Ipsa Tripathy
Bhubaneswar: Walk through any forest, and it is easy to believe that every tree stands alone. Each one appears to compete for sunlight, water, and space. Their roots disappear into the soil, hidden from view, while their branches stretch independently towards the sky. For centuries, forests were understood as collections of individual trees competing for survival. Modern science has revealed a very different story.
Beneath every healthy forest lies an extraordinary underground network, one that is invisible to the human eye yet essential for the functioning of entire ecosystems. Trees are not isolated organisms. They are connected through vast networks of microscopic fungi that transport nutrients, water, and chemical signals from one plant to another. Scientists refer to this phenomenon as the mycorrhizal network, often described as the “Wood Wide Web” or the underground internet of forests.
Although the comparison to the internet is symbolic, it captures an important idea: forests are connected systems where information and resources can move through living networks beneath the soil. Understanding this hidden world is transforming the way scientists think about forests, biodiversity, and conservation.
More Than Just Tree Roots
A forest is much more than the trees we see above the ground. Beneath the soil exists an enormous community of fungi, bacteria, insects, earthworms, roots and microorganisms, all interacting continuously. Among these organisms, mycorrhizal fungi play one of the most important roles. The word mycorrhiza comes from the Greek words mykes (fungus) and rhiza (root), meaning “fungus-root.”
These fungi form mutually beneficial relationships with the roots of most terrestrial plants. The fungi grow as extremely fine thread-like structures called hyphae, extending far beyond the reach of plant roots. Together, these microscopic threads form an extensive underground network known as the mycelium.
This network dramatically increases the area through which plants can absorb water and essential nutrients such as phosphorus and nitrogen. In return, the plants provide the fungi with carbohydrates produced through photosynthesis. It is one of nature’s oldest and most successful partnerships, having evolved over hundreds of millions of years.
Nature’s Communication Network
The importance of these fungal networks extends beyond nutrient exchange. Over the past few decades, ecological research has shown that mycorrhizal networks can also facilitate the movement of chemical compounds between connected plants. Under certain conditions, carbon, nutrients and signalling molecules have been observed moving through these fungal pathways.
When one plant experiences stress, such as insect attack or disease, chemical signals may travel through the underground network to neighbouring plants. These signals can trigger defensive responses before the threat reaches them. Researchers have demonstrated this phenomenon in controlled experiments involving several tree species, although the complexity of these interactions continues to be an active area of scientific research.
Scientists are still investigating exactly how widespread and influential these communication processes are across different forest ecosystems. What is increasingly clear, however, is that forests function less like collections of individual trees and more like interconnected biological communities.
Sharing Resources During Difficult Times
One of the most remarkable discoveries concerns the movement of carbon between trees. In mature forests, larger trees can transfer carbon compounds through fungal networks to younger seedlings growing in deep shade where photosynthesis is limited. This does not happen because trees “choose” to help one another in a conscious sense. Rather, the interconnected fungal network allows resources to move between plants under certain ecological conditions.
Such exchanges may improve the survival of young seedlings during their early stages of growth, contributing to the long-term stability of forest ecosystems. Scientists have also observed resource movement between different plant species connected by compatible fungal networks. These findings suggest that forests possess levels of ecological cooperation that were largely unrecognised until recent decades.
The Importance of “Mother Trees”
Forest ecologists have introduced the concept of mother trees to describe large, mature trees that occupy central positions within underground mycorrhizal networks. Because of their extensive root systems and long-established fungal associations, these trees are often connected to many younger individuals nearby.
Research has shown that mature trees play a significant role in supporting forest regeneration by maintaining stable fungal networks and contributing carbon to surrounding seedlings. When these older trees are removed through logging or land clearing, the underground network can also become fragmented.
The loss is therefore greater than the removal of a single tree. It may disrupt an entire ecological system that has developed over many decades. This understanding is changing approaches to sustainable forest management around the world.
Forests Depend on More Than Trees
The underground internet of forests reminds us that biodiversity extends far beyond visible wildlife. Fungi are neither plants nor animals. They represent their own biological kingdom and perform functions that few other organisms can replace. Without them, nutrient cycling slows, plant growth declines, and forests become less resilient to environmental stress.
Healthy soils rich in fungal diversity also improve water retention, reduce erosion, and support carbon storage. In many ways, fungi serve as the engineers of forest ecosystems. Yet they remain among the least understood components of biodiversity.
Climate Change and Underground Networks
Climate change introduces new challenges for these hidden ecosystems. Increasing temperatures, prolonged droughts, altered rainfall patterns and more frequent wildfires can affect both fungi and the trees that depend on them. Drought reduces soil moisture, limiting fungal growth and weakening the exchange of water and nutrients.
Intense wildfires can destroy surface vegetation while also damaging underground fungal communities that may take years to recover. Deforestation presents another serious threat. When forests are fragmented by roads, mining, urban expansion or agriculture, the underground networks are fragmented as well.
Planting new trees alone cannot immediately restore these complex biological relationships. Developing healthy mycorrhizal communities often requires decades of ecological recovery. This is one reason why scientists emphasise protecting old-growth forests rather than relying solely on tree-planting programmes.
Rethinking Forest Conservation
The discovery of mycorrhizal networks is reshaping conservation science. Traditionally, forest management focused primarily on visible components such as tree density, timber production and wildlife populations. Today, ecologists recognise that healthy forests depend equally on what lies beneath the surface.
Conservation therefore involves protecting entire ecosystems, including soils, fungi, microorganisms, wetlands and natural processes, not simply preserving trees. This perspective also changes how ecological restoration is approached. Restoring degraded forests requires rebuilding living soil communities alongside vegetation. Without healthy underground biodiversity, newly planted forests may struggle to achieve the resilience of natural ecosystems.
Lessons for India
India’s forests, from the Himalayan temperate forests to the Western Ghats, Central Indian forests and the tropical forests of Odisha, support an extraordinary diversity of fungi, plants and wildlife. Although research on Indian mycorrhizal networks is still expanding, scientists recognise their importance in maintaining forest productivity, nutrient cycling and ecosystem stability.
For states like Odisha, where forests support elephants, tigers, pangolins and countless other species, protecting underground biodiversity is inseparable from protecting wildlife above the ground. Every mining project, road expansion or large-scale deforestation affects more than visible vegetation. It also influences the invisible ecological relationships that sustain forests over generations.
A Forest Is a Living Community
The greatest lesson from the underground internet of forests is surprisingly simple. Nature is built on connections. For centuries, humans viewed forests as collections of individual trees competing against one another. Science now paints a more sophisticated picture. Forests are living communities connected by intricate networks that recycle nutrients, support regeneration and strengthen ecological resilience.
This hidden world reminds us that the health of a forest cannot be measured only by the number of trees standing above the ground. Its true strength also lies beneath our feet, in billions of microscopic fungal threads quietly linking life together. As humanity faces climate change, biodiversity loss and increasing pressure on natural ecosystems, protecting forests means protecting every layer of life they contain, both visible and invisible.
Because the future of a forest does not depend solely on the trees we can see. It also depends on the extraordinary network that has been silently keeping them connected for millions of years.