Much has been said about the need to plant more trees to help to lock up carbon to help address climate change. So, it is particularly upsetting to see recently planted trees that have died during our dry summer and others weakened by the drought shedding their leaves early. This stress is in addition to the natural diseases with which they must contend as a matter of course.
Unfortunately, there are also diseases which, in our global economy, were imported from abroad accidentally. One such is the fungus that causes Ash Dieback. This was first identified in the UK in 2012 although there is evidence that it has been present in Europe for 30 years. It originates in Asia where it does little damage to the local ash species, but our ash - Fraxinus excelsior - has no natural defences to it.
Ash is a common species and makes up around 12% of Britain’s broadleaved woodland so its loss will have a significant impact on the landscape. It is estimated that up to 80% of the trees will be killed, although as we are still the early stages of the epidemic, it is hard to judge. Whatever the losses, there will be an impact on those species of wildlife which rely upon ash.
The disease can affect trees of all ages although young ones, and those growing in woodlands with high proportions of ash, seem to succumb most quickly. Trees growing in open locations such as streets or in hedgerows seem less susceptible and there appears to be a level of resistance in some trees which, although infected, survive.
Local woodland managers have already been clearing ash trees and doubtless we will continue to see this in the years ahead. Those of us old enough to recall the dramatic change to the landscape caused by Dutch Elm Disease in the 1970’s will fear the long-term effect of Ash Dieback but will draw some comfort from the way that other species started to fill the gaps left when the elms were gone. But we must hope that further diseases do not erupt to thwart plans to increase our woodland cover as part of the essential work to lock up more carbon.
by Andrew Graham
Dr. Peter Inness from the Meteorology Department of Reading University opened this fascinating talk, the last in our 2021/22 series of indoor meetings, with two images of the same patch of woodland near his Oxfordshire home taken two years apart to the day. In the first, the forest floor was carpeted with bluebells; in the second merely a green carpet with a few unopened bluebell buds visible. This was one of several illustrations he used to show how short term changes in weather can impact the natural world, as he sought to distinguish this variability from longer term trends.
In her recent PhD thesis a student at Reading had used data collected by volunteers across the British Isles (recorded on the Natures Calendar website managed by the Woodland Trust) to show that across the UK the mean first flower date for bluebells was 1st of May in 2013, but 8th April in 2017, fully three weeks earlier.
Dr Inness was able to explain this difference reflected short term climate impacts, rather than long term trends. Data for bluebell first-flowering dates and temperature records for January to April in successive years show that bluebell flowering dates respond to the weather and temperature conditions during March, February and January, as the plant stems emerge and the flower buds form, rather than during the flowering period itself. And, though invertebrates react rather more rapidly than plants, similar analyses for the first appearance of orange tip butterflies and for blue tits nesting reached similar conclusions.
In 2021, by contrast, hawthorn blossom appeared a whole month later than normal, reflecting an abnormally frosty April.
Looking at longer term trends and the impact of climate change, however, Dr Inness referred to the paper published recently by the Royal Society. This used records on 406 plant species, some dating from as far back as the 18th century, to show a marked shift that took place in the 1980s. Plants are now emerging on average a whole month earlier each year than seventy years ago.
He showed projections prepared by the Meteorological office to indicate that by 2050, in every other year we will experience summer temperatures similar to those we experienced in the very hot year of 2018. And, unless significant reductions in greenhouse gas emissions are achieved globally, these temperatures will be the annual norm by the end of the century. And he also showed projected rainfall maps clearly showing that our winters will be wetter and summers dryer, and warned that individual rainfall events will be 29% stronger. A new UK record for of 316mm rain in a 24 hour period, set as recently as 2009, was surpassed again only six years later in 2015 with a new record of 341mm. All of which suggests that nationally there are considerable tasks and costs ahead to prepare reservoirs and infrastructure to be able to cope.
