About 3.5 billion or about 50 for each person. Yes, there’s some guesstimating but it can’t be far out.  Of course you can argue the toss about what counts as a tree and if you count tiny saplings you might get it up to 5 billion. Here’s the basis for this number - the UK is just over 60 million acres, of which about 14% is woodland.  That’s a big increase from 1900 when it was only about 5% and it’s far less than Europe where the average is almost 40%.  Anyway, suppose there are another 50% of trees outside woodlands - such as those in parks, field edges, urban trees, and on moorlands. That would be the equivalent of 12 million acres with tree cover.  How many trees per acre is a big question because large majestic trees can be so large that there can be only about 20 on each acre whereas for young saplings the number can be as high as 2,000. Conifers can be as many as 1,000 per acre but, as the tree crop is thinned, that reduces to the low hundreds. So a figure of just under 300 trees per acre looks typical and on 12 million acres that would give about 3.5 billion trees. They are not evenly distributed between different parts of the UK - for example Scotland has almost 20% tree cover and about 20M acres so of the UK’s trees, almost a third are in Scotland. That brings us onto what species these trees are. It turns out that in woodlands a quarter of the trees are Sitka spruce and half as much again are Scots pine.  Other conifers (Douglas fir, Norway spruce and Lodgepole pine) make up another 15% so over half our trees are conifers.  Of the deciduous trees English oak and Silver birch each make up another 10% or so with Beech and Hazel together making 15% of our trees. It’s a concentrated picture, with 87% of our trees being made up of the top 10 species. Whereas the British population is around a hundredth of the world’s population (1%) we are far less significant in tree terms. There are probably around 3 trillion trees worldwide so the UK has nearer to a thousandth of the trees in the world.  At least the UK is going in the right direction - whilst the world’s tree cover is reducing due to deforestation from fires, drought and agricultural expansion, the UK’s has been increasing, albeit gradually.  Since the start of the millennium we have probably increased tree cover by around 1%. [caption id="attachment_30295" align="aligncenter" width="650"] Chestnut coppice[/caption]

Should wolves be reintroduced into the landscape. Wolves are regarded as a keystone species in many areas . A keystone species is often a predator that prevents a particular herbivore from ‘eradicating’ a prominent plant species. Without the predators, the herbivore populations can explode, wiping out particular plants, and dramatically altering the character of the landscape / ecosystem.  The logic for the reintroduction of the wolf relates to bringing deer populations under control. Relatively few  wolves can have a significant effect of deer numbers.  Wolves not only kill deer, but keep them on the move restricting their browsing activities. Though the exact red deer population is unknown, estimates for Scotland suggest it is about 400,000.  What is clear is that the deer browsing is having a significant effect on the natural regeneration of woodland and forest throughout the region.  This lack of natural regeneration has contributed to the decline and loss of native woodland.  Indeed, Scotland has a low percentage of woodland cover (approximately 4%).  Natural regeneration does occur  where measures are in place to exclude deer, such as fencing;  Or where deer numbers are below four per square kilometre In these conditions, seedlings can then establish themselves and grow towards maturity. Researchers at the University of Leeds are suggesting that a population of 167 wolves across the Cairngorms, South-west Highlands. Central Highlands and North-west Highlands would be sufficient to reduce the red deer population to a level that would allow natural regeneration to occur.  This natural regeneration would mean more trees, more natural woodland, which in turn would lead to greater carbon sequestration, possibly removing one million tons of carbon from the atmosphere each year.   Their calculations, using a predator prey model for the wolves and deer, suggest each wolf would effectively result in an additional uptake of some 6000+ tonnes of carbon.  It is possible that wolf reintroduction would also lead to: Increased ecotourism A reduction in deer related road traffic accidents / collisions A reduction in Lyme disease (fewer ticks carrying the bacterium Borrelia burgdorferi.  A reduction in the cost associated with deer culls, deer management However, against these potential benefits, there are concerns of public acceptance of wolves in accessible spaces, the challenges they may bring to livestock farmers (especially sheep farmers), and the impact on the deer stalking community.   Whilst wolves were once common in the British landscape, they have not been present (except in wildlife parks) for centuries.  Wolves likely became extinct in England during the reign of Henry VII (1485 - 1509), though wolf bounties were still offered in some parts until the 19th century. In Scotland, at one time (during the reign of James VI of Scotland), wolves were considered such a threat to travellers that special houses / rest places (Spittals) were built along the travel routes for the nighttime protection of travellers.  The Spittal of Glenshee was one such refuge.  At Eddrachillis, the people resorted to burying their dead on an offshore island so that the graves were not disturbed by wolves.   “Thus every grave we dug The hungry wolf uptore And every morning the sod Was strewn with blood and gore Our mother earth had denied us rest On Ederachillis shore” From A book of Highland Minstrelsy (1846) Wolf populations likely peaked in the latter half of the sixteenth century, causing so much damage to cattle in Sutherland that in 1577 James VI ordered wolf hunts three times a year.  According to some accounts, the last wolf to be killed in Scotland was shot in Perthshire in 1680, though there are some claims that a few may have survived into the 18th century. The modelling of the effects of wolf re-introduction by Liverpool University is not the first study suggesting that Scotland’s woodlands and forest would benefit from the return of wolves. However, whether the idea will gain public acceptance or make significant headway remains to be seen.  

