Category: The Conversation

Source: The Conversation – UK – By Anders Ahlström, Associate Professor, Department of Physical Geography and Ecosystem Science, Lund University

Most of Europe’s original natural forests have been transformed for agriculture and managed forests producing energy, paper and timber. The few remaining “old-growth” natural forests are relics of the past that illustrate how forests would have looked in the absence of human management. They can, therefore, tell us how people have transformed forests.

Most Swedish forests are so-called boreal forests. This type of coniferous woodland ecosystem encompasses most of the northern regions of the planet. These relatively cold regions have historically had low populations. Here, large-scale use of forests began relatively late.

In Sweden, modern forest management emerged in the 20th century. It involves cutting most trees in an area – clear-cutting – followed by planting and sowing of new trees, cleaning and thinning until the trees are clear-cut again up to 120 years later. The soil is also disturbed. It is very common to plough the soil and excavate trenches and ditches to remove water from forests.

After mapping and measuring the most natural old-growth forests in Sweden, we found that they differ much more from managed forests than previously thought, even if some of those managed forests looked old.

We found that old-growth forests store 78-89% more carbon than managed forests do, a difference in carbon storage larger than Sweden’s cumulative emissions from the combustion of fossil fuels since 1834. Our new study underscores the much larger carbon storage benefits that flow from protecting forests than using them to produce bioenergy and wood products.

Read more:
Sweden has vast ‘old growth’ forests – but they are being chopped down faster than the Amazon

Eight years ago, we started mapping the most natural lowland old-growth forests across the country. We focused on old-growth forest remnants in the least attractive areas for agriculture and forest management. We excluded these because they are usually slow-growing mountain forests and store less carbon than they would in the broader landscapes used for wood production. We then spent three years collecting samples and measuring the carbon content of the old-growth forests and compared with that of managed forests.

Soils are difficult to study. They store vast amounts of carbon but measuring that is difficult. The main methods to measure soil carbon have not changed in the last century. We dug 220 pits up to one-metre deep and took samples at different depths from across the country.

We analysed those soil samples in a lab and calculated carbon content in trees and dead wood from our measurements. We used the vast Swedish national forest inventory (a database collating annual sample-based survey results) to estimate carbon storage in managed forests and could then compare their carbon storage.

Managed forests are losing carbon

We found a huge difference in carbon storage between old-growth and managed forests. Old-growth forests store 87% more carbon in the trees, 334% more in dead wood, and 68% more in the soils than managed forests do. Overall, this amounts to 83% more carbon in old-growth forests than managed forests in Sweden’s boreal forests.

Most of that carbon is stored in the soils. Old-growth forests store as much carbon in their soils as the managed forests do in trees, dead wood and soils combined.

Our methods of comparing old-growth to managed forests show the sum of the total carbon accumulated in forests over time. This means the differences can be due to the loss of carbon in managed forests or a larger carbon uptake in old-growth forests.

We also took into account how the wood extracted from managed forests was used as wood products (for example, to build a house), which might not reach the atmosphere and produce climate change for decades to come.

In Sweden, around half of the harvested wood (or biomass) is burnt for heating and electricity production, around 25% is used for paper, and only around 25% ends up in products with relatively long lifetimes, such as houses, where they can form a sizeable storage over time.

When including carbon in all these products, primary forests still stored about 70% more carbon than managed forests. Actually, there’s more carbon in dead wood in the old-growth forests than in these wood products and dead wood in managed forests combined.

Why losing old-growth forest matters

The losses of carbon from forest management in Sweden are much larger than previously estimated. The difference in carbon storage between old-growth and managed forests (including harvested wood products) is equivalent to 1.5 times all Swedish fossil fuel emissions since 1834, or 220 years of Sweden’s fossil fuel emissions at current levels.

Of course, if wood products had not been used, other materials would have been used instead, some of which may have high carbon intensity (such as steel). This makes it difficult to estimate the overall effect on atmospheric greenhouse gases. However, there are now plenty of non-wood alternatives for heat and electricity (heat pumps, solar and wind energy, for example).

There are also vast areas of natural forests where the largest trees were logged many decades to a century ago, and they are likely in a state much closer to an untouched old-growth forest than an average managed forest is. Protecting these forests will, therefore, lead to a carbon sink as the large trees grow back, and avoid soil carbon losses from management.

