A Forest Stroll is Good for Body and Soul

A Forest Stroll is Good for Body and Soul

At RTB we want to help others see that wherever we look in nature we find things that reinforce confidence in the God of the Bible. The words of Paul, found in his letter to believers in Rome, suggest that these evidences should be everywhere we look. Recently, a hike and a video spotted on social media brought just such an example to my attention.

I like to hike. I much prefer forest hiking to hiking in most other terrains. Just a few weeks ago, I saw a short video on social media about “forest bathing.” This video enlightened me, drawing my attention to studies that suggest my desire to hike among trees rather than in bare, rocky terrain, semi-arid or desert terrains or even open meadows may be because there is a truly greater salutary effect of walking among the trees.

While recently hiking among trees and thinking about Paul’s words in Romans 1 regarding the ubiquitous evidences for God’s existence and character, I became aware that trees, and plants in general, robustly demonstrate God’s extravagance in creation. Their beauty and diversity are good for the soul, reminding us that God has created all things that we might delight in them and in his goodness. But there’s more than that. Trees and plants are part of God’s extravagant provision for our flourishing.

A Forest Stroll Will Do the Body and Soul Good

It seems that forest hiking—actually the hiking is optional—has been studied and promoted in Japan for quite some time. It was adopted as part of their national health program in 1982. A quick review of the recent literature produced studies that link forest bathing—just spending time (as little as 15–30 minutes) in the forest—with all kinds of health benefits, including physiological and psychological ones that can last many days (7 to 30) after your “splash” in the trees!1

Although many studies include potential risk of bias and some have low sample sizes, forest bathing includes psychological benefits such as reducing tension/anxiety, depression, anger/hostility, fatigue and confusion, and increasing vigor.2 Physiological benefits include decreased salivary and serum levels of cortisol (a stress hormone), adrenaline (detected in urine analysis), heart rates, blood pressure (even in hypertensive and high-risk groups), and blood glucose levels. Heart rate variability analyses also indicated increased physiological relaxation, increasing parasympathetic and reducing sympathetic nervous system activity. Additional benefits to immune function have also been reported, including increased natural killer (NK) cell activity. NK cells are part of the innate immune system and are among the immune system’s first responders to infection.

Phytoncides and terpenes, organic compounds found in tree and plant oils, fill the forest air and have been indicated as contributing to anti-inflammatory, anti-tumorogenic, and neuronal protection activities, increased NK-cell activity, and physiological relaxation markers in human studies. Forests also have relatively higher atmospheric levels of negative ions that help clear the air of allergens and pollutants. So breathe deeply while in your forest bath—no potential for drowning here—and great potential for better health.

But plants do not only benefit us through the production of essential oils, they also sustain ecosystems and human life at the base of the carbon cycle and food chain. Oxygen and carbohydrates are produced in rich abundance as mere byproducts of plants’ photosynthetic activities, yet they benefit all other forms of life on planet Earth!

Extravagance of Primary Producers

Members of the kingdom Plantae are extravagant in the amount of food they produce from photosynthetic processes. During photosynthesis, plants turn water, sunlight, and carbon dioxide into oxygen and simple and complex sugars, including glucose, fructose, and starches. Plants are able to store energy in the form of these carbohydrates for use when growing conditions do not sustain continued production. But plants produce orders of magnitude more food (sugars) than they need themselves. Because of their ability to take inorganic compounds like carbon dioxide and water and produce biologically essential carbohydrates, plants are among Earth’s primary producers. Primary producers are foundational in sustaining the diverse, life-rich ecosystems of planet Earth.

Go Green

As you bathe in the forest greenery, note that the green color is due to the abundance of chlorophyll, a pigment at the heart of plants’ photosynthetic activities and primary producer status. Chlorophyll comes in a variety of forms and is critical for the photosynthetic production of oxygen and sugars. The porphyrin rings of chlorophylls are able to capture or harvest energy from sunlight. As chlorophyll absorbs light, the electrons in the porphyrin ring are excited. Each photon of light excites one electron in the porphyrin ring. These excited electrons are easily transported from one molecule to another but will eventually be emitted as fluorescent light if not ejected and captured for use in the photosynthetic pathway.