The tallest tree in England, a Douglas fir, is found on Exmoor.  The Douglas Fir was introduced into cultivation in 1827 by David Douglas.  Douglas was a gardener and botanist, who spent his early career in Scotland including time at the Botanical Gardens of Glasgow University.  He was recommended to the Royal Horticultural Society by William J Hooker, the first director of Kew Gardens.  Douglas made three trips to North America and was ultimately responsible for the introduction of many different species.  Some of the plants introduced during Victorian times include Sitka Spruce, Sugar Pine, Western White Pine, Ponderosa Pine, Lodgepole Pine, and Monterey Pine. These have transformed our landscape and the timber industry. Sadly, David Douglas died at an early age on an expedition to Hawaii, in suspicious circumstances. The Douglas Fir, despite its other common names, Douglas Spruce, Oregon Pine - is not a true fir , spruce, or pine. It is also not a hemlock. Its genus name is Pseudotsuga, means false hemlock.  The trees can grow to heights of nearly 100 metres, especially in their native coastal regions and may have a life span of 500 years. The Exmoor tree, planted 150 years ago, has reached a height of 63 metres (over 200 feet). However, as a relative youngster it still has some way to go — and it has competition. A recent survey* revealed there are a half million redwood trees in the UK.  Three species exist: the coastal redwood (Sequoia sempervirens ), the giant sequoia / redwood (Sequoiadendron giganteum), and the dawn redwood (Metasequoia glyptostroboides) They are among the largest trees on earth.  The coastal redwoods are the tallest of the three species.  The largest was measured to have a height of some 379 feet (115.5M).   Not only are these trees large but they are also impressive because of their longevity, living for a thousand years is not unusual.  Dendrochronology has aged one specimen at over 2500 years.   The coastal and the giant redwoods are found naturally on the pacific coast of California and Oregon.  Many of the UK redwoods, like the Douglas Fir, were introduced in Victorian times.  They were often planted on the estates of the wealthy and landed gentry. There are now probably more redwoods in the UK than in their native Pacific Coast range. Recent hot and dry weather has stressed the American trees, exposing them to intense wildfires. A recent study of some 5000 redwoods investigated how well the trees were ‘performing’ when compared to their American counterparts.  The tree were scanned with lasers  [a non invasive technique] to determine their height and volume (= biomass),  They were found to be growing just as well as those in the Sierra Nevada, this is probably due to our relatively mild but wet climate. The tallest redwood tree in the UK stands at 58 metres at Longleat, so somewhat behind the Douglas fir. However, whilst the Douglas Fir may have a life span of 500 years, a redwood can survive for 2000+ years, giving it time to catch up and overtake. * see  https://www.bbc.co.uk/news/science-environment-68518623 and https://royalsocietypublishing.org/doi/10.1098/rsos.230603

The colours found in the flowers and leaves of flowering plants [Angiosperms] can be ascribed to four major 'families' of pigments; the chlorophylls, carotenoids, flavonoids and betalains.  The chlorophylls are perhaps the most familiar as they are the main photosynthetic pigments, absorbing blue and red wavelengths of light. Chlorophyll in flowers is relatively unusual.  Indeed, green flowers are quite rare and often associated with wind pollination. Examples of green flowers include some species of Euphorbia, Hedera and Fritillaria. Green flowers, despite their less conspicuous nature, can still attract insect pollinators.  This is due partly to differences in light scattering and brightness (achromatic contrast) as revealed recently by researchers at the Univeristy of Seville. The carotenoids are pigments belonging to the isoprenoid group of chemicals.  They are commonly present in flowers, absorbing mainly blue wavelengths of light. They lend yellow, orange and very occasionally red colour to flowers.  Carotenoids are the petal pigments of many yellow-flowered plants of the Daisy (Asteraceae) and Bean (Fabaceae) families.  The flavonoids offer the most diverse range of pigments.  They are water-soluble polyphenols found in nearly all vascular plants. They are located in the vacuoles of cells.  Certain flavonoid groups, such as, the catechins, flavonols, flavones, isoflavones absorb in the ultraviolet region of the spectrum.  They are invisible to humans but can be recognised by many bees, flies, butterflies and most birds.  