Accessibility Tools


UV protection for forests

Ultraviolet rays reveal both the hidden wonders and sufferings of plants

Marta Abbà
a story by
Marta Abbà
UV protection for forests

The climate crisis breaks the balance between UV radiations and forests: the effects UV radiation on forests are subtle but significant, as biologist Paul Barnes emphasizes the urgency of monitoring their surface and health. David Atthowe contributes to this effort by photographing forests using biofluorescence techniques, revealing the beauty of even the most common plants and reminding us of the need to protect them all

Climate, ultraviolet rays and plants have always interacted in a sort of magical three-way dance that takes place between heaven and earth—a dance only nature can perform when allowed to evolve naturally. This dance has been violently interrupted by the climate crisis, which is now forcing the world’s forests to “learn new steps”, new ways of surviving a phenomenon triggered by those who cross them as trekkers, tourists or, at best, native inhabitants. Humans.

How UV radiation affects forests

If one takes a quick look at the entire solar spectrum, UV radiation might almost be overlooked. In the electromagnetic spectrum representing the different radiation frequencies, UV rays lie between X-rays and visible radiation. Despite their relatively small wavelength range (10-400 nm), UV rays significantly impact plant life.

Forests, delicate pivots in the global carbon cycle, and crucial natural carbon pools are at risk of being disturbed by variations in solar UV radiation. This ongoing phenomenon is invisible and slow but inexorable.

The “minor” effects of UV radiation affect plant growth and development, starting with flavonoids1, which also play a defensive role against herbivores and pathogens. Environmental biologist Paul Barnes has always paid close attention to even the smallest signals that indicate the health of the Earth. He studies the interactions between light and ecosystems and explains:

UV rays can affect the shape of plants and their leaves, limiting their growth and altering the competitive relationships between different plant species.

This means that entire ecosystems must find a new balance, rearranging themselves to survive, which strongly impacts individual plant and animal species. Forests provide nourishment for many creatures that may not be ready to change their diet and may be forced to migrate.

Paul W. Barnes is a professor of environmental biology at Loyola University in New Orleans. After a PhD at the University of Nebraska and a post-doc at Utah State University, he taught at Loyola, St. Olaf College and Texas State University, leading the Environmental Protection Agency’s (EPA) Environmental Research Laboratory. As an ecologist and physiologist, he examines the response of plants and ecosystems to global environmental changes. His research has been funded by the National Science Foundation, US Department of Agriculture, NASA, EPA and various state and local agencies. He has published more than 200 papers and has advised NSF (National Science Foundation), USDA United States Department of Agriculture, EPA, the National Academy of Sciences and the EU COST programme. He currently co-chairs the United Nations Environment Programme’s Environmental Effects Assessment Group and teaches courses in botany, ecology and environmental science at Loyola University.

«The greatest risk from UV radiation that forests face lies in the reduction of photosynthesis and productivity», Barnes explains. He further points out that «such extreme levels have been largely avoided so far thanks to the Montreal Protocol2».

Effective in 1989 to regulate ozone-depleting chemicals, this international agreement has so far contributed to the elimination of 99% of such chemicals, like chlorofluorocarbons (CFCs). Their continued and uncontrolled use would have pushed global temperatures up by one degree Celsius by mid-century. Thanks to the Montreal Protocol, however, the ozone hole has almost completely recovered by 2023. It could possibly close globally by 2050 in central zones3, by 2045 in the Arctic, and by 2066 in Antarctica.

Moving from fears for the future of the world’s forests «irradiated by UV wavelengths», we can take comfort in the effectiveness of international agreements like the Montreal Protocol. The Montreal Protocol is in fact an example of how agreed and shared actions can positively impact our planet’s future, even if they result from compromises, necessary to bring together diverse interests. The forests saved so far and the avoided temperature rise are evident and measurable evidence of this.

What we risked and what is left to do

The awareness that we have avoided serious effects, according to Barnes, should not lead us to consider the “UV danger” averted. «We must always keep in mind the risks we may still face. According to one of the few recent modeling studies available, the extreme levels of ultraviolet-B radiation (290-315 nm) that would have occurred without the Montreal Protocol would have reduced photosynthesis and plant growth globally, consequently decreasing the amount of carbon stored by terrestrial vegetation» Barnes explains. «By the end of this century, we would have recorded an increase of 115-235 parts per million of carbon dioxide in the atmosphere and a 0.5-1.0 °C rise in average surface temperature, with peaks exceeding 1.0 °C in the Arctic».

This should not frighten us but rather guide our priorities in strategic choices on both local and global scales.

The reduction of greenhouse gas emissions and the protection of the biosphere remain essential for maintaining the health and biological diversity of forests and other terrestrial ecosystems.

Barnes continues «It is essential to continue monitoring global forest cover and photosynthesis. In fact, this monitoring needs to be expanded to quantify the productivity and species composition of forest communities».

Changing wavelengths thanks to UV rays

Exploring possible futures with UV rays highlights how international agreements like the Montreal Protocol can be decisive in shaping the evolution of the entire Earth’s ecosystem. The same wavelengths, when introduced within forests, reveal «their fluorescent secrets waiting to be unveiled».

David Atthowe has led expeditions to rainforests around the world and has had the chance to live with many indigenous tribes. He is the director of Reveal Nature, a company that offers nature connection experiences that show its hidden sides. He has spent more than 500 hours in the field exploring biofluorescence around the world, making many discoveries new to science. He is also the founder of Nomadic Lion, an organisation that has walked more than 10,000 km in 5 different countries to share happiness and joy with everyone.