In order for the excited electrons to be ejected for photosynthetic reactions and not lost through light emission, chlorophyll molecules must be held in specific orientations within protein aggregates known as antenna complexes. These complexes are highly specified structures embedded in thylakoid membranes within the plant’s chloroplasts. Antenna complexes harvest light energy and allow rapid energy transfer to a pair of chlorophyll a molecules or acceptor molecules at reaction centers. The thylakoid membranes not only hold antenna complexes and reaction centers necessary for photosystems I and II but also the electron transport chain molecules essential for coupling these two systems.

Each reaction center allows multiple chlorophyll molecules to release high energy, excited electrons to acceptor molecules. When chlorophylls release the high energy electrons, they receive electrons from the splitting of water molecules. The splitting of water molecules not only provides donor electrons for the chlorophyll but also provides molecular oxygen and hydrogen ions. The hydrogen ions escape the thylakoid membrane via ATP synthase and create ATP in the process. ATP is critical for the plant’s survival and for the production of sugars. The hydrogen ions also convert NADP+ into NADPH.

Carbon dioxide, along with ATP and NADPH, enters the Calvin cycle for the synthesis of glyceraldehyde-3-phosphate (G3P), a precursor to glucose synthesis. The Calvin cycle is often simplified in textbooks and elsewhere, but it is far from simple! Occurring in the stroma of the chloroplasts, the Calvin cycle requires multiple additional components, including a five-carbon acceptor molecule—ribulose-1,5-bisphosphate (RuBP)—magnesium ions, RuBisCO—an RuBP carboxylase/oxygenase enzyme comprised of a complex of protein subunits3and at least eleven other key enzymes to ensure proper carbon fixation (G3P production)!4 Three turns of the Calvin cycle require 3 CO2 and 3 RuBP molecules and produce 1 G3P molecule. Two G3P molecules are needed for one molecule of glucose. The equation below simplifies the Calvin cycle, balancing input and output components, but it leaves out numerous enzymes and metal ions necessary for the conversion reaction to take place.

From this brief description, one can see that the photosynthetic process requires more than chlorophyll alone. Complex systems are required, which include thousands of chlorophyll molecules, protein scaffolds in antenna complexes, thylakoid membranes, electron transport molecules, and complex metabolic pathways (Calvin cycle) entailing dozens of other biomolecular compounds, and at least 11 different enzymes for simply capturing the sun’s energy and transforming water and carbon dioxide into the life-critical compounds for nonprimary producers. Sure, chlorophyll is one of the most ancient and fundamental components sustaining life on Earth—but its support system is far from simple! The photosynthetic system that allows chlorophyll to perform its critical function is extremely complex yet essential, drawing attention at the molecular level to extravagant, complex, and intricate designs.

At RTB we’re often asked, and therefore thinking about, evidence for God’s existence and the challenges that naturalism poses to biblical faith. As I consider the underlying complexity of photosynthesis, which is the most basic process of energy harvesting in Earth’s ecosystems, the competing worldview of Darwinian naturalism seems much less persuasive. The amazing nature of trees and other photosynthetic plants that produce far more food resources than they themselves need while serendipitously providing oxygen as an unneeded byproduct for sustaining all animal life is one such example that fits nicely in the biblical worldview of God’s extravagant provision and progressive creation of finely balanced ecosystems. Meanwhile, naturalism’s nonteleological selection of the fittest seems a truly incredulous claim to account for such interdependent highly complex phenomena.

Breathe Deeply

So breathe deeply on your next forest hike or stroll through the trees. Consider the lilies or other plants that surround you. Join with Paul and me in giving praise to God who reveals his power and attributes in fine tuning our symbiotic, complex creation that sustains his image bearers and all other living things. Revel in the extravagant provision of the Lord as you consider the more-than-abundant food—not to mention the oxygen filling your lungs—produced by the surrounding trees. Consider his attention to intricate, marvelously more complex details and fine tuning as you recall the basic, but not simple, process of photosynthesis. It’ll do your body and soul good.

