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Blog - Flora & Fauna

Losing woodlands and forests.

Losing woodlands and forests.

by The blog at woodlands.co.uk, 22 September, 2023, 4 comments

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.  
Sweet chestnut finger-jointing at InWood in Whitesmith,East Sussex.

Sweet chestnut finger-jointing at InWood in Whitesmith,East Sussex.

by Angus, 15 September, 2023, 1 comments

Chestnut coppice grows in abundance in the South East of England, especially in Kent and East Sussex. However it is quite small diameter, being harvested about every 15-25 years. The timber is very strong and resistant to rot. For some uses it is better than oak and unlike softwoods it does not need treating with chemicals. The problem is how to turn these relatively thin stems into useable pieces of timber and a small company, InWood, has found an answer. I was visiting The Woodland Centre to collect a batch of six-inch decking that the factory team had made for me, and they offered me a tour round the factory. Their answer is to glue it together using finger-joints which are actually stronger than the wood itself and you can use it for decking, cladding and even structural beams. My decking boards had machined-in grooves to stop it being slippery and there were other options for width such as their three-inch or four-inch boards. Peter Black, the factory manager, explained how they buy sweet chestnut planks and process them by sawing them to width, taking out the knots and any wood that is rotten or infested with woodworm. He says that there are also occasional shotgun pellets which need removing - many of the chestnut coppice woodlands in East Sussex are used for pheasant shoots. The sawing produces short pieces of the same width and thickness but the highlight for the visitor is seeing their German machine which automatically cuts a tooth-like pattern in each end and puts polyurethane glue on it. These sections are then pushed together to make long, virtually defect-free planks. The factory generates plenty of waste wood which burns well and burns hot - it is either used for heating the workshop or sold for firewood. Enviously I looked at the part of the workshop where they use a huge hydraulic press to make “Gluelam”, being laminated beams from planks. These bigger timber beams have lots of advantages over the alternative of using large sections of tree trunk: the wood is much more stable, is less likely to twist & warp, longer sections can be made and there is often less wastage. InWood’s front man is Alan Ellis whose phone number is 01825 872550, and he is happy to supply trade or retail. On their website (www.in-wood.co.uk) you can find some spectacular garden rooms which they make from laminated chestnut. We got our Sweet Chestnut decking from InWood because of the quality, and their sensible prices. This method of producing timber supports sustainable British Forestry as well as the coppicers.  Successive generations of coppice workers have used their skills since at least Roman times, when sweet chestnut was first introduced to southern England.
Birch trees and their products.

Birch trees and their products.

