Tropical forests in Borneo are home to organisms that produce their own light, but the phrase “bioluminescent forest” can create a misleading impression. The entire landscape does not light up like something from a science-fiction film. The light usually appears in small points: on mushroom caps, their stems, mycelium running through dead wood or the bark of a tree.
One documented case comes from Sepilok, in the state of Sabah, on the Malaysian part of the island of Borneo. In a taxonomic study published in 2010, researchers described Mycena silvaelucens, a tiny mushroom found on the bark of a tree in dipterocarp forest. The mushroom’s cap, gills and especially its stem emitted yellowish-green light. The specimens had caps just 4–18 millimetres in diameter—an essential detail for understanding the true scale of the spectacle.
What really “glows” in Borneo
In the case of Mycena silvaelucens, researchers found the mushrooms in groups on the bark of a dipterocarp tree in a lowland forest. The species was collected on 12 December 2007 along the Mangrove Trail in the Sepilok Orangutan Rehabilitation Centre area. The study specifies that, at the time, it was known only from the type specimen—the specimen on which it was formally described to science.
So, there is strong confirmation that luminous mushrooms grow in Borneo. But this does not show that every forest on the island offers an intensely green landscape night after night. Borneo has very different ecosystems, and the appearance of fungal fruiting bodies depends on the substrate, moisture, the condition of the wood and the life cycle of each species.
Another study examined luminous wood collected in Borneo at the end of 2013. The authors observed mycelium that continued to emit light under laboratory conditions for several months. However, they did not identify the fungus involved with certainty and found no fruiting bodies in the wild. It is a good example of how incompletely documented the diversity of luminous fungi remains: light may be observed before the organism producing it has been rigorously named.
Why images can look more spectacular than direct viewing
Viral photographs of “neon forests” should be viewed carefully, rather than automatically dismissed. They may show a real phenomenon, but photographic technique greatly changes the impression of intensity. In the paper on Mycena silvaelucens, images of the luminous mushrooms were taken with exposures of 90–120 seconds, and in other cases with exposures of as much as 480–720 seconds. A camera therefore allows faint light to accumulate on the sensor for far longer than the human eye does in an ordinary glance.
For more science information, you can also read Why are wombat droppings cube-shaped? The mystery explained by anatomy and physics, where you can find complementary details on this subject.
The result can be very beautiful and useful for research, because it makes the distribution of light across the mushroom’s parts visible. But a long-exposure photograph is not equivalent to an instant view. In a real forest, a dark-adapted eye may perceive some specimens as discrete yellowish-green points or patches, not necessarily as light bright enough to guide the way.
There is another common confusion: bioluminescence is not the same as fluorescence. A fluorescent object becomes visible after being illuminated by a suitable external source, such as ultraviolet light. A bioluminescent mushroom produces light through its own chemical activity. It does not need a UV torch to emit light, although ultraviolet light or other factors may alter the observed intensity in certain experiments.
The chemical reaction behind the green light
Fungal bioluminescence is a biochemical reaction. In simplified form, a molecule called luciferin is oxidised with the help of oxygen and the enzyme luciferase; some of the energy released appears as light. Modern research has identified the luciferin 3-hydroxyhispidin and the key enzymes that produce and transform it in this fungal system.
Importantly, this mechanism is not a separate “battery”, but is linked to the mushroom’s metabolism. Without oxygen and the energy needed for cellular reactions, light emission cannot continue. The light should therefore not be seen as a permanent decorative property of a species, but as the result of a living organism at a particular stage of growth and under particular environmental conditions.
In Mycena silvaelucens, the light was described as yellowish-green, and the stem was more intensely luminous than the cap and gills. This distribution again shows why a photograph of a colony can suggest a “lit-up” trunk, even though the source consists of several small fruiting bodies or mycelial threads, rather than the wood itself.
What purpose does glowing serve for a mushroom?
The certain answer is that we do not yet know for every species. The hypothesis with the strongest experimental support concerns spore dispersal. Mushrooms cannot move; to colonise a new log, branch or another damp area, they must spread their spores.
An experiment involving a luminous mushroom from Brazil, Neonothopanus gardneri, showed that nocturnal emission controlled by the circadian rhythm can attract arthropods. The researchers also used artificial LED-lit mushrooms, precisely to separate the effect of light from other signals such as scent. The conclusion was that light may increase the chance that insects notice the mushroom in the dark, which could help transport spores.
However, this result should not automatically be applied to all mushrooms in Borneo. A biologically plausible explanation for one species does not become a universal certainty. In the case of Mycena silvaelucens, the species-description study confirms its luminescence and habitat, but does not yet demonstrate the specific ecological role of its light.
Why Borneo matters to this story
Borneo’s dipterocarp forests are extremely complex systems, with abundant dead wood, high humidity and fungal diversity that has not been sufficiently surveyed. A genomic study carried out in two conservation areas in Sabah found numerous fungal sequences that were not represented in public databases. This does not mean that all these fungi are luminous, but it shows just how large the still-unknown share of local fungal biodiversity is.
In this context, a luminous mushroom is not merely a curiosity that photographs well. It is also an indicator of a broader biological network: decaying wood, microorganisms, insects and trees together form an ecosystem in which matter is continuously recycled. Fungi break down plant material and recover nutrients that become available again in the forest.
What we can say without exaggerating
| Claim | What the evidence shows |
|---|---|
| “There are bioluminescent mushrooms in Borneo.” | Yes. Mycena silvaelucens was described from Sepilok, Sabah, and other research has examined luminous wood collected in Borneo. |
| “The whole forest in Borneo glows.” | No. Light is produced locally by small organisms, not by all vegetation or the forest canopy. |
| “The neon photographs are fake.” | Not necessarily. The phenomenon can be real, but long exposures make faint light much more visible and more intense in an image. |
| “It is known exactly why all mushrooms glow.” | No. Arthropod attraction for spore dispersal has experimental support for some species, but the role differs or remains unclear in many cases. |
Borneo’s forests do not need the legend of a uniformly glowing jungle to be remarkable. The verifiable fact is more subtle: on bark, on decaying wood and sometimes in strands of mycelium, organisms just a few millimetres across can turn chemical energy into green light. Viewed correctly, the phenomenon is no less spectacular, but easier to understand.
Bioluminescence also recalls a useful rule for spectacular images of nature: before asking whether they are “real”, it is worth asking exactly what they depict, at what scale and using what technique.
Frequently asked questions
Are there really mushrooms that glow in Borneo?
Yes. One documented example is Mycena silvaelucens, a species described from Sepilok, Sabah, whose cap, gills and stem emit yellowish-green light.
Does the forest in Borneo glow all night?
No. The popular label can be misleading. The phenomenon is local and is produced by mushrooms or mycelium, not by the entire forest.
Why do glowing mushrooms look so bright in photographs?
Long-exposure photographs accumulate faint light on the sensor for tens of seconds or minutes. As a result, the luminescence appears more intense than it does at a quick glance.
Are glowing mushrooms fluorescent?
Not necessarily. Bioluminescence is light produced by a chemical reaction within the organism itself; fluorescence requires excitation by an external light source.
