The Mirror of Nature in the Human Body

The connection between people and nature is not symbolic—it is anatomical. The designs we see in trees, rivers, and root systems are also found within our own biology. The delicate branching of blood vessels beneath the skin mirrors the venation of leaves. The protective bark of a tree finds its likeness in the layers of human skin. The roots that reach deep into the earth reflect the way our neurons stretch and connect across the architecture of the brain.

Even our lungs expand and divide like the limbs of a tree, designed to maximise surface area for the exchange of air. Inhaling beneath a canopy of trees is more than a peaceful experience. It is a quiet act of physiological recognition. We are made of the same logic as forests—interconnected, adaptive, and alive.

This structural similarity is more than poetic. It is a biological reminder that we are part of nature, not separate from it. When we damage the systems around us, we compromise the systems within us. And when we create environments that nourish nature, we create environments that heal people.

Physical Activity and Urban Design

The modern city has made movement difficult. Heavy traffic, poor air quality, crowded streets, and a lack of inviting public spaces all contribute to an epidemic of physical inactivity—one of the leading causes of death worldwide [3]. But urban greenery has the power to shift this trajectory.

People with access to parks, trails, or tree-lined streets are far more likely to move their bodies. In fact, the presence of green spaces has been shown to triple the chances of meeting daily physical activity goals [4]. But this isn’t only about steps or exercise routines. It’s about designing cities where the healthier choice is also the easier, more enjoyable one.

When people move through green areas, they report higher levels of motivation and lower levels of stress. Physical activity in nature leads to improvements in cardiovascular health and mental resilience. It helps regulate mood, reduces anxiety, and creates a deeper sense of vitality and joy [5].

In green spaces, people don’t just move more—they feel better doing it.

Cooling the Concrete

As cities continue to densify, they become not only more crowded but also more dangerous. The phenomenon known as the Urban Heat Island (UHI) effect—where urban areas become significantly hotter than their rural surroundings—is now a major risk to human health. Cities can be up to eight degrees Celsius warmer than the landscapes they replaced.

Greenery is one of the most effective tools for mitigating this risk. Parks, green roofs, and tree canopy cover don’t just beautify cities—they actively cool them. Parks can reduce peak city temperatures by up to nine degrees Celsius. Green roofs can lower surface temperatures by as much as seventeen degrees [6].

The impact on public health is enormous. A study published in The Lancet found that increasing urban tree canopy coverage to 30% in European cities could prevent approximately one-third of premature deaths caused by extreme urban heat, equating to around 2,644 avoidable deaths annually. Enhancing tree cover by this amount could also lower urban temperatures by an average of 0.4°C, effectively mitigating the urban heat island effect [7].

Clean Air and Quiet Minds

Trees do more than provide shade. They clean the air. In urban environments, where respiratory illnesses are often fuelled by pollution from cars and industry, trees act as living filtration systems. They remove pollutants, absorb carbon, and refresh the oxygen we depend on.

In the United States, urban forests remove approximately 45 million tons of CO₂ annually—the equivalent of emissions from nearly 10 million cars [8]. These same forests also absorb fine particulate matter, lowering concentrations of harmful pollutants and improving overall air quality .

The presence of trees and plants also reduces noise pollution, dampens the intensity of crowds, and helps calm the overstimulation of city living. A walk through greenery can reduce cortisol levels—the hormone linked to chronic stress—and support long-term mental clarity [9]. When we speak of green infrastructure, we are speaking of an antidote to the psychological pressure of modern life.

Sunlight and Vitamin D Deficiency

As urbanisation increases, another problem has quietly reached global scale: Vitamin D deficiency. More than one billion people worldwide lack sufficient levels of this essential nutrient, and the design of cities is partly to blame [10].

High-rise buildings block natural light. Pollution reduces UV exposure. Long working hours indoors and screen-based leisure further limit access to daylight. On average, people now spend 90% of their lives indoors [11].