We have previously reported on the ongoing loss of these old-growth forests in Sweden – a loss that is five to seven times faster than the loss of the Brazilian Amazon forest.

EU regulation currently protects all remaining old-growth forests in Europe, but definitions of old-growth forests are left to the member countries. In Sweden, the proposed definition of old-growth forest is based only on tree ages. This definition is not well anchored in science and sets a very high bar: 180 years in the north of the country and 160 years in the south.

These proposed Swedish definitions have been heavily criticised by conservation organisations for undermining the ambition of the EU nature restoration regulation to protect all remaining old-growth forests. If the proposed definition stands, little of the remaining unprotected old-growth forest will be protected and their logging will likely continue.

Protecting and restoring old-growth forests for carbon storage and biodiversity benefits can significantly contribute to limiting climate change in countries like Sweden.

Anders Ahlström receives funding from the Crafoord Foundation (20200755 & 20241108), Swedish Research Council (2021-05344, 2024-01983), BECC, Carl-Tryggers Stiftelse, Stiftelsen Extensus, Stiftelsen Längmanska kulturfonden, the Royal Physiographic Society of Lund, P.O. Lundells stiftelse, Jan Hain stiftelse för vetenskaplig teknisk forskning inom miljö och klimat, EU H2020 Climb-Forest (101059888), Blaustein visiting professorship at Stanford University and The Sustainability Accelerator at Stanford University.

Pep Canadell receives funding from the Australian National Environmental Science Program (NESP2)-Climate Systems Hub.

Didac Pascual does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Sweden’s ‘old-growth’ natural forests store 83% more carbon than managed woodlands – new study – https://theconversation.com/swedens-old-growth-natural-forests-store-83-more-carbon-than-managed-woodlands-new-study-277150

Source: The Conversation – UK – By April Rees, Lecturer, Biochemistry & Immunology, Swansea University

Endometriosis is a painful, debilitating condition affecting 10% of women worldwide. It occurs when tissue similar to the lining of the uterus (known as lesions) grows elsewhere in the body – usually within the pelvis.

Treating endometriosis can be difficult. Usually, treatment involves either preventing the growth of these lesions in the first place or removing lesions surgically. But even when lesions have been surgically removed, symptoms often don’t go away.

Traditionally, endometriosis has been thought of as a gynaecological condition. But mounting evidence suggests this characterisation downplays the disease’s complexity. Endometriosis appears to affect far more than just the reproductive system. According to a growing body of research, it influences immune function throughout the whole body.

Recognising it as a whole-body, immune-driven disease could help explain why symptoms range far beyond pelvic pain. It would also explain why treatment is so challenging and often does little to reduce symptoms.

A disease of the whole immune system

Inflammation – the body’s natural response to injury or illness – is a normal part of immune response. It also plays a key role in the menstrual cycle.

But if inflammation becomes chronic or uncontrolled, it can cause problems. This is seen in autoimmune conditions such as rheumatoid arthritis, where the immune system overreacts even when there is no threat.

Chronic inflammation is also known to play a central role in endometriosis. But the effects of this uncontrolled immune response may be far more widespread than previously thought. According to recent research, the immune response appears to extend into the bloodstream and other body systems. This may explain why endometriosis causes such far-reaching, whole-body symptoms.

Read more:
Endometriosis: how the condition may be linked to the immune system

In people with endometriosis, immune cells appear to be less able to clear lesions. Yet, at the same time, people with endometriosis have higher levels of immune proteins such as IL-6 and IL-1β in their blood. These immune proteins, known as cytokines, are a type of messenger released by cells to promote inflammation.

Together, these dysfunctional cells make it possible for lesions to grow and persist. This immune dysregulation also has ripple effects across the body, contributing to the wide range of symptoms sufferers experience.

For instance, many people with endometriosis experience debilitating fatigue, cognitive difficulties (such as “brain fog”) and widespread pain. These symptoms are rarely emphasised in clinical guidelines, yet they’re often as disruptive as pelvic pain itself.

Systemic inflammation offers a compelling explanation for these symptoms. Circulating cytokines, such as those mentioned earlier, are known to influence brain function and energy regulation. Higher levels of cytokines (including IL-6) have also been linked to poorer concentration, disrupted sleep and fatigue in some autoimmune and chronic pain disorders.

