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great tit

Food for thought?

by blogs at woodlands, 16 January, 2022, 0 comments

It is estimated that each year UK households spend some 250 million pounds on bird food.  This amounts to some 150,000 tonnes of suet pellets, fats balls, peanuts, sunflower seeds etc - on offer (in feeders of varying complexity*) in urban and sub-urban gardens.  These offerings are a marked contrast to the occasional kitchen scraps that were placed on home-made bird feeding tables some 50 years ago.  The question has recently been raised as to whether this is a good thing.  In 2019, research by the British Trust for Ornithology indicated that this provision of food can affect bird communities in the United Kingdom.   For example, species that rarely visited gardens in the past, have become common visitors. Now, researchers at Manchester Metropolitan University have suggested that these extensive offerings of food might be affecting the ecological balance between different species. Blue tits and great tits are regular feeders in gardens, and they appear to benefit from this provision.  Blue tits tend to be be quite dominant in terms of their interactions with other birds - whether quarrelling over food or nest sites.  Consequently, species like willow tits and marsh tits tend to ‘lose out’ in such altercations.  Certainly, willow tits miss out to blue tits in the competition for nesting sites.  Another species affected is the pied flycatcher.  This is a summer visitor, spending the winter in West Africa.  It, too, is in competition with great tits for nesting sites.  The provision of food for resident bird populations may tip the balance against summer migrants, like the flycatcher. The change in feeding patterns of some birds may of course be associated with the expansion of farming over the decades and the consequent loss of natural foods such as fruits, seeds, nuts and berries - from  hedgerow flowers and shrubs.  This may contribute to birds visiting gardens more often.  It may be that our desire to help garden wildlife needs more thought as to the type of ‘help’ that is offered.  This could involve allowing our roadside verges and gardens to be ‘wilder’, with less frequent moving of lawns / grassy areas, more ground cover, planting native trees (like crab apples, hawthorn), less weeding, allowing seeds and fruits  (eg. rose hips) to form, which would encourage insects / spiders Consequently more natural resources would be available to birds and only in harsh times would supplementary materials be needed.   NB : it is essential that feeders are regularly cleaned so that disease is kept to a minimum [e.g. Trichomonosis  caused by the protozoan parasite Trichomonas gallinae] . Remember later this month (28 - 30th January), there is the Big Garden Birdwatch, organised by the RSPB. For further information, click on the image below:-   A footnote : As a species, we have not always been kind to birds.  A recent paper from Tel Aviv University details how humans have been responsible for the extinction of hundreds of birds species (over the last 50,000 years).  They have listed some 469 species of birds that have been lost, though the true number is probably considerably higher.   Many of these extinctions occurred in a short time frame and  were due to either : The hunting of birds (and their eggs) for food or The killing of birds by animals (rats etc) that human expansion brought to islands / countries. Many of the extinct species shared a number of features : Most lived on islands Many were large or very large birds (e.g. the dodo on Mauritius - that provided humans with significant quantise of high quality protein. (A similar fate befell certain large lizards and turtles). Many of the birds were flightless and could not escape their hunters.  
Walking sticks and hazel nuts : Crith Wood

