We know this: Nature is good for our health. This seemed an odd idea not so long ago, yet we are coming to understand how our behaviours and choices can produce contentment, happiness and greater longevity. They could, too, help protect our fragile planet under threat from our over-consumption of finite resources and our lack of care. What if we spent a bit more time enjoying birdsong and sunsets, or sitting with friends in the park or garden?

These two new books add to the growing literature on Nature and health, and they are very different beasts. They illustrate the importance both of evidence and of storytelling. Sometimes story is more important, as it can capture emotion and create a sense of shared human experience; sometimes evidence is key, as it can disprove ideas that seemed hopeful as well as suggest critical courses for policy and action.

At the University of Essex, we have conducted 15 years of research into the health benefits of activities in natural places. This green exercise in a wide variety of contexts shows that physical activity in the presence of Nature improves health and wellbeing. We found no groups who have not benefited: all ages, genders, ethnicities and social classes respond positively to green exercise. All natural environments are beneficial: from urban parks to biodiversity-rich forests, from small and local to large landscapes, from domestic gardens to the farmed and wild. We also know that the deliberate therapeutic use of natural environments – gardens, allotments, care farms, wild places – has short- and long-term positive effects on people under mental stress, including at-risk children, refugees, probationers, people with dementia, office workers, and people with mental health problems. The natural environment is now understood to provide vital health services as well as other ecosystem services.

In 2017, we launched our Manifesto for a Green Mind in Resurgence & Ecologist (Issue 301), calling for universal changes to policy, planning and behaviours that would deliver health and economic benefit to whole countries. Six lifestyle-related conditions now dominate the costs to the UK’s National Health Service (NHS), and Nature can play a positive role in the prevention of and recovery from all of them The way we live today is killing people in affluent countries – through cardiovascular disease, obesity, type 2 diabetes, mental ill health, dementias and loneliness. These cost the NHS £60 billion per year.

The idea of the manifesto was to propose that every child spend time outdoors every day, every adult be physically active daily, every adult learn a new skill or craft throughout life, every care home have a garden and every hospital be redesigned on greener, pro-social principles. And while we’re at it, how about every bit of fossil fuel be left in the ground forever?

Florence Williams’s The Nature Fix is a cogent, clear and engaging book of tales of exploration. Williams calls this a “leafy errand”, as she explores research ideas, places and personal discovery. We learn that Nature makes us happier and more creative. There are some old tropes, running over somewhat outdated research, drawing on the biophilia hypothesis in passing, and referring too often to the landscapes typical of temperate and affluent countries. But these are minor quibbles: this is a book to engage and persuade the sceptic as well as the committed.

Clemens Arvay builds his book The Biophilia Effect around the bonds between humans and Nature. I’ll be blunt. This is an interesting book that I also found frustrating and often irritating. There are long discursions into multi-page boxes that disrupt rhythm, often dwelling on the experiences of particular individuals that do not invite sympathy. A “warped oak” impresses the author as “wild and fierce” appearing on the stormy coast of Wales, yet earlier, too, is growing on the Atlantic coast of Ireland. Elsewhere herbivores are called predators of trees; and building on the green vision of the King of Pop, Michael Jackson, seems misguided. But it is biophilia that receives uncritical attention. It is an appealing idea: early hominids spent lots of time in green places, particularly savannahs with open grassland and trees, so this is why we have innate connections to Nature, especially as these landscapes are repeated in the urban parks of many cities. There are numerous objections: many hominids have lived and evolved in deserts, tundra, steppe and marsh, and have completely different cultural preferences. How too, would such an innate mechanism become coded into our DNA? Above all, it is simply not needed as an explanation – though it is a good story.

In Nature Fix, Williams writes richly about research, therapies and planning in Korea, Japan, Singapore, Finland, the UK and the USA. Her book is framed as a journey, the pilgrim’s long trip along the camino. Here Williams starts with a problem: moving from the wilds of Colorado to underneath the flight path in Washington DC. She is agitated, and she searches for a personal Nature fix as well as the roots of persuasive new research. She explores the effects of sound, both good and bad, the aromas of the forest and the terpene-based compounds that seem to make forest-bathing work. She explores the visual: is it the colours of Nature that matter, or the context? The green of tree and blue of sky, or your recollection of a happy picnic beneath such a tree? Williams is reflective: “I find the compulsion to break apart the pieces of Nature, and examine them one by one, interesting and troubling.” When you open all the doors, she observes, that is when the real magic can begin. We learn of dose responses, and that spending five hours per month outdoors in Nature is vital; and that in greener neighbourhoods death rates are lower for everyone.

One thing is hinted at but largely missing: it is the health outcomes of attentiveness and immersion. Nature provides this opportunity, but so do social contexts and the practice of crafts and arts. One of the legacies that made us human is our prefrontal cortex (PFC), wherein reside the language centre, memory, sensory processing, and all the skills of curiosity, planning and how we can imagine what other people think and feel. The PFC makes us human, but it has no off-switch. So when we are not focused, our minds wander. Sometimes this is good – it leads to creativity. But more often it is not. A wandering mind is unhappy and stressed, tending to visit memories of the past and imagine scenarios of the future.

We now know there is an off-switch. But it requires us to behave in a certain way – to be attentive, mindful and immersed in something. This might be a walk, gardening, knitting, the daily crossword, tai chi or your local book group; it might be mindfulness, meditation or prayer; it might be sitting on the beach watching the waves and clouds. Consume the view, share time with others, learn a skill: all activities that burn few of the Earth’s resources but bring wellbeing and happiness. We have stopped, calmed, forgotten our anxieties and stresses, for a while, and we feel a small sense of peace. This is the switching on of the green mind.

Jules Pretty is Professor of Environment and Society at the University of Essex, and author of The East Country: Almanac Tales of Valley and Shore (2017).