These same processes may be occurring in endometriosis. This suggests that invisible symptoms could be biological consequences of ongoing inflammation – not secondary effects of pain.

A dysfunctional immune system may also help to explain why emerging research hints at an overlap between endometriosis and autoimmune diseases.

In 2025, a large scale study looked at 330,000 patients with endometriosis and 1.2 million controls (people who didn’t have the condition). The study found that compared to the controls, people with endometriosis had roughly twice the odds of being diagnosed with an autoimmune condition – such as rheumatoid arthritis, lupus, multiple sclerosis or Hashimoto’s disease – within two years of their endometriosis diagnosis.

This doesn’t mean endometriosis is itself an autoimmune disease. But it does suggest shared mechanisms – including chronic inflammation, dysregulated immune cell activity, and problems with the immune system recognising the body’s own tissue properly.

These overlapping features strengthen the case for understanding endometriosis as a systemic immune disorder.

Reframing endometriosis

Viewing endometriosis in this way could transform how it’s diagnosed, treated and understood. It could also help us get closer to finding a solution for the condition.

Read more:
Endometriosis takes almost a decade to be diagnosed in the UK — our research has revealed some of the reasons why

Current treatments primarily target the reproductive system. But if endometriosis involves widespread immune dysfunction, then therapies that modulate immune pathways may offer more effective long-term relief.

Seeing endometriosis as a systemic condition can empower patients, as well. This reframing may help them understand that symptoms such as fatigue, joint pain, cognitive difficulties and immune sensitivity are not imagined or unrelated. Rather, they’re part of the condition’s broader biology.

Seeing it this way may support patients in advocating for themselves in healthcare settings, where systemic symptoms are often dismissed or deprioritised.

A systemic framing also opens space for patients to explore complementary management strategies aimed at reducing inflammation or improving overall wellbeing. While not curative, some people find gentle movement, stress regulation techniques and heat–cold contrast therapy helpful for managing pain or inflammatory flares.

A growing body of research shows that endometriosis is not solely a reproductive condition or a “bad period”. It’s a multi-system, inflammatory disorder with far-reaching health effects throughout the body.

Understanding endometriosis as a systemic immune disease is a crucial step toward better treatments, better support and, ultimately, better health outcomes.

April Rees receives funding from The Royal Society, Saint David’s Medical Foundation, and the Iraqi Government.

Laura Cowley receives funding from Health and Care Research Wales, Welsh Crucible, and the Learned Society of Wales.

– ref. Why endometriosis should be classified as a whole-body inflammatory disorder – https://theconversation.com/why-endometriosis-should-be-classified-as-a-whole-body-inflammatory-disorder-277994

Source: The Conversation – UK – By Lucy Stone, Assistant Professor of Children’s Literature, Dublin City University

When Winnie-the-Pooh gets stuck in Rabbit’s doorway after eating too much for elevenses, he is anxious and gloomy at the thought of having to forgo food for a whole week to get out. He asks Christopher Robin to read him “a Sustaining Book, such as would help and comfort a Wedged Bear in Great Tightness”.

A.A. Milne’s first children’s novel, Winnie-the-Pooh, does not exactly explain what a “Sustaining Book” is. But E.H. Shepard’s illustration provides some clue. Christopher Robin is shown reading an alphabet book with the word JAM for J visible on the page.

Jam is not Pooh’s favourite food, of course, but the word is more than apt. Pooh is in a jam, but being read to sustains him in his difficult situation by bringing him comfort. The book acts as “an aid in the crisis”, as former teacher Ethel Newell noted in a study of bibliotherapy for children in 1957.

Dating back to the early 19th century, bibliotherapy is a therapeutic approach that fosters reading books and other forms of literature to support mental wellbeing and healing.

This year marks the centenary of the first Winnie-the-Pooh book. Milne based the timeless tales on the nursery toys and games of his son, Christopher Robin – the boy who lives in the fictional world of the Hundred Acre Wood. His adventures with his bear, Winnie-the-Pooh, and friends (Piglet, Eeyore, Kanga and Roo, Rabbit and Owl), are equally gentle, clever and funny – and above all, comforting.