From a wildlife perspective these climate trends are complex and deeply concerning. Dr Inness gave as examples the likely impact on the relatively shallow root systems of beech trees, less well adapted to cope with summer drought conditions than deeper rooted oaks. And the impact on populations of birds such as swallows whose northerly migrations are triggered by seasonal changes in daylight hours. They may arrive at European destinations too late to feed their young on invertebrates maturing earlier as a result of warmer Spring conditions.
Troubling as these issues are, the talk was hugely valuable and timely, providing us all with deeper insight into the impact weather and climate have on the natural world around us.
by Richard Budden
Mid-March into early April is the time of a “blackthorn winter”: a cold spell when the blackthorn is in bloom. This is perhaps because the combination of different strains of the species and the varied micro-climates of their growing locations mean that you can find blackthorn in flower somewhere for more than a month, during which it is likely that there will be at least one cold spell. Or perhaps it is that blackthorn scrub, with its clouds of flowers at their peak, look like the bushes have been covered with snow.
The small white flowers bloom on short stalks from buds along the spines and do so before the leaves appear. En masse, the bloom provides a welcome early source of nectar for insects. These pollinate the flowers, which then develop the distinctive blue-black sloes.
The tree grows naturally in scrub, copses, and woodland, and is commonly used to form a cattle-proof hedge. It favours sunny positions, and when left uncut can develop into considerable thickets, such as those in the Oddbrook valley. Mature trees can grow to a height of around 6–7m and live for up to 100 years. The deep brown bark is smooth, and twigs form distinctive, straight, side shoots which develop into thorns. Its trunk and stems form a dense wood which is good for burning and straight stems have been used for walking sticks, including the Irish shillelagh.
The foliage provides food for the caterpillars of several moths. The dense thickets provide sheltered nesting sites for birds, which then feast on these caterpillars, and later on the sloes.
The scarce brown hairstreak butterfly lays its eggs on blackthorn. This is the largest and brightest of the hairstreak butterflies, the female looking a gorgeous golden colour in flight. However, in common with other hairstreaks, it is quite a small butterfly and notoriously easy to overlook. They spend most of their adult lives perched in the tops of trees, out of sight, lapping honeydew from the leaves. If you are lucky, you might see a female when she descends to lay eggs, nearly always on blackthorn twigs in hedges or bits of sheltered scrub.
Our knowledge of the local distribution of this butterfly is improving all the time, due to the efforts of a small number of lepidopterists who tirelessly search suitable locations for these tiny eggs. Correctly identified, these are a reliable indicator of presence, although not necessarily breeding success, but gets around the difficulties of spotting an adult on the wing. The population appears to be spreading westwards from the area north-east of Salisbury. As eggs have been found in the vicinity of Grovely Wood, who knows, they may be present hereabouts without being recorded. Eyes peeled this August/September.
by Andrew Graham
Tree husbandry (Focus - February)
Members of the Society have been busy on practical projects recently. Before Christmas, in the parish meadow (behind the Nadder Centre) we planted nearly 150 trees. A number of trees and shrubs were planted in 2013 in the sheltered, south-western, bottom corner of the field. These are established now and are beginning to knit together. The new planting will augment these. Species planted included oak, birch, hawthorn, willow, dogwood, buckthorn, hornbeam, beech and crab apple. This diversity of species aims to make it as valuable for wildlife as well as interesting to look at. Most of the trees were relatively small, bare-rooted plants; planted correctly, these have the best chance of rapid establishment. Each is supported with a bamboo cane and spiral guard for protection while a woodchip mulch around the base will help to suppress weeds and retain moisture. We look forward to them bursting into leaf in the spring.
We also took the opportunity to weed amongst the young hedge line between the community orchard and the skatepark, again applying mulch to help their establishment.
An ongoing project is to lay the hedge which separates the parish meadow from orchard and skatepark. It will involve cutting away some of the existing growth to make the hedge line thicker and more vigorous in the long term. Laying prompts the existing shrubs in the hedge to send up new growth from the base while still growing from the remaining branches that have been laid. This prevents it getting gappy and top heavy and helps the hedge to develop the width which makes it most valuable to wildlife.
