Woodlands.co.uk

Blog - June 2024

The bee 'microbiome'.

The bee ‘microbiome’.

by The blog at woodlands.co.uk, 29 June, 2024, 0 comments

The honey bee, Apis mellifera, stores food in the form of bee bread. Bee bread is formed through the fermentation of a mixture of pollen, nectar and bee saliva.   It is 'inoculated' with a range of bacteria and yeasts that ferment the material after storage in the comb cells of a hive.  Bee bread is the chief protein resource for bees, particularly for the feeding of larvae [and adults].  As it is a nutrient-rich material, it ‘supports’ various microorganisms, despite its acidic nature and low water content. Bee bread is also coated with propolis.  Propolis (sometimes called ‘bee glue’) is a resinous substance collected by bees from tree bark and leaf buds. This resin is ‘chewed’, mixed with salivary enzymes and the partially digested material is mixed with beeswax.  It is an antimicrobial substance.  It is used by bees to seal holes in their honeycombs and help in the construction of the hive. The very nature of bee bread and the coating of propolis create a ‘challenging environment’ for microbes to grow and survive.   However, despite the ‘unwelcoming’ nature of bee bread, several species of fungi and bacteria form a microbiome within a hive, and are thought to play an rôle in the life of the bees. Recent studies have revealed that the fungus Aspergillus flavus is well adapted to survive in bee colonies.  A strain extracted from a hive was found not only tolerate low pH (which other strains of the fungus could not cope with) but could also deal with the low water content of bee bread, and with the propolis - which is thought to have anti-fungal properties.  Further work demonstrated that this strain of the fungus had mutations that allowed it to develop within the ‘bee bread environment’.  That this fungus can live with the bees suggests that there might be some form of mutual benefit to both fungus and bee, but the relationship (if there is one) is not as yet understood. Full details of this study can be found here  
Deer in woodlands

Deer in woodlands

by The blog at woodlands.co.uk, 22 June, 2024, 3 comments

Woodland covers some 1,000 hectares of the Ashdown Forest, that is roughly 40% of its area. Much of the woodland is relatively young. However, the forest’s capacity for regeneration / renewal is being damaged by overgrazing.  Local deer populations have grown and now represent a problem. Deer browse / graze on vegetation, shoots, flower buds and foliage are stripped off plants.  Young saplings are damaged and bark is eaten, especially when food is scarce.  Consequently, tree and shrub regeneration is limited.  Other species are affected by the feeding of the deer, either through loss of niches or food.  Among those at risk are small mammals and certain butterfly species. [caption id="attachment_34368" align="aligncenter" width="650"] deer damage[/caption] Damage is found in woodlands in many parts of the country, as deer populations have increased in recent times. In the 1970s, the deer population was estimated to be around 450,000 as compared to today’s estimates of over 2 million.  The National Forest Inventory highlighted that "40 percent of British forests have ‘unfavourable’ levels herbivore damage, which limits the survival of young trees and threatens biodiversity".  Apart from deer damage, there is damage by the grey squirrel populations. Deer browsing can : Prevent natural regeneration Affect biodiversity Affect woodland resilience Reduce food availability to the herd which can lead to starvation / loss of condition Deer are also hosts to ticks.  The ticks may be infected with Borrelia burgdorferi  bacteria and transmit them to humans, resulting in Lyme disease. Deer  also contribute to collisions with motor vehicles; more than 450 deer were hit by vehicles on Hampshire roads last year .  In Scotland,  government agency figures indicate that deer vehicle collisions  [DVCs] have almost doubled between 2008 and 2020.   Sadly, people are injured or killed in DVCs, and the repair cost to vehicles runs into millions. The solution to the ‘problem’ is not clear cut. Culling [the selective killing of animals] to control deer populations is one way in which numbers can be reduced, and the damage to woodland mitigated.  However, this approach has been met with opposition by many, including animal rights organisations.  There is the argument that whilst a reduction in deer numbers might fix some problems in the short term, the subsequent increase in plant growth and food availability might lead to increased breeding by the remaining deer and numbers would then increase again.  Also, unsuccessful or inaccurate shooting leads to animal suffering, mutilation and / or a lingering death.   Some might advocate rewilding and the introduction of apex predators (such as the wolf, lynx, wild cats*) as a means of reducing numbers but that might raise other problems! Deer have been 'part and parcel' of woodlands since mediaeval times, when the forests were used for hunting. In the Ashdown Forest, the number of red deer declined during the C17th,  and poaching was a factor in their decline. Fallow deer numbers also declined. [Fallow deer were introduced to England by the Normans around 1100 AD.]  The deer population roaming the forest has increased significantly in the recent decades, and now there are the relatively recently introduced species, muntjac and sika deer.   There are six species of deer in UK woodlands – the two native species, the red deer and roe deer and fallow, muntjac, sika and chinese water deer make up the four non-native species. The problem of over grazing is not unique to the Ashdown forest. For example, deer numbers in Scotland have doubled in recent years to almost a million since 1990.   Finding sustainable (and humane) solutions to the large numbers of deer is difficult. * Wildcats were once widespread in Britain, but by the end of the 18th century, they were to be found only in the northern regions. [caption id="attachment_34415" align="aligncenter" width="700"] Remnants of birch woodland near Loch Muick are subject to browsing by red deer (especially in the winter), so temporary fences have been put in place to allow for regeneration.[/caption]
Trees mitigate urban heat