  1. Margaret M. Hansen, Reo Jones, and Kirsten Tocchini, “Shinrin-Yoku (Forest Bathing) and Nature Therapy: A State-of-the-Art Review,” Yoshifumi Miyazaki, Hiromitsu Kobayashi, Sin-Ae Park, Chorong Song, eds., International Journal of Environmental Research and Public Health (July 28, 2017): 14(8):851, doi:10.3390/ijerph14080851; Genxiang Mao et al., “The Salutary Influence of Forest Bathing on Elderly Patients with Chronic Heart Failure,” William C. Sullivan, Chun-Yen Chang, eds., International Journal of Environmental Research and Public Health (March 31, 2017): 14(4):368, doi:10.3390/ijerph14040368; Chorong Song, Harumi Ikei, and Yoshifumi Miyazaki, “Physiological Effects of Nature Therapy: A Review of the Research in Japan,” Paul B. Tchounwou, ed., International Journal of Environmental Research and Public Health (August 3, 2016): 13(8):781, doi:10.3390/ijerph13080781; Bum Jin Park et al., “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 (January 2010): 15(1):18–26, doi:10.1007/s12199-009-0086-9; Yuki Ideno et al., “Blood Pressure-Lowering Effect of Shinrin-yoku (Forest Bathing): A Systematic Review and Meta-Analysis,” BMC Complementary and Alternative Medicine (August 16, 2017): 17:409, doi:10.1186/s12906-017-1912-z; Byeongsang Oh et al., “Health and Well-Being Benefits of Spending Time in Forests: Systematic Review,” Environmental Health and Preventive Medicine (October 18, 2017): 22:71, doi:10.1186/s12199-017-0677-9; Qing Li, “Effect of forest bathing trips on human immune function,” Environmental Health and Preventive Medicine. 2010;15(1):9-17. doi:10.1007/s12199-008-0068-3; Kyoung Sang Cho, et al., “Terpenes from Forests and Human Health.” Toxicological Research. 2017;33(2):97-106. doi:10.5487/TR.2017.33.2.097.
  2. In my opinion, most, if not all, of these studies lack the most appropriate control group, which would be individuals in a nonurban, nonforest area—perhaps a farm or rural environment. The reason I suggest this is because urban environments (the control group in all studies I read) introduce confounding stress factors such as noise, pollutants, and crowding that are often not taken into account.
  3. RuBisCO enzymatic activity is regulated by numerous factors, including ions, RuBisCO activase, ATP/ADP and reduction/oxidation states, phosphate and carbon dioxide. The various factors influencing RuBisCO activity directly affect phase 1 of the Calvin cycle. See Regulation of the Calvin cycle for more details. RuBisCO enzymes are the most abundant proteins on Earth and exist in multiple forms. RuBisco enzymes found in higher plants are hexadecamers composed of eight large (L) and eight small (S) subunits, encoded by a single chloroplast gene (rbcL) and two nuclear genes (RBCS1/2), respectively. See Learn more About RuBisCO, “Organellar and Metabolic Processes.”
  4. Key enzymes in the Calvin cycle. The Calvin cycle is not solely dependent upon functional RuBisCO. In addition, 6 ATP molecules, the enzyme phosphoglycerate kinase, 6 molecules of NADPH, and the enzyme glyceraldehyde 3-phosphate dehydrogenase are all needed for production of one excess molecule of G3P. Additionally, during the third phase of the Calvin cycle, regeneration of RuBisCO occurs. This specific phase involves a series of reactions in which there are a variety of enzymes required to ensure proper regulation. This phase is characterized by the conversion of G3P—which was produced in an earlier phase—back to ribulose 1,5-bisphosphate. This process requires ATP and specific enzymes. Enzymes involved in regeneration are complex and include: triose phosphate isomerase, aldolase, fructose-1,6-bisphosphatase, transketolase, sedoheptulose-1,7-bisphosphatase, phosphopentose isomerase, phosphopentose epimerase, and phosphoribulokinase. See: Regulation of the Calvin cycle.