The anthocyanins, also part of the flavonoid group, absorb green light and reflect shades of purple, blue, and red. They occur in many tissues of flowering plants, including leaves, roots, and fruits (think blueberries and raspberries). The last group are the betalains. The name derives from the beetroot (Beta vulgaris).  They are nitrogen containing compounds, derived from the amino acid tyrosine. Betalains give rise to yellow to pink and red colours. The deep red-purple colour of beets, bougainvillea, amaranth, and many cacti comes from certain betalain pigments. Interestingly, plants that produce betalain pigments do not form anthocyanins.   Apart from these four major pigment types, other rarer pigments do exist. For example, the xanthones found in some species of irises.  Flower colours may be generated from one specific pigment or through the combination of different pigments. Thus, red petals may be result of red anthocyanins, or red betalains, red carotenoids, or even by the combination of orange carotenoids with purple anthocyanins.  The carotenoids and chlorophylls are stored in chromoplasts and chloroplasts of the petals respectively. Chromoplasts are membrane-bound, fluid filled  vesicles in which pigments may be stored.  Flavonoids and betalains, which are water-soluble compounds, are found in the vacuoles of cells. White petals result from the absence of coloured pigments and thus reflect all wavelengths of visible light, though UV light may be absorbed.  Most plants have a distinctive flower colour that is stable, despite the vagaries of climate.  Sometimes the flower colour can darken or even change.  For example, the colour may deepen over time or even alter.  The Purple Mistress [Moricandia arvensis, found in the mediterranean region] has lilac coloured flowers in spring, but these change to white flowers in the summer. [caption id="attachment_42267" align="aligncenter" width="675"] Iris[/caption]  

The grey—brown skeletal branches of trees are being cloaked in fresh green leaves as they unfurl from the buds that protected them through the winter months.  Their bright green colour is due to large amounts of chlorophyll.  The chlorophylls are pigments that can absorb many of the wavelengths of visible light, but not green.  Green wavelengths are reflected back into the environment, which is why our eyes perceive both young and mature leaves as green. Each leaf is made up of a variety of cells and tissues.  The top and bottom of the leaf are covered with a layer of cells  termed the epidermis.  It consists of many interlocking cells (rather like jigsaw pieces), sometimes called pavement cells.  Their function is to protect the underlying cells and also produce the waxy, waterproofing layer — the cuticle.   The lower epidermis is ‘pierced’ by the stomates.  These are the ‘breathing pores’ of the leaf, allowing the exchange of gases and water vapour.   The epidermis may also bear trichomes.  These are small ‘hair—like’ projections.  If there are many of them they can give the leaf a white or silvery appearance, helping to trap moist air near to the leaf surface to reduce water loss.  They  may also help to reflect sunlight, so that the leaf does not get too hot and on cold days can serve to protect the leaf from frost damage. Some trichomes have a protective function in that they may physically restrict the feeding of insects and other herbivores, and some contain a cocktail of toxic chemicals [e.g. nettles]. Under the upper epidermis and within the leaf, there is one or more layers of cells packed with chloroplasts - the palisade layer.  This is the principal site of photosynthesis within the leaf, where carbon dioxide is fixed into sugars and other vital nutrients.  The ‘by-product’ of photosynthesis is oxygen, which is not only essential for plant respiration but needed by the vast majority of animals on this planet.  It diffuses out of the leaf through the intercellular spaces of the next layer of the leaf - the mesophyll layer. The stomates allow gases in and out, but can close through the movement of their guard cells.  Stomates tend to close up at night or when the leaf experiences water stress.  Running throughout the body of the leaf is the xylem and phloem tissues, which conduct water, minerals and sugars etc around the plant. The sheer abundance of chlorophyll in many leaves masks the presence of other pigments, which only become visible when the leaf begins to senesce and the chlorophylls break down.  The leaf turns a yellow / orange colour due to the presence of carotenoid pigments.  Autumnal leaves can display a variety of colours due to other pigments such as the anthocyanins and xanthophylls.  Some leaves take protection very seriously   Curious fact : the leaf with the largest surface area is that of the Amazonian water lily, which can be 10 feet in diameter.