Walking sticks and hazel nuts : Crith Wood

by blogs at woodlands, 13 January, 2022, 1 comments

I purchased a small woodland in West Lothian in July 2020.  It is ex-forestry commission woodland of about 4.75 acres.  It had some open areas, gaps in its planting as a result of two gas-pipe easements through it. On one edge of the wood, there is a small river, the opposite boundary is a road. The parcel of woodland is one of several side-by-side blocks with common planting, mainly of larch, but with a fair number of hazel, oak, cherry, sycamore and a few stragglers of other species. I was attracted to this woodland because it had a mixture of well established trees, but also a good opportunity to plant out the unwooded areas (that might be a third of the area). Researching gas wayleaves, I found that the distance allowable for plantings from the actual pipeline varies with the species and size intended for the trees. There are simple restrictions on heavy plant digging along the route of the buried pipeline for obvious reasons.   My main objectives in buying a woodland were twofold  to have a nearby source of firewood (I live locally), and  to add to a legacy for my adult children - an inheritance of something a little different.  As an old saying goes – buy land, they’re not making any more of it! Initially I just visited the spot many times and got used to finding out what lives there, who goes there and what happens. Dog walkers use the area a lot, and trampled grass attest to their frequency. I’ve maintained their routes by trimming and mowing. but I also came across families of deer, and many different bird species. Despite there being over a hundred hazel trees, there seemed no evidence of squirrels; as yet I’ve never seen one. But what of these wayleaves? Wild meadowland is all very well, but these were more wild rushes land. Rushes abounded and the unplanted areas were almost 100% rushes. I researched a lot about these, and was keen to find a method of eradication that didn’t involve chemicals. I found it in an old fashioned scythe. Purchasing one and learning how to sharpen it, and use it to best effect, I found that after an initial foray with a sickle bar mower, the scythe was the best tool for keeping the rushes under control. Now after some eighteen months, I’ve probably got about a quarter of the rushes left and I am working to rid the wood of the rest. I don’t let them seed, nor get enough growth to keep going, consequently they’re dying. Planting Christmas trees would allow planting closer to the pipes / wayleaves. Off to a nursery in East Lothian I went and loaded up with a thousand Norway and Serbian Spruce seedlings. I’ve since bought another two hundred, so in total planted about 1200. Over 1100 survived the drought of summer 2021. And still I’ve found more space, so intend planting several hundred more, but will vary the varieties. I have also planted some willows from cuttings along the river bank. The hazels were an attraction. With more than hundred, perhaps even two hundred, it was obvious that they’d never been pruned, so I learned about that and set to work thinning them. This has led to making hazel walking sticks as a side hobby! I was looking forward to last autumn’s harvest, seeing the signs of the promised fruit early on and the developing nuts during the summer. Judging the right day to go and harvest them and expecting to fill a 200 litre drum,  off I went.   Imagine my surprise to find the ground all trampled and not a nut to be seen! This was the first sign of “squirrels”, ones that wear wellingtons!. I imagine someone has been harvesting them for years and how would they know that these now belonged to someone taking an interest in their land?  My grandchildren have loved going “to the forest”. And their grandfather likes the quiet, the flora, the fauna and the peace, even without nuts! The above account with thanks to Geoff Crowley
Promoting wildlife in gardens

Promoting wildlife in gardens

by blogs at woodlands, 7 January, 2022, 0 comments

Reports in the papers and electronic media have made us aware that many forms of wildlife are under threat.  This threat is wide ranging - from the destruction of tropical rain forests, coral reefs, the loss of species-rich meadows, the insect apocalypse - indeed where does this loss of plant and animal species end? One small positive observation amidst the doom and gloom is the findings of The Biodiversity in Urban Gardens project [BUGS] at the University of Sheffield.  The original study focused solely on Sheffield and finished in 2002, but  it was then extended to five cities across the U.K.    Professor K Gaston who led the study is now working at the University of Exeter.  The original study was important in that it revealed within Sheffield city, there was 33 km2 of wildlife habit was available within the city 360000 trees in the city limits 45000 nest boxes 25000 ponds and  50000 compost heaps Furthermore, there were in excess of a thousand plant species (flowering plants, ferns and conifers) and a diverse collection of invertebrates (bumblebees, hoverflies, beetles and spiders).  Whilst the diversity was in no way comparable to that of an ancient woodland (with veteran oak trees etc) or indeed of wetlands, it is significantly better than that found on farmland - particularly in those areas where the farming is intensive and characterised by monocultures (e.g. oil seed rape extending to the horizon).  Farmland now occupies some 70% of the landscape. Gardens, parks and urban areas are therefore an important resource for wildlife.  It is important as house building proceeds, on both brown and green field sites, that the associated gardens continue to provide ‘sanctuaries’ for wildlife, for example, by avoiding large areas of hard standing for cars (which also encourage  rain / water run off - which can overwhelm the drainage systems).  Professor Gaston has emphasised the importance of ‘dimensional complexity’ in gardens; that is a variety of trees, shrubs and plants of different shapes and sizes.  This provides a range of different niches / habitats for wildlife.  Of course,  in gardening to promote wildlife, there are the additional benefits (for householders) of physical and mental well-being.   Remember later this month, there is the Big Garden Birdwatch, organised by the RSPB. For further information, click on the image below:- [caption id="attachment_36525" align="aligncenter" width="670"] Ladybird 'stalking' aphids[/caption]
The sycamore : Acer pseudoplatanus.

The sycamore : Acer pseudoplatanus.