by The blog at woodlands.co.uk, 9 September, 2023, 1 comments

Hazels, alders, and hornbeams belong to the Birch family - the Betulaceae.  The white birch, silver birch has the scientific name Betula pendula.   The birch is the national tree of Finland. As trees go, it has a rather slender, delicate form, and may be seen swaying in the wind.  Its silvery / white bark develops blackened fissures with age.  Early in the year it forms flowers, the male flowers in the form of catkins.    The female flowers become a dark red colour after pollination, eventually forming small, wind dispersed, winged seeds. The male catkins release large quantities of pollen (before the leaves emerge).  This pollen is the dominant tree pollen in Northern Europe (in Spring).  It is often implicated in allergic responses such as rhinitis (runny nose / sneezing) and asthma.   Birch is a pioneer species, it can colonise open spaces, and disturbed ground quickly.  It grows fast and once established, it helps ‘protect’ or shelter slower growing species, like Oak.  It has a limited life span, perhaps a maximum circa 70 years and then gives way to longer lived species such as Oak and Beech.  The tree can provide a home or food for many species of insect, woodpeckers may nest in the trunks and other birds may feed on its seeds.   The tree is quite susceptible to the honey fungus, which is the name given to several species of the fungus Armillaria. The fungus attacks and kills the roots of a number of trees and shrubs. One symptom of honey fungus is a white fungal ‘layer’ between the bark and wood, often at ground level. Clumps of honey-coloured mushrooms sometimes appear briefly on infected stumps in Autumn. The birch tree has had many uses over the years, some dating back to the neolithic period.  It has been used to make perfumes, adhesives, and besom brooms. Bundles of birch twigs were used for corporal punishment, and the twigs may be available in saunas to stimulate blood flow in the skin!  The wood of the tree is used in furniture making, creating veneers and in wood turning.  However, it is the bark and sap that have attracted most interest and have many uses.  Slabs of the bark are used as roofing shingles, and strips of it were  / are used to make bast shoes and in handicrafts.  The bark has been used in tanning, and when heated a resin forms which can act as a waterproof glue.  In Spring, large quantities of sap rise up the stem(s) of the tree and this can be tapped. The sap is best collected in early Spring as, if collected later, it tends to have a somewhat bitter flavour.   Birch sap contains sugars, amino acids and minerals (e.g. manganese), it may be drunk fresh or fermented.  Bottled birch water is available online.   In recent times, attention has focused on wood pulp from birch.  It is a rich source of plant sterols and stanols.  Sterols and stanols are naturally occurring substances that have a chemical make up that is similar to cholesterol. They are found naturally in small quantities in vegetable oils, legumes, seeds, nuts, legumes, grains, and vegetables. Back in the 1950’s, they were found to lower cholesterol levels in the body, if eaten in large enough quantities. One called beta β-sitosterol was particularly effective in reducing the absorption of cholesterol from the intestines.  However, there was the problem of finding a rich enough source of these compounds.  This was ‘solved’ when it was found that wood pulp could yield the compounds in quantity.  Now margarine-like spreads, milks and yoghurts are available that contain β-sitosterol or similar stanols in sufficient quantity to effect a lowering of blood cholesterol levels.  β-sitosterol has also been to improve urinary flow in men with prostate enlargement.
Deer control - shoot to kill and cull, or are there other solutions?

Deer control – shoot to kill and cull, or are there other solutions?

by Angus, 30 August, 2023, 9 comments

Deer are eating out the bottom of our woodlands and wildlife is suffering.  Although the size of the national deer population is not known for sure it is probably at its highest for a thousand years. There may be as many as two million deer in the UK’s countryside. There are several types, such as the two native species, being the Red deer (Cervus elaphus) and the Roe deer (Capreolus capreolus) - which is the most populous of the larger deer being, perhaps, 500,000 animals. Then there are the ones the Normans introduced, the Fallow deer (Dama dama) with a population of at least 150,000. On top of that there are three species of deer which have been introduced from the Far East including the Sika deer (Cervus nippon).  The other two from China are very different - there are relatively small numbers of the Chinese Water deer (Hydropotes inermis), whereas there are probably hundreds of thousands of the small and mostly nocturnal Muntjac (Muntiacus reevesi). They are all hungry and they all love woodlands. Most people believe the deer population needs to be controlled, or even reduced in number, but the range of species makes that harder to do. If you reduce the population of one type of deer the others will expand their numbers. Culling, or shooting, is certainly helping but stalkers are usually only interested in the larger species with enough meat to make it worthwhile and this leaves the muntjac space to thrive. Here is a film we made of a Scottish deer stalker explaining her job and how her stalking helps with environmental management: [embed]https://www.youtube.com/watch?v=ISh2sN-Ljy8&ab_channel=WoodlandsTV[/embed] Megan: “99% of stalking is looking through the binoculars.” Other ways of controlling the deer population are fencing them out but that is expensive and unlikely to work in the large open areas of the British countryside such as the moors and the uplands. Another potential method of control is introducing predators such as lynx or other larger hunting species. This meets some resistance from the public and the unintended consequences are that the predators might well go after different species altogether and occasionally humans. Most work is going on with contraceptive solutions so that the birth rate is reduced and less killing or culling is needed. This is also being researched for controlling populations of wild boars and grey squirrels to keep their numbers in check. It means getting the drugs to the target species and usually to the females which is often done through their foodstuffs, using food hoppers which are designed to be only accessible to that species. Other approaches include sterilization through injections and the Deer Initiative partnership has done a lot of work on examining different methods of biological control of deer numbers: https://www.thedeerinitiative.co.uk/pdf/contraception-and-wild-deer-control.pdf It’s not easy.  Even if one of these methods works, it will require an enormous effort to cut deer populations particularly of the smaller and more evasive species such as the muntjac. What do you think should be done? Meanwhile , deer are dangerous to motor cars.  The British Deer society estimates that annually there are between 40,000 and 70,000 accidents involving deer and this leads to about 700 human injuries, and far more deer fatalities!. So, in short, an overpopulation of deer is a large and growing problem: they damage the flora in woodlands, they eat young saplings, they compete with other mammals for space, they eat farmers’ crops, they carry ticks and they cause road accidents. The challenge of controlling the deer population is very real.
New uses for 'waste' plant material.

