Shades of Green

Last month, I mentioned the remarkable transformation soon to take place around Loch Sunart, as the ancient Atlantic oakwood prepared to unfurl its fresh spring leaves. Now, that change is fully in motion. The once bare woodlands have come alive, and the hillsides surrounding the loch are now blanketed in a rich tapestry of green, with countless verdant shades blending to create a vibrant and beautiful scene. Our eyes are especially tuned to this display – of all the colours in the spectrum, we can see more shades of green than any other. It is also a colour that helps us feel more at peace and connected to nature.

Verdant Canopy - Phemie’s Walk, Strontian, Sunart

​To understand why our eyes are so adept at detecting and differentiating so many shades of green, it’s important to examine the underlying biology of our visual system.
 
The human retina contains three types of cone cells, each designed to detect specific light wavelengths. These cones are known as short (S), medium (M), and long (L) wavelength cones, which are most sensitive to blue, green, and red light, respectively.
 
All three types of cones work together to help us see a wide spectrum of millions of colours. However, the medium-wavelength cones, which are sensitive to green, are the most abundant and the most responsive. This increased sensitivity lets us distinguish a broad range of green shades with remarkable precision.
 
The biological emphasis on green detection is not coincidental. It’s an evolutionary trait. Our primate ancestors depended on their vision for survival in dense, green environments. Being able to detect the subtle differences between green hues helped them find edible plants, spot hidden predators, move through tricky terrain, and locate water. Those who were better at it had a higher chance of survival and passed this skill on to future generations.
 
As a result, our eyes can detect even the slightest variations in green hues, allowing us to recognise a wider range of green shades more easily and accurately than any other colour in the visible spectrum. This is also why the greens of spring appear so vibrant and diverse to us.
 
Our ability to detect so many shades of green not only affects how we see the natural world but also plays a key role in our psychological and emotional well-being. Since green is the colour most frequently processed by our eyes, it often feels calming and relaxing. Our brains can interpret green with little effort, making it one of the most soothing colours for the human eye.
 
Psychologically, green is often associated with balance, harmony, and renewal. These associations are deeply rooted in our evolutionary past, when seeing green likely signalled safety, abundance, and the presence of life-sustaining resources like water and vegetation. Today, green still brings a sense of calm and comfort and this is why it’s commonly used in certain environments to reduce stress, such as hospitals, schools, and workspaces.
 
Furthermore, spending time around green spaces – especially natural greens found in plants and outdoor areas – can help reduce anxiety, lower blood pressure, and improve concentration. This effect, known as “biophilia”, reflects our natural bond with nature and the calming power of green environments. Even artificial exposure, like viewing forest images or using green in interior design, can create a sense of calm and support mental recovery.
 
In summary, our natural sensitivity to green doesn’t just help us see the world more clearly – it helps us feel better while doing so. Green gives us both visual comfort and emotional calm, helping us feel more at peace and more connected to nature.

Sanctuary - Phemie’s Walk, Strontian, Sunart