What the Forest Gives Us: Brain Benefits Hidden in Nature

Chinooks aside, winters are long in Calgary. Period. Piling on the layers of winter repellant to go for a walk feels like a chore and for several months of the year we simply don't get enough time outdoors.   

And then...there's June. I love this time of year. Suddenly everything is greening up. Sprouts are pushing their way upward at lightning speed, out of their deep winter sleep, and rejoicing in the warm sunshine. Fuzzy little chicks have grown some adult feathers - and confidence - and will soon be ready to fledge while their parents are still bringing home take-out. Flowers are blooming like gangbusters. Thunderstorms roll in and make their presence heard and felt with the energy of wild elephants. The air smells like summer and our bodies awaken with renewed energy as we plunge our fingers into the soil, carrying new life into the ground, which we proudly call bedding plants. Life feels good.  

This is the time of year when I get to re-set, and I'm so grateful. Spending time in forests is critically important for me – both my mind and body. It's when I remind myself of what my baseline is...what my body feels like without tension. This annual re-set only barely carries me through the following winter (the sunny winter days help), so I literally breathe, absorb, feel and nourish as much as I can in these few short summer months. 

We have habituated to the mechanical and the concrete; the honking and shouting; the apprehension and anxiety...but there still exists a primal need for stillness in each of us.  

Anyone who has spent time in a forest intuitively recognizes its soothing effect as the absence of the busy urban environment begins to exert a profound impact on the nervous system. The effect is so dramatic that scientists have been compelled to understand biology behind it. In January this year, researchers in the Department of Psychiatry at McGill University and at the Adolfo Ibñez University in Chile published an extensive review of the subject. In "Your brain on nature: A scoping review of the neuroscience of nature exposure" they summarized 108 studies involving brain imaging conducted over the past 20 years, including electroencephalograms (EEGs) and magnetic resonance imaging (MRI). Within those 108 studies (conducted in different parts of the world and in different laboratories) was an entire spectrum of levels of exposure to nature, ranging from simply looking at a picture of nature on a computer to complete immersion in a forest. They compared responses to sound and smell stimuli of urban and nature settings. They also compared analyses of treadmill walking, urban crowded walking in concrete environments, urban uncrowded walking in green parks, and forest walking, among many other scenarios. 

What Does Time in Nature Do To Your Brain? 

Thanks to the efforts of the teams at McGill and Adolfo Ibñez, we now have a model for how the brain responds to nature, in a cascade of 4 interconnected levels. Here's a simplified version: 

Nature's Restorative Effects 

🌳 Shift in how we process sensory stimulus: Nature gives the cognitive portion of our brain a break, allowing us to focus better and renew our ability to be patient. Patterns in nature become easier for the brain to process and require less mental effort than the fast-paced and visually dense stimuli found in cities or online. 

🌳 Stress systems settle: As sensory load eases, the body shifts out of fight-or-flight mode. Heart rate slows, breathing deepens and brain regions involved in threat detection, such as the amygdala, show reduced activity. 

🌳 Attention restores itself: As stress levels are reduced, the task-driven attention used in everyday life gives way to a more restorative mode of attention guided by the environment. 

🌳 Mental rumination quiets: Brain networks linked to repetitive self-focused thinking become less active, supporting a calmer sense of self. 

How much exposure to nature do we need (and is a house plant enough)? 

The summary of studies over that past 2 decades indicates that simply looking at images of nature for three minutes already had an impact on people’s stress levels, attention, mind and body regulation. And yes, your houseplant can be a source of calmness, or even a focal point during meditation. 

Everyone benefits from exposure and interaction. The right “dose and duration” depends on each person’s circumstances. 

On one end of the spectrum, just being placed near a window with a natural view (compared to a view of a brick wall) is associated with faster healing and less pain medication for surgical patients. Indoor plants and photos of natural spaces bring benefits when we are indoors. Virtual environments using video also have measurable benefits. 

For those who are able to be outside, there is good evidence that 30 minutes a week is helpful and that a total of 120 minutes a week is consistently associated with higher levels of physical health and self-reported well-being. One particular study with University students on the impact of forest walking focusing on student learning motivation, engagement and attentional fatigue, found that after eight weeks of a 30-minute weekly walk in the woods, students demonstrated cumulative benefits in their learning engagement. 

If walking in a park or doing a hike in a forest works for you, great! Keep it up! But if you want to get a more immersive experience, consider Forest Bathing. 

What is the history and practice of forest bathing? 

The Ancient Greeks revered medicine and mythology; they understood the need for solace and restoration and built Sanctuaries dedicated to healing. These buildings, likely surrounded by natural vegetation and curated gardens, held a deeply spiritual connection to the healing powers of the surrounding space, which endures among the ruins today. 

In the Middle Ages, Monks (especially within the Cistercian, Carthusian, and Benedictine orders) often sought out deep isolation and forests to retreat from worldly distractions. The monks had an intricate understanding of the outdoors for survival and healing. They cultivated extensive monastery gardens and studied botany to create natural medicines from leaves, bark, and roots. 

In modern times, research on the benefits spending time in forests began in the 1980s and 1990s in Japan, which found measurable changes in stress hormones following exposure to nature. This practice is known as shinrin-yoku and translates to “forest bathing.” This led to a growing scientific interest in measuring the physical and mental benefits of exposure to nature. Many more recent studies have discovered improved immune functioning after prolonged periods in the forest.  

The pioneering research of Dr Suzanne Simard, a Canadian Professor of Forest Ecology, has finally lent credibility to anthropomorphic language regarding trees by rigorously mapping subterranean fungal networks (mycorrhizae) using DNA analysis and carbon isotopes. By providing empirical data, she transformed metaphors of tree "communication" and "intelligence" and "families" into verifiable science. Through what she calls the "Wood Wide Web", communication between trees via chemical signals serve not only as cues regarding danger (such as pest infestations), but also as a botanical prescription for human health.  

Trees emit airborne chemicals, called phytoncides, to protect themselves from insects. As we breathe in these phytoncides, our bodies respond by increasing the number and activity of a particular kind of immune cell, called natural killer (NK) cells. This response boosts our immune activity and effectively protects our own bodies as well. 

This is a situation that completely works in our favor when we're stressed. When we're under pressure and feeling anxious, levels of the stress hormone noradrenaline are increased. Unfortunately, this actually works against our immune system by slowing down the activity of those NK cells. But as we just saw, phytoncides increase the activity of our immune systems. 

It naturally follows that if you're stressed, spending time in trees, where the air you breathe is full of these natural stress-reducing chemicals, is doing you more good than you might realize.  

Forest therapy is literally healthcare for your brain.  

Considering health policy, time spent outdoors can now be prescribed and your healthcare plan may actually cover this. I spoke with Occupational Therapist and Certified Forest Bathing Therapist Anne Robillard recently and she explained how this works here in Calgary.  

As my newest Wellness Partner, she complements brain health with stress reduction, mindfulness and mental wellbeing in a forest setting, and I am absolutely thrilled to have her in my Network!  

Check out our podcast here

Further Reading – from my personal library: 

Discover Dr Suzanne Simard's brilliant wisdom on the social connection within forests in her book "Finding the Mother Tree" 

Science, health and environmental journalist Zoë Schlanger writes of the intellectual struggles of scientists as they try to make sense of new discoveries about what a plant is in "The Light Eaters" 

Finally, the book that profoundly altered my perception of everything green, Robin Wall Kimmerer's "Braiding Sweetgrass".