New uses for ‘waste’ plant material.

by The blog at woodlands.co.uk, 18 August, 2023, 0 comments

Many trees emit a scent or fragrance.  They form volatile organic compounds (VOC’s), often oils.  Pine trees, for example, release pinenes. Such VOC’s contribute to the smell that you may experience as you walk through a woodland.  The VOCs contribute to the formation of aerosols.  An aerosol is a ‘mixture’ of very small particles (solid or liquid) in air; other examples of aerosols include mist, cigarette smoke, or even car exhaust fumes!  Recent research by the University of East Finland has showed that aerosols formed from VOCs can reduce the amount of solar radiation that reaches the earth’ surface, by scattering some of the radiation back into space.  [caption id="attachment_40200" align="aligncenter" width="532"] Felling in progress[/caption] Pine trees are often grown in vast numbers and periodically felled for timber and paper making.  One by-product of paper-making (by the Kraft process) is turpentine - formed by the condensation and collection of the volatile oils in the wood). The pinenes (α and β) are major constituents of turpentine.  ‘Turps’ is used as a solvent to thin oil-based paints, for producing varnishes and as a ‘raw material’ in the chemical industry.  α-Pinene was used to make toxaphene (an insecticide, now banned).  Pinene can also treated with acetic acid to make a perfume with a pine needle smell. Recently a team of scientists at the University of Bath have found a new use for the by-products of paper production.  Using pinene from turpentine, they have been able to make a number of pharmaceutical compounds that can then be made into the painkillers - paracetamol and ibuprofen.  They have also successfully made other chemicals from the plant based turpentine, including compounds that may be used to synthesise `beta-blockers (heart tablets) and salbutamol (used for asthma).   At present, many pharmaceuticals and other chemicals are ultimately derived from crude oil.  Hopefully, this research will ultimately lead to a more sustainable and ‘green’ approach to drug / pharmaceutical manufacture. Biochar is the black residue, consisting of carbon and ashes that remain when plant biomass is subject to pyrolysis - that is, very high temperatures with very little  or no oxygen present oxygen. The material that remains is largely elemental carbon.  The benefits of converting plant biomass into biochar is that the carbon is ‘locked up’, rather than being released by decay and decomposition into the atmosphere as carbon dioxide.  Its advocates claim that when added to soil, it improves soil structure and function, as well as being a form of carbon sequestration.. [caption id="attachment_40215" align="alignleft" width="300"] cocoa fruit[/caption] Various forms of biomass (woody debris, corn stalks) have been used to produce biochar, however, a novel method makes use of ‘discarded’ cocoa bean shells.  These are heated to a temperature in excess of 600oC, with no oxygen present.  This particular form of biochar is being produced in in Hamburg. The plant, which is one of the largest in Europe, receives a supply of used cocoa shells viably a network of grey pipes from a neighbouring chocolate factory.  Apart from its use as a fertiliser, it is possible that it might be used as an ingredient to create a ‘green’ (or more environmentally friendly) form of concrete. The sequestration of carbon is vital if we are to avoid the worst effects of climate change.  Global warming has triggered an increase in heatwaves, floods, droughts, and forest fires in recent years; June temperature data confirms it was the planet's hottest on record. Cocoa fruit : courtesy of Pixabay.
oak bark