In the New Year members were hard at work coppicing in Oysters Coppice Wiltshire Wildlife Trust reserve near Semley. The society will also continue to organise coppicing in the community field in years to come. When coppicing, all the small trees and bushes are cut down to the ground over a defined area. This lets sunlight in and results in a flush of flowering plants for a few years until the cut stumps have regrown and shade returns. Some of the cut material is woven into dead hedges to protect the cut stumps – or stools as they are known – and later more is placed over the stools to prevent deer browsing. Many woodlands in Britain used to be managed as coppices but as the markets for the products that they produced – e.g., hurdles, thatching spars, fence rails and posts – declined so did coppicing, to the detriment of many woods’ wildlife.
by Andrew Graham
Congratulations to our chair, Peter Shallcross, Vice Chair of the Nadder Valley Farmer Group, on being short-listed for his disease-resistant elm project in the Conservation Project of the Year category of the 2022 Wiltshire Life Awards.
With 6,000 elm trees delivered nationally, Peter’s work over the last five years has made a significant contribution to the re-establishment of elm trees in our landscape and the conservation of species which rely on elms to thrive.
On a foggy day on 19th December, 25 willing volunteers with spades assembled in the Parish Meadow to plant 105 tree ‘whips’ (plants about 10” high) provided for free by the Woodland Trust to celebrate the Queen’s 70 years on the throne under the title ’The Queen’s Green Canopy’.
These consist of Crab Apple, Downy Birch, Goat Willow, Hazel and Hawthorn all of which will provide food and habitat for birds and insects in years to come. We also added self seeded trees from our gardens including Oak, Hornbeam, one Walnut, Beech and an Elm.
They have been planted to extend the existing copse at the bottom of the field below the skate park and Nadder Centre. This field has been given to the Parish Council on a long lease by the Fonthill Estate in compensation for the development of 90 houses on the other side of the Nadder Centre off Hindon Lane.
The baby trees have been protected with plastic guards which will be removed when the trees are established and the guards will be re-used. We also took the opportunity to do some maintenance work on other young trees which had been planted nearby in recent years.
Following the planting we all celebrated with mulled homemade plum wine and mince pies.
'Living with trees' ~ talk highlights
Robin Walter came to give our last talk of 2021 and we had a mix of people listening in the Victoria Hall and on Zoom. Robin shared photos from his new book “Living with trees” and his experience over the last 30 years of working for organisations dedicated to the conservation of trees and biodiversity.
A striking statistic was that 13% of the UK now has forest cover, compared to 40% average coverage across countries in Europe, with Finland being a stand-out at 70%. Of course, many countries in Europe cover large areas, with differing population densities and we are a small island with an historic industrial growth, but it strikes home how much we differ.
It is estimated that during the Roman period we were at 20% and our lowest point was after the First World War. The Forestry Commission was then set up in 1919 to address the parlous state of our 4.7% forest cover. A particular strategy after WW2 was to put in conifer plantations on old woodland sites so that they could hold both deciduous and spruce. For instance, at Kingsettle Wood near Shaftesbury, the pines can now gradually be removed to let in more light around the ash and the ground cover can expand.
Robin is a member of the Shaftesbury Tree Group which prepared The Town Tree Plan for 2020-25. It is active in educating the community about their glorious trees and created a map so that people can self-navigate or go on arranged walking tours. 60 people turned up for their inaugural walk! The striking Swedish whitebeam opposite the Abbey on Park Walk draws a lot of attention.
The government has set a target to reach 19% UK woodland cover by 2050. As Robin encouraged, it is up to whole communities to get together and talk about what they want and work with local landowners and councils to come to agreement on plans for the future. We were pleased to share the news that this Sunday, Debbie Carter was organising a group of volunteers to plant trees from the Woodland Trust, as part of Tisbury’s contribution to the ‘treebilee’, the Queen’s Green Canopy planting initiative created to mark Her Majesty’s Platinum Jubilee in 2022.