Discover more

This is how David Atthowe, an explorer, photographer, and forest therapist from England, describes it. He uses ultraviolet radiation to discover, showcase, and capture «the fascinating and invisible aspects of pretty common plants that we would normally overlook», he explains.

Atthowe aims to amaze and encourage people to find «reasons for wonder in the everyday», showing them that beauty exists even if it’s not always immediately visible. Sometimes, one needs to change wavelengths to realize the beauty surrounding us. Sometimes, it requires a change in perspective.

«In Norfolk, England, for example, we have many nettles that are ignored by everyone but at night, under UV light, they can display four different colors depending on their health and position».

Seeing a nettle glow red or bright blue certainly makes it appear much more special, but Atthowe’s work is much more than a play of lights and wonder in the woods. It is a way to raise awareness, encouraging people to take care of every corner of the planet. As an explorer and photographer, he does this by feeding beauty to those who trust him and spend a few hours of their time with beauty.

«We are living through a period of mass extinction of many important species; it is crucial to document as much biofluorescence as possible», he explains. «It is a widespread characteristic and allows us to learn a lot about the health of plants». Many fungal infections, for example, exhibit evident fluorescence, while other plants release a fluorescent defensive sap after being damaged by herbivores. These are all interesting signs for those who wish to preserve today’s endangered biodiversity».

David Atthowe’s biofluorescent photos

The world of biofluorescence immediately captivated this explorer and photographer, revealing to him «a vibrant world of colours, invisible to the naked eye, that I immediately wanted to share with as many people as possible» he explains. This impulsive urge of his turned into the Reveal Nature project and a series of night walks and guided expeditions to explore new habitats with biofluorescence.

Biofluorescence is the phenomenon whereby a living organism, such as a plant, absorbs light at a non-visible wavelength, such as UV, and re-emits it at the visible spectrum.

«I have been a photography enthusiast for a long time and was thrilled when I realised that it was possible to capture in pictures the same magic that my eyes saw» explains Atthowe. «What our eyes can see, can also always be photographed: we are documenting and exploring biofluorescence in a wide range of habitats around the world. This year we are focusing in particular on documenting fluorescence in temperate rainforests. Those in the UK, where we started, are home to the largest concentration of oceanic lichens and mosses in Europe. They are fascinating subjects, some even glowing in different colors depending on the section observed».

Atthowe’s biofluorescent explorations are a continuous discovery of unsuspected, as well as invisible, wonders. «There’s the “glittering wood moss” that turns the tips of some branches golden, other mosses are starry and reddish-brown, intertwining with the blue fronds of the rare Tunbridge fern, and they shine when covered in raindrops» he says and takes pictures, to show those who have not yet tried to look at the world through UV filters what they are missing. And what we all risk compromising forever by disturbing the balance of forests, even those just steps away from our cities.

Series of shots by photographer David Atthowe for the Reveal Nature project, in order: (image 1) Biofluorescence in forests, branch detail (image 2) Biofluorescence in forests, leaf detail (image 3) Biofluorescence in forests, moss and lichen detail (image 4) Biofluorescence in forests, leaf detail All rights reserved. Reproduced with permission of the author.

The world’s forests under UV rays

This is why Atthowe began his experiments in “his” Great Britain. «UV rays make some of its forests resemble a Western version of a tropical coral reef, displaying a riot of colors with surprising branched structures, patterns, and relationships that secretly connect all forms of life» he explains, foreshadowing what can be admired during guided biofluorescent night walks which have seen the participation of around 1,000 people over the years.

After his experiences in India, Malaysia and Indonesia, this explorer has no intention of staying on his home island.  He has already completed a nine-week tour of the Borneo areas, which has just ended, where he also discovered how Nepenthes rafflesiana4 has four different colours of fluorescence: pink, purple, yellow and blue. «A study that took place at the Jawaharlal Nehru Tropical Botanic Garden and Research Institute in India5 showed how this phenomenon serves as a lure to attract prey» he explains enthusiastically at the mere recollection of the image he saw.

Later this year, he plans to travel to Chile, to explore the rainforest of the Maldive Islands, and within the next 5 years also explore Mexico, Colombia, Ecuador, India, Madagascar and Kenya through biofluorescence. All these journeys require a certain spirit of adventure but not specific equipment: «UV flashlights are enough» Atthowe notes. It is our minds that need to be “equipped”—to be willing to stop and notice the less obvious beauty that, with different wavelengths, shines and reveals a precious everyday reality. This is a reality everyone has the duty to protect and the pleasure to admire, with or without UV rays.


  1. For more on the nature of flavonoids see Centorrino F. (2021). I flavonoidi: caratteristiche, struttura e proprietà, Microbiologia Italia. ↩︎
  2. On the Montreal Protocol, ratified by 197 countries in 1988, see,consumo%20di%20sostanze%20ozono%20lesive ↩︎
  3. On the recent news of the possible closure of the ozone hole by mid-century see World Meteorological Organization (2022). Executive summary. Scientific assessment of ozone depletion: 2022, WMO, GAW Report No. 278, pp 56, Geneva. ↩︎
  4. On Nepenthes rafflesiana see ↩︎
  5. For more on the phenomenon studied at the Jawaharlal Nehru Tropical Botanic Garden and Research Institute see Baby, S., Johnson, A. J., Zachariah, E. J., & Hussain, A. A. (2017). Nepenthes pitchers are CO2-enriched cavities, emit CO2 to attract preys. Scientific Reports7(1). ↩︎


Where culture branches out and evolves

Sign up to receive our free newsletter every Saturday