‘Green chemistry’, tannins and leather

by The blog at woodlands.co.uk, 10 August, 2023, 0 comments

As society and industry have become increasingly aware of environmental damage, so there has been a growth in the search for sustainable practices, for example, switching from oil / coal based power generation to wind and solar power.  Now various industrial processes are looking to use natural and sustainable materials that cause less environmental damage, by making use of ‘green chemistry’. The leather industry (worldwide) make extensive use of chromium salts in the tanning process.  The object of the tanning process is to change animal hide into a leather that is resistant to microbial attack.  Chromium (III) sulphate is an effective and efficient tanning agent, forming compounds that interact with a protein (collagen) in the animal hide.  However, certain chromium (VI) compounds are hazardous if released into the environment.    Whilst chrome tanning is faster than vegetable tanning and produces a stretchable leather suitable for handbags and garments, research and thought are now being given to the greater use of vegetable tannins, using plant waste material.  Tannins are produced by many higher plants, indeed the bark of many trees, such as Oak, Chestnut, Acacia and Eucalyptus are rich sources of tannin. Tannins bind to the collagen in the hide so it becomes more resistant to bacterial attack. In a living tree, tannins serve to defend the tree against microbial attack and to dissuade herbivores (from insects to mammals) from eating the plant material - because of their bitter taste. Recent work has shown that waste material (bark) from Acacia nilotica (the Gum Arabic tree) and Eucalyptus globulus (Blue Gum tree) is rich in tannins and can be used commercially for tanning in the leather industry, and is a relatively eco-friendly process.  The process of reusing, recycling or composting waste materials and converting them into more useful products (materials, chemicals, fuels or sources of energy) is sometimes referred to as waste valorization. “Waste-to-energy” scenarios are becoming important as resources are depleted, and waste production and disposal  are increasingly problematic Eucalyptus image(above left) by sandid from Pixabay
Pine martens and red squirrels.

Pine martens and red squirrels.

by The blog at woodlands.co.uk, 2 August, 2023, 1 comments

The Gloucestershire Wildlife Trust has spearheaded an initiative to introduce Pine Martens to the Forest of Dean. Some 35 Pine Martens have been released into the forest, between 2019 and 2021.  They have produced litters each year, and there is now thought to a population of some 60 animals.  Pine Martens have two or three ‘kits’ (young) a year.   At one time, Pine Martens were common across the U.K. but the loss of their natural habitat (forest and woodlands) combined with hunting has reduced their presence to remote areas in the North and West. Now, they are a protected species; it is illegal to kill, disturb, sell or possess a pine marten.  Scotland’s population is estimated at 3700 adults.  In the Galloway Forest, the numbers of adults and young are being monitored with thermal imaging cameras.   Pine Martens enjoy a broad diet, ranging from small mammals, insects, eggs and wild fruits - eating that which is most abundant.  They will prey on grey squirrels, and there is the possibility that this may help red squirrels re-establish themselves in more southerly areas.  Forestry and Land (Scotland) have placed artificial pine marten dens in areas where there are red squirrels.  The boxes (with wood shavings to encourage nesting) are placed some 4 to 5 metres off the ground.  The Yorkshire Arboretum has just constructed a special enclosure and introduced a small population of red squirrels.  The enclosure is designed to keep Red Squirrels in and Grey Squirrels out. Two of the females have just produced four kits (young). The Gloucestershire Wildlife Trust is also involved in the Severn Treescapes project.  This is a scheme that involves significant tree planting to link the Wye Valley with the Wye Forest - to create a significant corridor of woodlands, hedgerows, orchards etc across the counties of Gloucestershire, Herefordshire and Worcestershire.   Woodlands TV has a video about the Pine Marten : [embed]https://youtu.be/20RS1M-U008[/embed]
Parts of a tree (3): the leaf

