Bee:wild [https://beewild.rewild.org] is a new science-led, global campaign, which aims to help and save pollinators - particularly bees.  The woodlands blog has reported on the decline in many insect populations in recent times - referring to the ‘insect apocalypse’, the ‘windscreen test’,  and the ‘splatometer’. The causes for insect loss are many but critically important are : Habitat loss and fragmentation The extensive use of pesticides, herbicides & fungicides. These may be coupled with other issues such as climate change, and pollution from fertilisers into rivers and streams.  However, in recent times, we may now need “to add to the mix” - Wars and conflict.  These can result in changing patterns of agriculture so that the range of crops grown is reduced, which means there are less foraging opportunities for pollinators. The ubiquity of plastics. Specifically microplastics and nano plastics.  Microplastics come in part from larger plastic pieces that degrade into smaller pieces, but also from microbeads.  Microbeads are very small pieces of polyethylene plastic that are added to health and beauty products, such as certain skin cleansers and toothpastes. Now microplastics are to be found everywhere from the deep oceans, to Arctic snow and Antarctic ice. They are also found in the hives of honey bees.  Quite what their effect is on bees or indeed many other organisms (including us) is not yet clear. Artificial light.  Much of our world is illlluminated 24/7.  Towns and cities rarely experience total darkness, even the countryside is lit up by the lighting on roads and motorways.  This artificial light is not without effect.  Areas ‘bathed’ in light may Deter nocturnal moths from visiting flowers, reducing pollination and egg laying. Make the night flying moths ‘easier targets’ for predators (such as bats). Affect the feeding habits of moth caterpillars. Air and water pollution.  Both air and water are increasingly filled with a ‘cocktail’ of chemicals, some derived from the extensive use of pesticides (insecticides, herbicides, fungicides, some come from use of fertilisers).  Particulates released from car tyres and brake pads contribute to the ‘chemical smorgasbord’.  Whilst the effect of any given chemical may be sub-lethal, small, or non existent the combined effect of the mixture may be significant, even deadly.   Wild fires.  Add into this anthropogenic concoction mentioned above, the chemicals released from wild fires - such as those seen recently in Canada, Siberia, Australia and the United States.  These fires not only release a complex mixture of particulates and chemicals, they also destroy habitats for pollinators.  The sheer scale of these fires makes the recovery of ecosystems that much harder. Bee:wild [https://beewild.rewild.org] suggests a number of measures to help pollinators : A swifter move to electric cars to reduce levels of atmospheric pollution Production of crops with enhanced nectar and pollen production to benefit pollinators Creation of more flower-rich areas, for example, within solar farms Use of RNAi therapy to specifically target pests and not beneficial insects.  RNA interference is a technique that uses natural cellular processes to silence or reduce the expression of particular genes in a particular organism.  Thus, it might render a pest sterile. Introduction of measures to reduce the use of ‘our’ chemicals, used to enhance the growth of crop or animals. Such measures when coupled with the creation of urban rich flower gardens, rewilding and the protection of remaining areas of natural habitats will help pollinators, and insects in general.

Woodlands TV has just produced an interesting film about one of our native amphibians - the Great Crested Newt.  It is a species that has protected status through UK and European law.  It is an offence to kill, disturb or capture them, or their eggs.  Developers of building sites near ponds / breeding sites need to conduct surveys to see if newts are present in the area before work can start.  If there are newts present in an area, then appropriate mitigations must be put in place before work can start. The great crested newt, also known as the northern crested newt and the warty newt, is a species that is native to The UK.   It is also to be found parts of Europe and Western Siberia. Sadly, like many other invertebrates species, its numbers are in decline - falling in numbers from one million to 400000.   This dramatic decline is mainly due to loss of habitat.  Across the country, many ponds have been lost due to the advance of agriculture, particularly during the last century.  See the woodlands blog on Ghosts and Zombies. The newt is large, and females may be six inches or more in length.  The body is a deep brown in colour, though the underside (the belly) is yellow / orange with dark ‘blotches’.  In the breeding season, the males are particularly distinctive as they develop a crest on the back and tail. Interestingly, the newt spends most of the year on land, returning to water / breeding sites in the Spring.   In their aquatic phase, they will feed on insects, insect larvae, molluscs, tadpoles, even small newts.  On land, they will eat worms,  slugs and insects.  The newts may be eaten by birds (like herons), hedgehogs, badgers, foxes and grass snakes. The males offer a ritualised display to ‘court’ the females, and deposit a spermatophore, which is used to fertilise the female’s eggs.  A female may lay 200 to 400 eggs, often wrapped in pondweed (for protection from predators).  The eggs develop into larva and then transform into juveniles, known as efts. [embed]https://youtu.be/BSXyINFfPAs?si=UIrlCSXWlqVod1_s[/embed]