The book was an overnight success when it was first published (as was its sequel, The House at Pooh Corner, in 1928), and continues to cheer readers world over.

Literary caregiving

When Winnie-the-Pooh was published, books had been used in hospital libraries to alleviate the suffering of ill and wounded soldiers from the first world war. This idea of books as a source of comfort was not new, but there had been an increasing need in this period for what authors Sara Halsam and Edmund G.C. King term “literary caregiving”.

It was at this time that American journalist Samuel McChord Crothers coined the term bibliotherapy, and reading for wellbeing began to be recognised in the medical sphere.

Milne had himself fought in the war and experienced the suffering and trauma firsthand. Winnie-the-Pooh has long been considered a response to war, particularly in terms of the book’s nostalgia and depiction of psychological damage. But as an example of bibliotherapy – and how this too is tied to the war – Winnie-the-Pooh has received scant critical attention.

It is, of course, not just soldiers – nor bears in rabbit burrows – who need good books. Children stuck in hospital need them too. Undergoing medical treatment, especially for serious illness, can be one of the greatest challenges a child can face, as highlighted by the Read for Good initiative.

This hospital reading programme has run in 31 hospitals across the UK over the past 15 years, and has found that books and storytelling can “have a significant impact on children’s health, wellbeing and education” – at a time when children are facing illness or injury, missing out on schooling, and feeling isolated.

While Winnie-the-Pooh is not currently among the books in the Read for Good hospitals programme in the UK, the benefits of this children’s novel in hospitals have long been evident in initiatives in the US.

In 1999, the University of Florida launched a reading programme for the waiting room at the University’s Pediatric Continuity Care Clinic. One report describes a four-year-old girl who, nervously awaiting treatment, was calmed when Winnie-the-Pooh was read to her. And, just like Pooh being taught his ABCs, the child also learned new vocabulary from the story.

This programme is part of the Reach Out and Read campaign, endorsed by the American Academy of Pediatrics, which serves 4.8 million children across the US each year. Continued research efforts evaluate and maximise the impact of this initiative, and have found that there are positive results for children, families and clinicians.

More recently, in 2024 there was study of the parent-led Little Bookworms bedside reading programme in a neonatal intensive care unit (NICU) in Nashville.

Winnie-the-Pooh was selected as a book from childhood recommended by study participants to read with their infants, to “reduce anxiety and improve attachment for parents and caregivers who have infants in the NICU”. Supporting the wellbeing and engagement of carers in this way can help reduce some of the risks NICU infants face, including interruptions to language development which can affect subsequent literacy development.

Books to grow up with

More broadly, the potential of rereading a childhood book cannot be underestimated. Books read in childhood do not disappear, but “continue to unfold and inform the way in which we interpret the world” in our minds, as children’s literature expert Kimberley Reynolds of Newcastle University has established.

Paula Byrne, founder of the ReLit Foundation – which promotes reading as a way to combat stress and anxiety through “the slow reading of great literature” – has described the rereading of Winnie-the-Pooh in adulthood as therapeutic. Byrne believes the book has the capacity to grow with the reader from childhood to adulthood, offering new insights that can be appreciated in later life.

It is this ability of a book to grow with the reader that is of most help to children in distress, Newell suggested, providing “real armour” to children over a sustained period, and not just “a shot of penicillin for a particular infection”.

Over the past 100 years, Winnie-the-Pooh has grown from a book containing an example of bibliotherapy to a book for bibliotherapy in hospitals. As we celebrate the centenary of its publication, these ties to books as therapy for children and adults are well worth remembering.

Lucy Stone does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Winnie-the-Pooh at 100: this much-loved classic illustrates how books can boost our wellbeing – https://theconversation.com/winnie-the-pooh-at-100-this-much-loved-classic-illustrates-how-books-can-boost-our-wellbeing-277528

Source: The Conversation – UK – By Rachel Woods, Associate Professor, University of Nottingham; University of Lincoln

The trillions of microbes living in the human gut are increasingly recognised as important partners in human health. Scientists have linked the gut microbiome to several aspects of health, from metabolism and immunity to mental health.

A recent study suggests that these microbes may also influence an important aspect of fitness – muscle strength.