Leaves have three main parts:  The petiole, a stalk-like structure that connects the blade of the leaf to the stem of the plant. Some leaves don’t have petioles,  and are known as sessile leaves. The blade or lamina, usually the largest part of the leaf.  The edge of the leaf or the leaf margin may be described as entire, toothed, or lobed. The oak leaf, for example, is clearly lobed. The blade has many veins, forming a network, carrying water and nutrients, The base, the base is the region of the blade that attaches to the petiole. A leaf is said to be simple if its blade / lamina is undivided, if the ‘teeth’ or lobes do not reach down to the main vein of the leaf.  A compound leaf has several leaflets, which join up with a single leaf stalk or petiole. When identifying tree leaves, it is always important to look for the petiole,   as a single leaflet of a compound leaf can look like a simple leaf.  More details of leaf and tree structure can be found on this link on our website. Now for a challenge.  Can you or your children find a leaf (and name the tree it came from), that Has a serrated / toothed edge Has a lobed margin Has a smooth edge / margin Is a compound, palmate leaf Is a compound, pinnate leaf Is hairy Is not green, but red or a mixture of colours Is more or less circular Is fleshy / succulent Has spines on its edges Is needle shaped Has a thick (waxy?) cuticle or is very shiny Has net venation  is marcescent (might keep you hanging around) Go forage!

The terms ghosts and zombies often feature in films or TV programmes, but across the country the terms can also be applied to many hundreds, possibly thousands of lost and abandoned ponds.  Ponds have featured in the landscape for centuries or millennia.  Pingos -  formed in the depressions left after the last ice age. The middle of the C20th saw not only the destruction of many hedgerows, but the removal of many ponds.  This was particularly true in farming areas like East Anglia.  The strategy was to increase field size and allow access of complex machinery that was becoming available at that time; for example large combine harvesters.  Whilst the loss of the hedgerows and associated wildlife is well documented, the loss of ponds has not attracted so much attention.  Many hundred of ponds were filled in (often using the debris and material from the destruction of the hedgerows), to give a few more metres of arable land, and with machinery replacing horses the need for ‘watering holes’ diminished.  The infilled ponds are sometimes referred to as ghost ponds.  The location of these 'ponds' can sometimes be found  By studying old ordnance survey (or tithe) maps or  They may be visible using aerial photography / drones and picking up a different colour or shade of the crop growing in a field Noticing the accumulation of water after heavy rain in a slight depression, or a mist hovering over a particular part of a field A zombie pond is somewhat different.  It is a pond or very wet, marsh area which is shadowed by a tree canopy.  The pond has filled over many, many years with dead leaves, so that it has a deep layer of decomposing organic material.  The pond margins is generally overgrown, with willow and other vegetation where have begun to ‘invade’.  The pond is half dead / half alive, hence the term 'zombie'.  The area / water becomes anaerobic / anoxic, as the dead leaves rot and use up oxygen. Few life forms call it home - perhaps midge larvae or the occasional beetle. Indeed, such ponds may release not only carbon dioxide but also methane; the latter is a particularly potent greenhouse gas.  Zombie ponds may be found in woodlands, particularly where active management has fallen by the wayside. However, not all is lost, both ghost and zombie ponds can be resurrected.  In the case of ghost ponds, the infilling material / soil is dug out until the original base layer is reached.   This may be recognised by the dark, fine silt layer / sediment, which may contain the remnants of water snail shells.  Ideally, the excavation should mirror the original outline of the pond.  This may be determined in part by digging two trenches at right angles to each other. Details of the restoration procedure may be found here.   Freshly excavated ghost ponds should be left to fill with rainwater through the winter months, and left for plants and animal to colonise naturally.  Amazingly, several pond restoration projects have demonstrated that the original silt layer of the pond is a valuable seedbed of many aquatic and emergent plant species, even though the seeds may have lain there dormant for decades , possibly centuries.  