fungus Survey, spearheaded by Richard Wright as part of a PhD research project under the Action Oak initiative aimed at mapping the fungal diversity of Britain’s oaks of and assessing “their interactions, and their effects on the life of tree”, depending on such factors as their age and location. The project started in 2020 and is intended to run until 2023. There’s obviously a huge amount of data that needs collecting and crunching through for this, and this is where you, the Citizen Scientist, can play a role. The project openly encourages the involvement of “anyone who can tell a chicken-of-the-woods from a beefsteak” (easy – one is yellow; the other is red!), by reporting their finds on an app that can be downloaded from the project’s website here. There’s also the dedicated Standing Oak Tree Fungus Survey Facebook group that can be joined for more details and discussion. [caption id="attachment_38542" align="aligncenter" width="675"] Caption: Chicken or beef? The sulphur yellow layered brackets of the Chicken-of-the-Woods.[/caption] I emphasised the importance of more people taking an active interest in fungi in my post earlier this year.  : ‘Mycophilia and Recording the Fungal Diversity of the United Kingdom’.  Mycology can be a daunting and difficult subject, but this project provides a great starting point for those who wish to dig deeper. Englands oaks need you!
Community tree planting.

Community tree planting.

by Honey Wyatt, 15 July, 2022, 0 comments

There are many reasons to plant trees, but lots of us may not have the resources (experience, time, money or land) we need to get involved with tree planting, even if the desire is very much there.  Fear not!  Getting involved, a little or a lot, is easier than you might think. There are countless reputable tree planting organisations across the UK which provide opportunities and information to those who are keen to get involved, but may not know where to start.  It may be that you don’t have the space (or resources) to plant your own trees, or are a little tight on time but want to contribute where you can.  You may be considering buying land to plant a family woodland and are on the lookout for some guidance and experience beforehand.  Wherever you are coming from, volunteering for a local tree planting project or charity could be a good way to kickstart your tree planting journey.  It’s also a wonderful way to meet like-minded people and make new friends.  Community tree planting is both cost effective and efficient.  Planting up large areas of bare land is not a quick job. Although people are utilising innovative methods for planting trees (such as dropping saplings from helicopters in remote regions), tree planting is generally speaking a labour intensive activity.  Lots of man hours can mean hefty costs too.  But as the saying goes, many willing hands make light work, and so is the case with creating new woodland.  Volunteering bodies can take care of the organisational and logistical elements of a planting project, allowing individuals to step in and learn new skills, connect with their communities and make a positive contribution to our climate. Fifty members of a local community could comfortably achieve the same as a far smaller team of professional foresters.  Of course the spacings may not be quite as consistent, or the stakes quite as straight in the ground, but in the grand scheme of things this doesn’t matter!  The process of planting a young tree can be learned by anyone, of (almost) any age, from any background! Forest For Peterborough, a tree planting organisation in the UK, began with the aim of planting one tree per person in Peterborough, but has now planted over 100,000 trees to date and aims to plant 230,000 by 2030. They also offer education for young people so that they can learn how to make sustainable decisions and attempt to give people ‘opportunities to learn skills and connect with others.’ As well as the opportunities for socialising and meeting others, it is a great way to acquire new skills, confidence and a sense of fulfilment from engaging practically with the environment in which you live.  For those who may not have the time, will or resources to take on their own tree planting project, volunteering alongside others offers could be just the answer.  Getting outdoors and connected with nature is especially important since many of us have been working from home since the pandemic began, which has taken a toll on our essential need as humans to connect with other people and the natural world. [caption id="attachment_38532" align="alignleft" width="300"] redwood seedling[/caption] As well as the social aspect of tree planting, there are a host of benefits associated with increasing the numbers of trees and green in spaces in the communities in which we live. It has been shown that people who interact more with nature are more likely to have a higher sense of self-esteem and be more resilient to stress, whilst reducing other mental health issues such as depression and dementia. For children, contact with nature can positively impact their affective, cognitive and moral development. Children who have views of trees are also more likely to succeed in school, meaning tree planting has both individual and communal benefits. Communities with more well-maintained trees have an involved social capital, too, whilst also reducing ‘violence and aggression in households, and limiting criminal activity in neighborhoods.’ Imperial College found that having high-quality green spaces in an area leads to its residents having a greater attachment to and sense of pride in their community. These all contribute to the overall cohesion of a community, something that we all want for the areas we live in.   Whether you want to meet new people, get more exercise, contribute to your community or be a part of a lasting legacy to help combat a changing climate, finding local tree planting groups could be an excellent step in improving your health, as well as the health of your community and our planet.  There are a huge number of volunteering opportunities across the UK, far too many to list exhaustively here, but please see a selection below which may be of interest: Future Forests Networks: https://futureforestsnetwork.org/ Trees for Cities: https://www.treesforcities.org/get-involved Avon Needs Trees: https://www.avonneedstrees.org.uk/volunteering/ Forestry England: https://www.forestryengland.uk/volunteering Trees for Life:  https://treesforlife.org.uk/support/volunteer/ Trees for Shropshire:  https://treesforshropshire.org.uk/volunteer/ The Northern Forest: https://thenorthernforest.org.uk/get-involved/ The Heart of England Forest: https://heartofenglandforest.org/volunteer Parks for London: https://parksforlondon.org.uk/community-tree-planting/
The cuticle,  a protective barrier and ‘sun screen’.