Muscle strength is a crucial feature of health for many reasons. It supports our joints and keeps our bones healthy, boosts athletic performance and even plays a role in metabolic health.

Muscle strength also helps us maintain independence later in life. As muscles gradually weaken as we get older, everyday tasks become harder and the risk of falls increases. Understanding what influences muscle strength is therefore an important part of healthy ageing research.

Read more:
Muscle is important for good health – here’s how to maintain it after middle age

A recent study explored whether specific gut bacteria might be linked to muscle strength. Researchers analysed the gut microbiomes of two groups of adults: 90 young adults aged 18 to 25 and 33 older adults aged 65 to 75.

Participants provided stool samples so researchers could identify the microbes living in their gut. The researchers used DNA sequencing to read genetic material from the microbes in each sample. By comparing these sequences with large reference databases, they could determine which bacterial species were present and how abundant they were.

Participants also completed several tests designed to measure muscle strength, including a handgrip test. This involves squeezing a handheld device as hard as possible. Grip strength is widely used in health research because it provides a snapshot of overall muscle strength. Lower grip strength has also been linked to a higher risk of premature death.

When the researchers compared participants’ muscle strength with the microbes in their gut, one species stood out. Higher levels of a bacterium called Roseburia inulinivorans were linked to stronger performance across muscle strength measures.

Finding a link like this is interesting, but it does not necessarily mean the microbe is responsible. Many things can be associated without one directly causing the other. Ice-cream sales and shark attacks both increase during summer, for example – but eating ice cream does not cause shark attacks.

So to investigate whether the bacterium might actually influence muscle strength, the researchers carried out additional experiments in mice. After reducing the animals’ existing gut microbes, they introduced Roseburia inulinivorans into the mice’s digestive systems.

Mice that received the bacterium developed noticeably stronger grip strength in their arms than those that did not. Their muscle fibres also became larger and shifted toward a type of fibre associated with more powerful movements (called type II muscle fibres).

Further analysis suggested Roseburia inulinivorans may influence how muscles use energy. In mice given R inulinivorans, several energy‑related pathways inside muscle cells became more active. At the same time, levels of certain amino acids (molecules used by all living things to make proteins) decreased in the gut and bloodstream.

The human data revealed another interesting pattern. Older adults in the study tended to have lower levels of Roseburia inulinivorans in their gut microbiome than the younger participants. This fits with the broader pattern of declining muscle strength that commonly occurs with age.

In humans, it’s still unclear whether gut bacteria influence muscle strength or whether stronger, more active people simply have different microbes in their gut. But the mouse experiments hint that this microbe can directly enhance muscle strength, so larger human studies will be needed to work out the direction of the relationship.

Muscle microbes

One possibility raised by this research is the future use of probiotics. These products contain live microbes intended to benefit health. If further studies confirm that Roseburia inulinivorans supports muscle strength in humans, it could be developed into a probiotic designed to help maintain muscle function as people age.

However, supplements are not the only way to encourage beneficial microbes in the gut. Diet plays a major role in shaping the microbiome.

Prebiotic fibres, which serve as food for gut bacteria, can also support their growth. This is because feeding these microbes allows them to become more established and active in the gut.

The name inulinivorans provides a clue about this bacterium’s preferred food source. It refers to inulin, a type of dietary fibre found naturally in foods such as onions, garlic, leeks, asparagus and chicory root. These fibres are known to support the growth of other beneficial gut bacteria, including members of the Roseburia group.

High‑fibre diets have long been associated with a range of health benefits. A large amount of research has linked higher fibre intake with lower risks of heart disease, type 2 diabetes and some cancers. These effects are probably driven by the complex activity of many different microbes rather than a single species. So at the moment, supplementation of any one individual bacterium is not a replacement for a diet high in fibre.

The study does have some limitations to note, however. The human groups were relatively small, and the experiments demonstrating cause and effect were conducted in mice rather than people. The older adults included in the study were also all male. Even so, the findings add to growing evidence that the gut microbiome may influence far more aspects of health than previously thought.

For now, the advice for supporting both muscle strength and a healthy microbiome remains reassuringly familiar: regular strength‑building exercise and a diet rich in fibre.

Rachel Woods does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Could a gut microbe influence muscle strength? – https://theconversation.com/could-a-gut-microbe-influence-muscle-strength-278346