Parts of a tree (3): the leaf

by The blog at woodlands.co.uk, 21 July, 2023, 0 comments

Across the world there may be three trillion trees. A mature tree may have 200,000 leaves, so there are a lot of leaves in the world - not counting those on herbaceous plants, grasses and shrubs.  The broad structure of a leaf is outlined here in woodlands.co.uk Tree ID. The leaf is the site of photosynthesis, providing food for the tree, and oxygen for us.  As the leaf is rich in nutrients, it is a source of nutrition for many organisms - other than the tree.  Oak trees are said to support over 2000 species, ranging from mammals, birds, beetles, spiders, fungi - through leaf-based food chains.  Leaves also support many micro-organisms through the detrital food chain (the decomposition of leaves in the litter layer and the soil). We do not eat many tree leaves, though some do make their way into our diet.  For example, the evergreen shrub Camellia sinensis is widely grown in many parts of the world for the production of tea.  The young leaves can be picked in spring and dried to make tea.  Leaves of other plants are used in various herbal infusions or for flavouring such as bay, sage, oregano, thyme etc. The fact that leaves are attractive to so many herbivores means that trees (and other plants) take measures to protect themselves. Some measures are physical - such as spines, thorns, prickles etc.   But when is a thorn a thorn, rather than a spine or a prickle?  These terms are used casually and interchangeably.  Botanically speaking, they are all ‘spinose structures’ that is hard, rigid extensions or modifications of leaves, roots, or stems - all of which have sharp, stiff ends and all have the same role - to deter animals from eating the plant that bears them.  Plants that bear sharp structures that deter herbivory are termed spinescent.  There are differences between these various ‘structures’. thorns are derived from shoots (they may be branched or not, may or may not have leaves). The thorns of Hawthorn (Crataegus monogyna) can bear leaves. spines are derived from leaves (they may be formed from all of the leaf or just part of it and like thorns they have vascular tissue*) prickles are derived from the epidermis (the outer layer of cells of a stem, root or a leaf).   Prickles may be found almost anywhere on a plant and they do not have vascular tissue inside.  Wild lemon and lime trees (Genus: Citrus) have spines, which protect young plants and indeed the fruits. The defences on roses are often described as thorns, but they are prickles, as they do not have vascular tissue (xylem and phloem) inside them. Sometimes, the leaf epidermis forms smaller, ‘simpler’ physical barriers called trichomes.  These are outgrowths of epidermal tissue but generally consist of only a few cells which form a defence against small insects.  Equally, a thick,  waxy cuticle on a leaf may be something of a deterrent to smaller insects. Leaves sometimes form ‘teeth’ on the leaf margins and leaf apices.  A classic example of this is seen in Holly.  Holly leaves that develop at ground level are wavy, with large triangular ‘teeth’, bearing spines.   As the tree grows and holly can reach up to 80 feet,  the leaves become less spiny. The spines offer protection against grazing animals at the lower levels but are no longer needed when the trees reach a certain height. While physical defences such as spines, prickles and trichomes can deter various herbivores,  chemical defences may also be deployed.  Chemical defences can take different ‘forms’, such as  [caption id="attachment_28705" align="alignright" width="300"] Oozing latex - Euphorbia[/caption] tannins and phenolics. These create an bitter taste, they are complex polyphenols built from several phenolic molecules. Tannins are common in leaf tissues - particularly in the cells on the top surface of a leaf.  Scale leaves of buds are often particularly rich in tannins, reducing  the palatability or "tastiness" of the tissue thereby offering protection from herbivores.  Alkaloids are again usually bitter tasting compounds -, many of them derived from amino acids. Glycosides, as the name suggests, contain a sugar that is joined to another chemical, such as cyanide (as seen in bitter almonds (amygdalin). Another possibility is that leaves may emit chemicals (aka VOC’ volatile organic compounds, scents, aromas) that deter insect visitors, or if a leaf is under attack by a insect pest then a leaf may release a VOC to ‘warn’ nearby plants of the attack so that they produce chemicals that make the leaves distasteful. How long a leaf lives is incredibly variable, it may be eaten within days of its formation, it may last till autumn or it may last for years.  Many trees of temperate climes are deciduous, that is they shed their leaves come the shorter days of autumn.  The advantage of this is that the tree offers less resistance to the winds of winter, so is less likely to suffer physical damage (also true of snowfall).  The tree enters a state of dormancy until spring.  If in spring the tree produces flowers before the leaves (like Blackthorn) this  can facilitate wind dispersal of the pollen.  However, losing leaves each year means that their nutrients are either lost or have to be moved out and stored somewhere else.  Having longer lasting leaves means that nutrients are retained, which is a distinct advantage in a nutrient poor, harsh environment.  The longest lived leaves are found in a plant of the Namib Desert : Welwitschia.  This plant has two leaves throughout its life of some two thousand years.  The leaves may reach a length of 4 metres, the ends die or get worn away but the base generates new tissue.   Welwitschia is a type of Gymnosperm. Image (with thanks) by Nhelia from Pixabay  

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