The refreshed pond should also have a surrounding margin of land to separate it from any adjacent farmland activities - to prevent nutrient run off / pesticide application etc.  Further details of the restoration of lost ponds can be found at:- https://norfolkponds.org/ https://www.ucl.ac.uk/geography/news/2023/nov/bringing-ghost-ponds-back-life https://www.essexwt.org.uk/recovering-lost-ponds In the case of zombie ponds, there is a similar approach to restoration but it begins with the cutting back and / or removal of trees from around the pond to let light in.  Then the layers of rotting leaves / organic materials are scooped out, so that the original sediments of the pond are exposed.  The depth of the decomposing material may be quite significant.  However, with light pouring in and the rotting material removing the pond can soon develop a diverse community of plants (from the seedbed and pond 'visitors' e.g water-crowfoot, stoneworts, and animals).  The restoration / renewal of ponds in fields, meadows or woodlands makes a significant contribution to the biodiversity of an area. There is an excellent video about the restoration of ghost and zombie ponds on YouTube, featuring Professor Carl Sayer (UCL). Professor Sayer grew up in Norfolk, where many of these ‘hidden’ / lost ponds are to be found.  Visit the Razor Science Show “Bringing 'ghost' and 'zombie' ponds back from the dead”. [https://youtu.be/SYkbDdaUMBY?si=gd2jbfxk4iXLSFL5]  

While protecting dormouse habitats has become one of the big themes of British woodland conservation, it’s remarkable how little is actually known about these elusive creatures. At a recent dormouse education day led by Tom Fairfield, thirty enthusiastic conservationists fired off a barrage of questions—some of which even he struggled to answer. Why do we care about them? How many are there? Is their population stable or declining? However, “Dormouse Tom” was able to answer many other important questions about the hazel dormouse (Muscardinus avellanarius). For instance, they are widespread across southern and south-western England and in Wales (distribution map). He showed us dozens of photos of dormouse nests and demonstrated that hazel dormice aren’t restricted to hazel woodlands—they’ve been found in conifer plantations, and occasionally even on stony beaches. Tom believes the habitat protections put in place for the HS2 high-speed rail line don’t go far enough. The ecologists at Balfour Beatty only surveyed hazel woodlands along the planned route, ignoring other potential dormouse habitats. He’s learned a great deal about dormouse habits through two key methods: installing nest boxes and examining teeth marks left on discarded hazelnuts. If our roles were reversed, perhaps dormice would measure the human population by building us cosy hotels and searching for discarded apple cores. In late March and early April, dormice begin to emerge from hibernation, but they are nocturnal and difficult to spot—one of the ways they avoid predation. Tom acknowledges that some dormice are likely to be harmed during forestry operations, but there are steps foresters and builders can take to minimise the impact. His approach starts with surveys—though thorough ones can be costly. These, however, make it easier to implement core elements of a dormouse mitigation plan: avoiding key habitats, establishing buffer zones to protect woodland edges, and creating no-go areas during the breeding season (April to October). A forester from Natural Resources Wales attending the course pointed out a serious tension: if summer months are off-limits for forestry, operations must be pushed into winter, when wetter conditions and heavy machinery risk causing ruts and soil compaction. In parts of south-east England, the tiny hazel dormice are facing competition from the much larger edible dormouse (Glis glis), also known as the European fat dormouse. Introduced by the Romans and raised for food, these creatures were fattened in ceramic pots called gliraria and are still eaten today in countries like Slovenia and Croatia. Dormouse habitat protection seems set to remain a key part of British woodland conservation—partly because dormice are considered a “flagship species”: a charismatic and recognisable animal that represents deciduous woodland and helps rally public support for wider conservation efforts. Note there is a woodlands TV film about the hazel dormouse: [embed]https://youtu.be/COUh5ZluEew?si=1upUveV1FLoQRXV6[/embed]