Trees mitigate urban heat

by The blog at woodlands.co.uk, 14 June, 2024, 0 comments

With global temperatures rising and many places facing extremes of temperature, cities and urban environments often face the brunt of these climate extremes.  Cities absorb and hold onto the energy of the sun, creating ‘urban heat islands’. Recently, the temperature in New Delhi soared to a record high of 126.1oF (52.3oC), and other areas of India also suffered from the heat wave that claimed lives.  At a personal level, the shade of a tree can offer a place of refuge on a blisteringly hot day but a neighbourhood can benefit from the careful and strategic planting of trees.  Greater tree cover can mean that neighbourhoods are measurably cooler than those with few trees. If a heat wave is prolonged, then the physiological stress that people experience builds, affecting the old and young particularly.  Extreme heat / temperatures can also result in elevated levels of ozone, which affects people with asthma.  High temperatures may also be accompanied by high humidity and if the air has a high level of water vapour this makes it difficult for people to lose heat through sweating.  As water evaporates from the skin, its change of state (liquid to vapour) takes heat from the body. Researchers at UCLA analysed the ‘effects’ of four heat waves that occurred in the early years of the 21st century in Los Angeles, they focused on areas that varied in tree cover and pavements and road cover (essentially impermeable surfaces).  They also gathered information on ‘heat related’ visits to medical facilities.  They found that greater tree cover (and more reflective surfaces) reduced the number of heat-related medical interventions.   Whilst it might be agreed that increasing tree cover in urban settings is a good idea, there are practical problems.   Firstly, which trees to plant?  Ideally, the trees planted should be able to cope with the changing climate.  We don’t know what the climate will be like in 20 or 50 years but ideally the trees planted now should be able to cope with what nature might ‘throw at them’. Secondly, caring for the trees.  After planting, trees are vulnerable.  They need care and protection.  They need water - which is becoming an increasingly scarce resource in some parts of the world. Planting more trees needs to be coupled with increasing ‘green areas’ where water can permeate after rainfall into natural aquifers or water storage systems. Community involvement is also needed so that the trees are not only planted in areas where they will give the greatest benefit, but where people want them and will nurture them.   Los Angeles now has an Urban Forest Management Plan.  It aims to increase tree canopy in particular areas, locating areas to plant trees and collaborating with the residents of the areas.
Creating a 'Bender Chair'

Creating a ‘Bender Chair’

by Angus, 7 June, 2024, 1 comments

Lisa Bradford and her husband Paul run Willow Bushcraft a non-for-profit enterprise. They borrow a woodland in Kent owned by Woodlands.co.uk, and here Lisa writes about making a “Bender Chair”. Crafting a Masterpiece: This is how two students built a unique “Bender Chair” from hazel wood.    Creativity and craftsmanship came together in an extraordinary project undertaken by two dedicated students from a local school. These two students find it difficult in a mainstream school setting so attend a unit attached to the school. Over the course of a term, the two students transformed raw hazel rods into a stunning bender chair, showcasing both their hard work and newfound woodworking skills. The Inspiration for this journey began with a simple yet ambitious idea: to create a piece of furniture using traditional woodworking techniques. Inspired by Ben Law’s Woodland Craft book the natural beauty and flexibility of hazel wood, the students decided to build a bender chair. This type of chair, known for its distinctive curved lines and rustic charm, became the perfect canvas for their creative efforts.  The process involved coppicing hazel rods which had to be gathered from the woods. Both students learned the ancient technique of coppicing, a sustainable method of harvesting wood that encourages new growth. They explored March Wood, in Kent, to select and cut the perfect hazel rods, each one carefully chosen for its flexibility and strength.Next they assembled the chair by spending a couple of hours every week to their project, working with patience and precision. They crafted the frame first, measuring and cutting the hazel to size and ensuring the frame was sturdy and well-balanced. Week by week, the chair started to take shape. With their hazel rods in hand, the chair-makers began the meticulous process of shaping the chair. This involved bending the freshly cut rods into the desired forms for the seat, back, and armrests and tacking them into place. After weeks of diligent work, the students finally completed their bender chair. The result was nothing short of remarkable. The chair, with its gracefully curved lines and natural finish, was a testament to their hard work and creativity.  But the project provided the students with more than just a beautiful piece of furniture: it was a learning experience that taught them valuable skills in woodworking. More importantly, it gave them a profound sense of achievement and pride. They had started with a vision and, through perseverance and teamwork, brought that vision to life. Looking back on their journey, the students expressed immense satisfaction. They had not only learned about woodworking but also about the importance of patience, attention to detail, and sustainable practices. Their success with the bender chair has inspired them to take on more projects, and they hope to continue exploring the world of traditional craftsmanship. Forest Schools such as Willow Bushcraft are brilliant for hard-to-reach students who struggle in traditional classroom settings, and participating in forest school offers a transformative experience. Immersed in the natural environment, these students engage in hands-on, practical projects that ignite their curiosity and foster a sense of achievement. The forest school setting allows them to learn through doing, tapping into their innate creativity and problem-solving skills. This alternative educational approach not only enhances their self-esteem and confidence but also helps them develop essential life skills such as teamwork, perseverance, and adaptability. The “bender chair” demonstrates how outdoor learning can inspire a love for learning in even the most disengaged students.
The importance of biocrusts