by blogs at woodlands, 30 December, 2021, 0 comments

Acer pseudoplatanus is known as the sycamore in the U.K, or the sycamore maple in the United States. It was first described in botanical terms by the Swedish naturalist Carl von Linné in 1753.  It is thought that the sycamore is an introduced species, as its native range is central Europe and Western Asia.  It probably arrived in this country in the Tudor period (circa 1500 CE).  That it has no old native names is perhaps indicative of its absence before Tudor times, (Some say it has been here longer and have suggested that it persisted in Scotland).  It was recorded in the wild in Kent in 1632.  The sycamore is probably best regarded as a neophyte.  A neophyte is a plant that is not native to a particular area / region and has been introduced in recent history. Whatever its background, the sycamore is now to be found spread across the country. Its spread is due in no small part to the capacity of a single tree to produce many hundreds, indeed thousands of seeds.  The seeds are ‘winged’.  The wing of each seed develops from an extension of the ovary wall.  Two seeds are joined together to form a structure termed a double samara - a 'helicopter-like' device.  The wings catch the wind and the fruit rotates as it falls from the tree. This slows the descent and enables seed dispersal over a greater distance.  The sycamore has been deliberately introduced in a number of countries as it is tolerant of air pollution, salt spray and wind and it readily invades disturbed ground (abandoned farmland, brownfield sites, roadsides etc).  It is now regarded as an invasive species in, for example, New Zealand.  The leaves of the sycamore are simple but large. Each leaf has five distinct lobes and five veins radiate from the base of the leaf into the lobes. The edge of the leaf is somewhat ‘ragged’ with rounded 'teeth'. The lower surface may bear some hairs. The leaves are arranged in opposite pairs around the twigs / stem. In Autumn,  heavy leaf fall can mean that the ground under a sycamore tree can be smothered with a significant layer of the leaves, consequently the diversity of the ground flora underneath the tree may suffer. In spring and summer, the leaves can support large populations of aphids. Evidence of aphids on the leaves may be seen in the form of honeydew; this is the sugary waste of their feeding.   It may fall onto lower leaves (and cars); it provides food for flies and other insects.  The aphids themselves are a food source for ladybirds.  Sometimes the leaves are covered with small, red 'blobs' / projections - these are galls caused by a mite (a small spider-like creature).  The female mite lays eggs in these structures. Sycamores can be coppiced, that is, cut down to a stump which will rapidly produce new growth - for poles etc.  The timber of the sycamore is close grained, white to cream in colour that turns ‘golden’ with age.  It can be used in making musical instruments (violins), furniture, wood flooring There are many other species in the genus Acer, for example, Acer platanoides - the Norway Maple, Acer campestre - the Field Maple, Acer palmatum - Japanese Maple, and Acer saccharum - the Sugar Maple.  All of these have a (diploid) chromosome number of 26. Interestingly, the sycamore has a chromosome number of 52 - the number of chromosomes per cell has doubled.  The sycamore is a polyploid. A couple of interesting historical points about sycamore ;  The Tolpuddle Martyrs' Tree is a very old sycamore. The tree was used as a meeting point (in 1833) for six local agricultural labourers to discuss low wages and their poor living / working conditions.  They are associated with the birth of the trade unionist movement.  The 'Tolpuddle Martyrs' (as they came to be known) were sentenced to seven years of penal labour in Australia and were transported to Botany Bay. Dule trees were used as gallows for public hangings and also used as gibbets for the display of the corpse after such hangings.  One such dule tree lies within the grounds of Leith Hall, near Huntly, Aberdeenshire. This tree is a sycamore. The strong timber of sycamore made it a favoured tree for this purpose. [caption id="attachment_36329" align="aligncenter" width="645"] emerging leaves[/caption]  
bee

Woodlands web updates. 12.

by blogs at woodlands, 27 December, 2021, 0 comments

More problems for bees. There is some evidence that power lines could be affecting honey bees as the lines emit an electro-magnetic field; these fields alter the bees ability to learn.  Lab experiments in which bees were exposed to electromagnetic fields similar to those under power lines showed that the bees were slower to learn to respond to a threat More likely to show aggressive behaviour Bee balls and hornets. The asian hornet is an invasive (non-native) species.  They arrived in Europe (France) in 2004.  DEFRA is trying to prevent them becoming established in the UK through the eradication of individuals and nests.  They are honeybee predators, capturing workers and feed them to their young. Back in the ‘home territory’ of the asian hornet, bees have a defence against attack.   Hundreds of worker bees quickly swarm into a balls around the hornet.   The bees then vibrate their wing muscles so quickly that they generate heat and the temperature inside the ball rises and roast the hornet alive with their body heat.  These “hot defensive bee balls” were  seen in Japanese honeybees (in 1995). The ball must form quickly before the hornet can send out pheromones to attract others of its kind. Sadly, this act of altruism by the workers comes at a cost.  Normally, workers live for several weeks but the bees that contribute to the ball die within 10 days. Unfortunately, our European honeybees do not possess such defensive strategies. Consequently, bee keepers are experimenting with various methods to deter the hornets, for example,  meshes, sticky patches and flashing lights on the hives. Warming soils ? Soils store vast amounts of carbon (in the form of humus / organic remains), more than the carbon locked up in trees.  Scientists from universities at Exeter and Stockholm have looked at data on some 9000 soil samples from around the world, and found that carbon storage declines with increasing temperature.  Coarse soils lose carbon faster than clay rich ones.
conifer woodland