Tree planting this Sunday
Join us in the Tisbury Parish Meadow on Sunday 19th December at 10 am to help plant more than 100 trees received from the Woodland Trust (Downy Birch, Crab Apple, Hazel, Goat Willow and Hawthorn) together, with some disease-resistant elms.
The trees are merely whips at this stage, so the planting won’t take long, but you need to bring a spade with you.
Debbie and Andrew Carter have kindly offered to organise mulled plum wine and mince pies for anyone who comes to help. To give them an idea of how many to cater for, if you’re planning to come along, please let us know.
Holly and ivy (Focus - December)
As Christmas approaches, thoughts turn to decorating our homes for the festive season. Along with spruce trees and mistletoe, the plants I most associate with Christmas are the holly and the ivy. As well as providing decoration and being easy to identify, these common plants are important for our wildlife. Although hollies can live for up to 300 years, they rarely attain a large size. As they often grow in the understorey of woodlands, they can develop quite a straggly form as they seek whatever light they can reach. This slow growth makes the white wood very dense and good for a number of uses as well as the traditional walking stick.
Male and female flowers occur on different trees and are white with four petals. The flowers provide nectar and pollen for pollinating insects as well as a food source for holly blue butterfly caterpillars. These feed on the flowers of holly in spring while those emerging from the eggs laid in summer predominantly feed on ivy flowers.
Younger trees have spiky leaves, but as trees grow and age, the leaves are more likely to be smooth, especially in the upper branches. Unless a female plant has a male sufficiently close by, its flowers may not be pollinated and will not develop the bright scarlet berries that look so attractive against the glossy leaves. These berries are a vital source of food for birds in winter, and small mammals, such as wood mice and dormice and this helps to spread the seeds.
In the autumn and early winter, the fruits are hard and apparently unpalatable. But after being frozen or frosted several times, the fruits soften, and become milder in taste. At this point, favoured trees can be stripped by groups of thrushes which may noisily dispute possession of this food source.
Berries of ivy are also in demand as winter food for birds. They are black and are held in clusters on mature plants which are the only ones to produce the yellowish-green flowers. These bloom in small clusters in late summer when most other countryside flowers are over and so attract many bees and late flying butterflies such as the red admiral.
Ivy is a woody stemmed, self-clinging climber but can also grow as a trailing plant which roots at many points as it spreads. Ivies have enormous value to wildlife, providing all-important year-round shelter and nesting sites for huge numbers of creatures including birds, small mammals and invertebrates. Ivy has long been accused of strangling trees, but it does not harm the tree at all simply using it for support as it climbs towards the light.
As well as its association with Christmas the ivy has a number of symbolic connections. A wreath around the head was thought to prevent drunkenness and it was also thought to be a symbol of fidelity. Newly married couples used to be presented with an ivy wreath and an ivy frond remains a part of many a bridal bouquet today.
by Andrew Graham
This was the first of our 2021/22 series but sadly, we had to postpone the talk by Simon Smart of Black Sheep Countryside Management a consulting business for farmers across the downland landscape. Instead, our Chairman Peter Shallcross gave a talk about the work being done to restore disease-free elm trees to our countryside.
Most of you will know about the broad context of the topic: the decline of elm trees across the UK, ravaged by Dutch elm disease that has devastated huge areas of the countryside. If you’re unaware, or want to see an example of the disease progressing through a relatively young specimen, now is an ideal time. Dick Budden says that if you drive past his house (Chicksgrove Close, on the right hand side as you head out of Tisbury) you will see the elm in question growing out of the hedgerow just East of the entrance, with the leaves closest to the road prematurely withered while the rest of the tree still looks healthy – not merely an early sign of autumn’s approach. The tree may last another 12months or so, it seems, before it is completely dead and inevitably needs to be felled.
Peter described the origins and progress of the disease and its implications for wildlife. He talked about the initiative he's involved in to support the national programme for recovery and the re-population of our area that he is actively engaged in.
Photo: Avocets (Izzy Fry)
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