The importance of biocrusts

by The blog at woodlands.co.uk, 4 June, 2024, 0 comments

The soil in many arid ecosystems (for example, savanna, deserts, & shrublands) is often covered by a thin layer of organisms, a community of lichens, mosses, liverworts, fungi, cyanobacteria and other microbes. They form a biocrust in the very top layer of the soil.  These organisms produce a variety of chemicals that glues together the soil particles.  Most biocrusts start of with a single type of organism (often a lichen or cyanobacteria, they are hardy). As these grow, they change the immediate environment so that others can then colonise the area so slowly the community grows.. The resulting biocrusts are important in helping reducing soil erosion and dust production.  Whilst dust can hold nutrients that will benefit plants as and when it is deposited, it can also have negative effects. Dust reduces water and air quality.  Dust storms can be truly massive and terrifying, for example, the 2009 Australian Dust storm. Occasionally, in this country we experience saharan dust that his been carried hundreds of miles on the wind.  If wind-blown dust lands on glaciers, snow or ice sheets then it affects the albedo.  The albedo is a measure of a surface’s ability to absorb and retain energy, or putting it the other way round, the ability to reflect heat / light energy.  Dark coloured objects tend to absorb more light energy than light coloured surfaces.  So if snow or ice becomes coated with dust, it will absorb more heat and may melt.   Biocrusts prevent many millions of tonnes of dusts entering the atmosphere each year.  It is thought that they may cover some 12% of the earth’s land surface.  Soil with a biocrust needs a far stronger wind before it starts to erode.  Sadly, like many other things, biocrusts are under threat due to climate change and shifting patterns of land use. [caption id="attachment_41261" align="aligncenter" width="675"] Church wall being colonised by Lichens[/caption] Biocrusts can also form on walls and buildings, for example, lichens and mosses colonise gravestones.  Whilst biocrusts have positive effects when they form on soils, it is thought that they can have deleterious effects on stone / brick surfaces due to the various organic acids and other chemicals that the colonising organisms can produce.  The production of these chemicals can degrade (weather) structures and lose their integrity / aesthetic appeal.   The Great Wall of China, which once stretched for some 8000+ kilometres, is protected by biocrusts in parts.  Construction of the wall started about. 200 BCE and continued (on and off) till the 1600’s CE.  Much of the wall has now been lost.  Some parts of the wall were made from stone and bricks (held together by sticky rice mortar). Other sections were constructed from ‘rammed earth’, made by compressing natural materials (eg. chalk, gravel, lime) with soil.  Some have regarded these sections of the wall as ‘weak points’.  Recent work by Bo Xiang and colleagues found that the ‘rammed earth’ sections were often covered by a biocrust, (of lichens, mosses and cyanobacteria).  This biocrust actually helps maintain the integrity of the wall by protecting it from wind and water erosion.  It reduces temperature extremes and the porosity of the wall, reducing infiltration and its water holding capacity.  All of these help maintain the integrity of these sections of the wall. If biocrusts are lost, through fire, climate change or human intervention then recovery can be problematic.  Organisms like cyanobacteria may recolonise a site quite quickly by organisms blowing in from nearby and undisturbed areas.  Full recovery of the crust and composition generally occurs more rapidly where the soil is fine  textured and moist. When the soil is coarse and dry then re-establishment of a biocrust may take hundreds or thousands of years. Thanks to Art for lichen image on church wall.