Creating diverse woodlands and forests

by blogs at woodlands, 14 December, 2021, 2 comments

We know that forests are important to all life on the planet.  They have often been referred to as the ‘lungs of the earth’, a reference to the fact that they produce vast quantities of oxygen - which is essential for respiration for so many forms of life.  They also take up carbon dioxide and ‘fix’ it into complex organic molecules - from starches, to cellulose and lignin.  Thus, the carbon is locked away for months, years or even millennia.  The equatorial forests of Brazil and Sumatra are species rich, incredibly diverse, but deforestation and the expansion of agriculture are threats to many biodiverse, forested areas across the world. As so many forests and woodlands have been felled, there is now a movement to plant millions and millions of trees (across the world) in an attempt to mitigate climate change and in the UK to increase our percentage tree cover from a pretty low base.  Sadly, twentieth century forestry in the U.K was largely based on monocultures (for timber production). The trees planted were large stands or plantations of conifers - using Scots Pine, Larch and Spruce. These plantations not only lacked biodiversity, but were / are susceptible to wide scale pest infestation and extreme weather events.   Woodlands and forests that have a diverse range of tree species are not only healthier but show greater growth and carbon fixation. They are more resilient.  The diversity of trees ensures the each species accesses slightly different resources from the environment  - from soil minerals, water and light.  Diversity means that trees of the same species are less likely to be clustered together so pest and pathogen outbreaks are less common or less severe.  One area that has undergone an extensive and diverse planting regime is Norbury Park Estate (near Stafford).  Since 2009, over 100 different tree species have been planted, and the woodlands can now produce 1500 tonnes of new wood each year, and harvest 5000 tonnes of carbon dioxide from the air.  Not only can diverse woodlands / forests fix carbon, supply harvestable timber but they also offer areas for rest and relaxation. Whilst it is not possible to plant an 'instant' forest or woodland, it is possible to plant a range of tree and shrub species that will in time grow and mature to form a diverse and species-rich area.  As Charles Darwin said many years ago “more living beings can be supported on the same area the more they diverge in structure, habits, and constitution” [On the Origin of Species by means of Natural Selection, 1859] Managing woodlands for wildlife - see here.   N.B.  Opens a PDF.    
Masting

Masting

by blogs at woodlands, 10 December, 2021, 0 comments

‘The Fall’ in the eastern United States has been colourful and plentiful this year.  There have been bumper crops of acorns, maple seeds and pine cones.  It is a Mast Year.  The trees have produced enormous numbers of potential offspring. These seeds and fruits will have significant 'knock on effects' in the ecosystems for some years.   Beeches and oaks can release so many seeds that they significantly increase the organic content of the soil and its nutrient value.  This fuels fungal and microbial growth. Small mammals feast on the acorns / mast and their numbers increase.  They, in turn, are food for foxes, owls and other predators *.   Quite what drives a mast year has long been a cause of speculation.  Ideas have included  masting evolved to overwhelm seed predators (mice, squirrels etc.) and thus ensure that at least some seeds survive to germinate and grow on.  fluctuations in nutrient availability affect the trees and flower / fruit production environmental prediction - that masting occurs in those years when seeds are likely to have good weather for sprouting in the following Spring.   even sunspot activity has been invoked Recently, a database [MASTREE] was created of mast years (for Beech and Norway Spruce) that extends back centuries.  This has enabled scientists to explore the environmental prediction idea, that is, whether masting is correlated with climatic events and occurs when seeds are likely to have favourable weather for germination and growth in the Spring after their production. On comparing the data with climate records, they found masting events [in beeches] correlated with climate patterns associated with the NAO - North Atlantic Oscillation, i.e. changes in air pressure between Iceland (low) and the Azores (high).  A “positive” NAO phase favours both masting and subsequent seedling growth; that is warm wet winters promote seed production and dry springs favour seedling growth.  Quite how the trees turn such climatic events into ‘signals’ for masting is another matter. Not all are convinced however. Some argue that the resources used up in producing so many seeds / fruits mean that the trees are exhausted and it takes time for these resources to be replaced and for the tree to flower and fruit fully again.   Professor David Kelly has a somewhat different hypothesis related to weather .  He suggests greater warmth in the previous growing season(s) may be the trigger.  Quite how the trees ‘remember’ the warmth that they have experienced is not known; but one thought is that it is due to what is termed ‘epigenetic marking’.  It is possible that the DNA of the genes that affect flowering is changed by the warm temperatures.   The activation of particular genes can be altered by their DNA undergoing methylation - a process where methyl (-CH3) groups are added (or removed) from the DNA.  Further information on masting and climatic effects on trees - visit science.org * [Sadly, a Swiss study found good masting years were later associated with a rise in tick-borne disease.]  

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