The cuticle, a protective barrier and ‘sun screen’.

by Chris, 10 July, 2022, 0 comments

Plants make use of sunlight in order to photosynthesise and grow.  However, not all wavelengths of light are useful to plants.  The red and blue wavelengths of light are absorbed by chlorophyll and used in photosynthesis.  Green light is reflected, hence we see green leaves etc.  Another component of sunlight is ultra-violet light.  Whilst UV light can help our skin manufacture vitamin D, it can also do considerable damage to the skin and cause premature ageing and skin cancers.  As this is the case, we are advised to apply sun screen to exposed skin as it helps prevent sunburn, skin cancer and premature ageing.  But what of plants?  Do they also protect themselves from UV irradiation / damage?  Some new research suggests that the plant cuticle has a role. The cuticle is usually a thin layer made up of fatty/waxy material that covers the outside (the epidermis) of the plant.  Its ‘primary’ function is a barrier to the evaporation of water from the underlying tissues.  It also prevents tissues becoming waterlogged as its ‘repels’ rain / water (see headline image) and it also resists the entry of pathogens / micro-organisms.  In most flowering plants, the cuticle tends to be thicker on the top of the leaf (aka the adaxial surface) which is exposed directly to incoming light. Though the cuticle is usually a thin layer, in plants living in arid environments, it can be quite thick to limit water loss. Since the waxy cuticle repels water (i.e. is hydrophobic), the adhesion of water to the cuticular surface is minimised so globules form.  Some plant leaves (eg. Nasturtiums and the Lotus) exhibit ultrahydrophobicity, so that they essentially become self-cleaning surfaces. Now, the rôle of the cuticle in protecting plants from UV damage is unravelling.  Research at the University of Malaga has shown the cuticle can quench UV light.  It does this though the phenolic compounds present in the cuticle.  Phenolics are rings of carbon atoms, with hydroxyl (OH) groups attached.  Examples are the cinnamic acids [e.g. p-coumaric acid]. When these molecules absorb UV light, they change shape momentarily.  On changing back to the original state, the absorbed energy is released but at a longer wavelength, which is far less damaging than UV light. As these molecules do not react this way to red and blue light, the red and blue wavelengths can pass into the leaf to be used in photosynthesis. [caption id="attachment_38494" align="aligncenter" width="700"] The leaves of some plants have quite amazing surfaces, some are hairy whilst others have protective spines.,[/caption]
rot inside trunk

Ultrasound scans for trees – how to measure rot in the trunk

by Angus, 6 July, 2022, 0 comments

Even if a tree looks healthy the trunk may be rotten to the core.  One day it will be vertical the next day suddenly horizontal and in falling it can kill people, crush cars and damage buildings.  So, knowing what's under the bark is really important.  Suspicion of rot might have been raised from a fungus, or a die-back of branches, or a hollow sound when the trunk is trapped.  In any event, it's one thing to suspect rot and another to know the exact extent of it and where it is, which is the problem that can be solved by a Sonic Tomograph, which is an ultrasound scan. The tree surveyor puts a series of nails into the tree in a ring around the outside - often about 40-90 cm above the ground - and he/she wires these up to the ultrasound.  The kit illustrated here is a PiCUS (named after the Latin for Woodpecker) made in Germany which can be carried in a small bag the size of a briefcase. For a horse-chestnut tree like this one with a diameter of about 2.5 metres the arboricultural surveyor needed ten nails.  Once these have been banged in through the bark, and the PiCUS wires attached to each one the surveyor then taps each one lightly with a special hammer and this sends sound waves through the trunk to each of the sensors attached to the other nails.  The PiCUS device will measure whether these sound waves are going through good timber, rotten timber or voids.  This then allows the computer to create a detailed and colourful picture of the trunk showing how much rot there is and where it's located in the cross-section. In our case the horse-chestnut tree, which looks fairly healthy, turns out to have rot covering 41% of the cross section.  Anything above 30% suggests the tree is unsafe and in this particular case the tree is overhanging a busy road and pavement so the whole tree will almost certainly need to be dismantled and replaced. Many of the sonic Tomograph surveys are done for local authorities and institutions to protect the public by reducing the risk of falling trees. A single tree only takes about 20 minutes to survey so there is good economy in doing several on each visit.  One official I spoke to said, "one reason we do these PiCUS surveys is so that neighbours and local people can see why we are cutting down trees that they love." The contractor here is Kim Gifford who is based in South East England and is on 07831 488456.  He's a very experienced surveyor and also spotted another rotten tree on his visit - a Tulip tree - which he surveyed and showed that it too needs to be cut down, sadly.  An alternative, in some circumstances is to take off the whole branch structure and turn the tree into a monolith, though in most circumstances it's better to eliminate the tree and start again with planting a new tree.
woodland web updates 18

