Plant happiness equation: People + Trees = :)

As a confirmed botanophile, I neither need to be told nor reminded that trees – and plants more generally – make one happy. But I also acknowledge that there are people who might not agree with that notion. So, for those who are still not yet convinced of the positivity-promoting potential of plants – and for those who appreciate the occasional reminder – it’s official: “Living Near A Forest Will Make You Happier”.

A view of Jesmond Dene Newcastle upon Tyne taken in 1975.
A view of Jesmond Dene Newcastle upon Tyne taken in 1975. Image: Newcastle Libraries / Flickr

This headline is the eye-catching hook to draw you in to an article by Trevor Nace that reports the work of Simone Kühn et al.. And one has to admit that straightforwardly worded news item is much more likely to catch one’s attention and encourage one to read more than the research article it’s based on. Because the scientific paper has the much less clear-what-the-meaning-is title “In search of features that constitute an “enriched environment” in humans: Associations between geographical properties and brain structure”. And which is not helped that much by an abstract that concludes that “forests may have salutogenic* effects on the integrity of the amygdala” (although that does get a little closer to Nace’s headline…).

The amygdala is a part of the brain that is involved in several functions including arousal, responses associated with fear, and emotional responses. Importantly, city dwellers living close to a forest were more likely to have physiologically healthy amygdala and were therefore presumably better able to cope with stress .

Previous studies had shown improvement in general wellbeing and/or mental health in those who had access to nature and ‘green spaces’. But, Kühn et al’s study is the first that demonstrates physical differences in the brains of those with such proximity to green areas, and which may have a direct effect upon mental well-being. Which sounds encouraging. However, as bedevils all such studies, it was not possible to determine cause and effect, i.e. whether living close to a forest had a positive effect on the amygdala or whether people with healthier amygdala were more likely to choose to live near forests. To summarise the study in the most positive, optimistic way, getting ‘close’ to nature is good for you, but arguably living close to nature is – probably… – even better. Or, if you must live in a city, try and live close to a wooded area. Interestingly, it’s apparently living close to a forest that’s good, not actually living in the forest.

Sticking with the amygdaloidal dimension and the sense of fear associated with that part of the brain I wonder if that’s related to a deep-seated fear of wolves – who allegedly eat grandmothers – or witches who kidnap children – both of which malevolent lifeforms lurk within forests (according to those highly-respected documenters of such natural phenomena, the Brothers Grimm)? But, if you don’t live near a forest, or are unable to visit one (or are just scared of forests), fear not, a new discovery may enable you to get your daily ‘tree-fix’.

Elias Neeman et al. have determined the molecular structure of α-pinene in the gaseous phase – the state this molecule is in when released from trees such as pines (11). It is not unlikely that this volatile compound could contribute to the well-beingness associated with forests. If this fragrance could be bottled, a short squirt of this monoterpene could create the calm-inducing effects of a forest wherever you are. And for those private sylvan moments, a little of the hydrocarbon added to your bath-water could fill the room with the soothing smell of the forest.** And this latter full-sensory, immersive experience would give a new meaning to the Japanese concept of ‘forest-bathing’ – shinrin-yoku – a phenomenon with proven healthgiving benefits. Soaking in a pinene-enriched bath may well be as good as the real thing – providing you can overcome any fear of drowning!

* Salutogenic is a term attributed to Prof. Aaron Antonovsky and refers “to a scholarly orientation focusing attention on the study of the origins of health and assets for health, contra the origins of disease and risk factors” [21]. That is to say, its focus is on the positive, health-promoting rather than the negative, disease-causing.

** However, until that has come to pass, and as you await your next forest-proximity experience, you can always wallow in images of trees and forests at the Atlantic. At least some of those are guaranteed to make you smile and improve your sense of well-being…

Reference List

Kühn, S., Düzel, S., Eibich, P., Krekel, C., Wüstemann, H., Kolbe, J., … Lindenberger, U. (2017). In search of features that constitute an “enriched environment” in humans: Associations between geographical properties and brain structure. Scientific Reports, 7(1).

Maas, J. (2006). Green space, urbanity, and health: how strong is the relation? Journal of Epidemiology & Community Health, 60(7), 587–592.

Alcock, I., White, M. P., Wheeler, B. W., Fleming, L. E., & Depledge, M. H. (2014). Longitudinal Effects on Mental Health of Moving to Greener and Less Green Urban Areas. Environmental Science & Technology, 48(2), 1247–1255.

Beyer, K., Kaltenbach, A., Szabo, A., Bogar, S., Nieto, F., & Malecki, K. (2014). Exposure to Neighborhood Green Space and Mental Health: Evidence from the Survey of the Health of Wisconsin. International Journal of Environmental Research and Public Health, 11(3), 3453–3472.

Neeman, E. M., Avilés Moreno, J. R., & Huet, T. R. (2017). The gas phase structure of α-pinene, a main biogenic volatile organic compound. The Journal of Chemical Physics, 147(21), 214305.

Park, B. J., Tsunetsugu, Y., Kasetani, T., Kagawa, T., & Miyazaki, Y. (2009). The physiological effects of Shinrin-yoku (taking in the forest atmosphere or forest bathing): evidence from field experiments in 24 forests across Japan. Environmental Health and Preventive Medicine, 15(1), 18–26.

Hansen, M. M., Jones, R., & Tocchini, K. (2017). Shinrin-Yoku (Forest Bathing) and Nature Therapy: A State-of-the-Art Review. International Journal of Environmental Research and Public Health, 14(8), 851.

Ideno, Y., Hayashi, K., Abe, Y., Ueda, K., Iso, H., Noda, M., … Suzuki, S. (2017). Blood pressure-lowering effect of Shinrin-yoku (Forest bathing): a systematic review and meta-analysis. BMC Complementary and Alternative Medicine, 17(1).

Oh, B., Lee, K. J., Zaslawski, C., Yeung, A., Rosenthal, D., Larkey, L., & Back, M. (2017). Health and well-being benefits of spending time in forests: systematic review. Environmental Health and Preventive Medicine, 22(1).

ANTONOVSKY, A. (1996). The salutogenic model as a theory to guide health promotion. Health Promotion International, 11(1), 11–18.

Mittelmark, M. B., & Bauer, G. F. (2016). The Meanings of Salutogenesis. The Handbook of Salutogenesis, 7–13.