The plant genus Acer includes one hundred and thirty species.  The Japanese maple (Acer palmatum) has over a thousand cultivars, and includes many garden favourites - often small trees with delicate, finely divided leaves, which produce vivid colours in autumn; it is often used in making bonsai specimens.  However, Acer pseudoplatanus — the sycamore,  is by no means delicate. The sycamore is a large tree, often reaching a height of 35 to 40 metres, and is long lived with a life span that may extend for four hundred years.  It has large palmate leaves (see image) that turn yellow-brown colour at leaf fall.  These leaves can form a thick layer on the ground. If they fall in your garden, they can smother smaller, delicate plants.  The tree also produces large quantities of its winged seeds (double samaras).  After exposure to the cold of winter, the seeds may germinate and litter your garden with numerous seedlings. These can rapidly establish themselves as young saplings.  Because of its capacity for seed production and its effective dispersal mechanism it can become locally invasive. The sycamore is not a native tree and is not currently classified as an invasive species.  It was introduced into Britain, probably sometime around the 1500’s.  At present, it is classified by some as a neophyte - that is,  a plant that has naturalised but arrived on or after 1500 CE.  It arrived from Central Europe and, or many years, remained ‘unobtrusive’.  The sycamore is present in 90% of hectads in Britain; a hectad is a 10 km by 10 km square. Thus, the sycamore is found in more hectads than any native tree.    The sycamore can outcompete native species like oak and beech, and shade out understory plants.  On a more positive note, it does provide a habitat for various moth caterpillars, aphids, birds and lichens - though a sycamore does not support as many species as an oak. A veteran oak can ‘host’ many hundreds of plant and animal species. Sycamores can thrive in a variety of soils and climatic conditions, and are quite tolerant of wind and pollution.  They are now widespread in woodlands, hedgerows, parks and urban areas, making them a prominent feature of the British landscape.

Plantations are generally monocultures of economically important tree species, trees that are valued for their timber and rapid growth.  Compared to natural woodland, biodiversity is lower in monocultures. They are less resilient to extreme climatic events, attack by pests and/or disease and offer fewer ecosystems services.  Adding different trees into the mix of species can result in an increase in biomass (timber) production and resilience. Since the 1930’s, a ‘nursing mixture’ of Pines and Sitka Spruce has been used to establish Sitka forest in nutrient-poor soils (without the use of fertilisers or herbicides).  Quite how the pines benefited the growth of the Spruce was not known. One possible ‘mechanism’ is plant soil feedback [PSF], where plants change the nutrient make-up and/or the  bacterial and fungal community of the soil.  These changes then benefit the subsequent growth of seedlings / saplings.  Important in this respect are the fungi that can establish symbiotic / mycorrhizal associations with plant roots.  Ectomycorrhizae (ECM) exist mainly as an external coating on the roots, with some of the hyphae penetrating into the root tissue. Ectomycorrhizae are often associated with woody tree species, particularly conifers. There are a number of parts to a mycorrhizal association with trees: The Hartig net, this is the fungal hyphae that penetrate the roots of the tree, and make contact with the root cells, allowing for the exchange of carbon compounds, mineral nutrients, and water. The Mantle is the sheath of hyphae that covers the tree roots.  It is a more substantive structure than the Hartig net.  The fungal sheath probably offers some protection to the delicate root tips from pathogens and pests.   The Extra-radical hyphae. These grow out from the mantle into the soil. They may spread a significant distance from the actual roots, increasing the surface area for the absorption of water and minerals.  The Fruiting bodies.  These are the reproductive structures of the fungus and are visible above ground. Now some evidence is accumulating about how nursery mixtures / species have their effect.  Last year, researchers at Manchester University looked at the nursing effect of pine and silver birch on Sitka Spruce.   They collected soil from Cannock Chase, where these tree species co-existed.  The soil was sieved and some sand added and then placed in pots. Four groups of pots were created Pots with pine seedlings Pots with Spruce seedlings Pots with silver birch seedlings Pots with all three types of seedlings Pot Treatment Species grown in the conditioned soil Pine conditioned soil  Pine Spruce Birch Spruce conditioned soil  Pine Spruce Birch Birch conditioned soil  Pine  Spruce Birch Pine, Spruce & Birch conditioned soil  Pine Spruce Birch All the pots were placed in a greenhouse and the seedlings allowed to grow on for 34 weeks.  This allowed the growing seedlings to ‘condition’ the soil.  At the end of this time, the seedlings were removed and soil sieved and placed in fresh pots.   The four ‘types’ of ‘conditioned’ soil were then used to grow on newly germinated seeds of the three tree species.   One seedling was grown per pot, and the pots grown on for 24 weeks in the greenhouse again.   At the end of the 24 weeks, the seedlings from each pot were harvested and carefully examined.  For each, many features were recorded Root length Branching intensity Root tissue density Total root length dry weight /mass recorded Ectomycorrhizal colonisation (microscopic analysis) Specific leaf area VIII.Leaf dry matter Photosynthetic rate The soil was also subjected to detailed analysis (e.g : pH, nitrates, microbial enzymes etc). The results showed that  The Spruce seedlings grew best in the soil that had been previously ‘conditioned’ with Pine growing in it. The Spruce fared less well in the previously Spruce ‘conditioned’ soil The increased growth was associated with greater root colonisation by mycorrhizae. Longer term increased growth in the silver birch ‘conditioned’ soil might be associated with increased availability of soil nitrates It would seem that Pines facilitate the growth of the Spruce through the enhanced establishment of symbiotic, mycorrhizal connections.  These connections allow saplings to access vital mineral nutrients such as phosphate.  This study therefore goes some way to explaining the nursing effect of mixed species planting. Full details of this work may be accessed here :  https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2664.14848

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]