woodland web updates 18

by The blog at woodlands.co.uk, 1 July, 2022, 0 comments

Mites and bees. Varroa destructor also known as the Varroa mite is a small, external parasite of the honey bee : Apis mellifera. It is a mite. Mites are small members of the arachnids (8 legged arthropods).  The mite(s) attaches to the body of the bee and feeds upon its fat bodies; this weakens the bee. The mite also feeds on bee larvae. Not only that but the mite can act as a vector (‘distributor’) for five different viruses that also weaken the bees.  The varroa mite originally was to be found in Asia, and was parasitic on the Asian honeybee, Apis cerana.  Sadly, it has now spread to many countries and is responsible for significant infestations of European honeybee hives.  Over time, the mites have become increasingly resistant to chemical treatments. Now a program / study by the Universities of Exeter and Louisiana has been selectively breeding bees that identify and remove mites from their colonies [ie. showing hygienic behaviours].  They do this by removing infected larvae from the colony.  This is sometimes referred to as varroa sensitive hygiene.  Such colonies showed significant reduction in mite numbers and were more than twice as likely to survive winter as compared the ‘standard’ honey bees. The colonies also had reduced levels of three honey bee viruses The study looked at bee colonies across three American states, including California.  In the States, beekeepers move thousands of bee colonies to provide pollination services for many different fruit crops (e.g. almonds) in the Spring, thus winter survival of the colonies is vital. Historic rainfall records. was launched in March 2020 (during the 'first stay at home' / lockdown).  Members of the public were asked to help record digitally the information on pre-1960 weather sheets.  The Met Office archives had some 65000 sheets that contained the ‘scribbled records’ of thousands of weather stations/ weather recorders across the country.    Many of these sheets were the records of amateurs dating back decades, many before the foundation of the Met Office in 1854. One such 'recorder' was Lady Bayning of Norfolk, she was an early rainfall observer who took readings from 1835 to 1887.  Deciphering the idiosyncratic handwriting could not be done by character recognition software. However, the volunteers rose to the challenge and the task was completed in some 16 days. As a result, now the Met office has: Rainfall readings stretching back to 1836 Data from an increased number of rain guages  Identified the driest year on record - 1855 Identified the driest month on record February 1932 Identified the wettest month on record October 1903 Note : [The Met Office was founded by Robert Fitzroy, the captain of HMS Beagle, that carried Charles Darwin on his epic voyage around the globe. Fitzroy essentially established the science of weather forecasting] Trees on the move ? We know that trees can ‘move’.   They did so at the end of the last Ice Age (some 12,000 years ago).  As the glaciers retreated so trees started to return to the newly exposed soils as the temperature warmed.  The discovery of the remains of acorns in archaeological digs, and analyses of fossil pollen records indicates that even oaks colonised areas of the UK at the rate of nearly a kilometre a year.   Similarly, Norwegian Spruce colonised areas around the Baltic Sea and the boreal forests grew and expanded - long before humans arrived there.   Now we have warming temperatures as we have moved into the Anthropocene.  In order to survive changes conditions, plants, like us, have to move. So, like after the ice Age, plants and trees are on the move.  Scientists in California have calculated that as a result of global temperature changes, plants need to move northwards (or upwards) at the rate of 400+ metres a year.  In the eastern parts of the United States, it has been estimated that trees were shifted north and westward at a rate of 10 / 15 km per decade.  The conifers going north. Whilst oaks and birches going west.  In Scandinavia, which has experienced significant aspects of global warming, birch saplings are now found higher up mountains, gaining 500 metres in elevation within two decades.  Pines, spruces and willows are also growing at higher altitudes than previously.  Similar colonisations of  hillsides and ‘bare valleys” are seen in Alaska of alder, willow and dwarf birch. Further information here [caption id="attachment_38737" align="aligncenter" width="700"] Busy bee[/caption]