How trees communicate underground: the mycorrhizal network

How trees communicate underground: the subterranean language of the forest

Imagine a forest—a green sea of trees reaching for the sky, yet the real life unfolds beneath their roots. In the darkness of the soil, an astonishing story of interaction, support, and communication takes place. This story is about mycorrhiza—the symbiosis between fungi and plant roots that creates an underground network connecting the entire forest.

What is mycorrhiza: the amazing alliance of fungi and roots

Mycorrhiza represents a mutually beneficial partnership between fungi and plant roots. Fungi receive carbohydrates from plants, which are essential for their growth, while in return, they help absorb water and nutrients from the soil. This symbiosis is so effective that most plants in nature cannot survive without it.

Although it may seem like something out of science fiction, mycorrhiza has existed for hundreds of millions of years. Even before the first flowering plants appeared, fungi and plants had established a collaboration that continues to function more effectively than any modern contract.

How the mycorrhizal network works: the forest internet

Fungal hyphae, which are microscopic threads, wrap around tree roots, forming an additional invisible root system. They penetrate the soil much farther than the tree roots themselves and act like the internet. These threads transmit nutrients, water, and chemical signals. Through mycorrhiza, trees can exchange information about water shortages, pest attacks, and changes in the soil.

There have been recorded instances where trees of the same species, on the brink of death, transfer their resources to neighboring plants, which can be seen as a final gesture of support. Young saplings, unable to independently obtain enough nutrients, receive help from mature trees through the fungal network. This has been confirmed by experiments conducted, for example, in the forests of British Columbia.

Mother trees: the heart of the underground forest

In every healthy forest, there are so-called “mother trees”—the oldest and most majestic trees that play a key role in supporting young plants. These trees have the most developed mycorrhizal networks and actively “communicate” with each other, coordinating underground life. They transfer nutrients, including carbon, to other trees in need.

Mycorrhiza and ecology: how the fungal network protects the forest

Mycorrhiza not only contributes to the well-being of individual trees but also supports entire ecosystems. In forest conditions prone to drought, the mycorrhizal network helps retain moisture more effectively. Soil containing mycelium holds nutrients better, allowing plants to suffer less from diseases and recover more quickly from damage.

The role of mycorrhiza in adapting to climate change

In today’s world, where climate change is becoming increasingly pronounced, mycorrhiza also serves a protective function. It aids in the better adaptation of forests to new conditions. Thanks to mycorrhiza, trees respond more quickly to changes in temperature, moisture levels, and soil acidity.

Moreover, mycorrhiza facilitates the absorption of carbon from the atmosphere. Fungi can sequester carbon, which slows down the greenhouse effect. Thus, what is hidden underground literally saves us from above.

Types of mycorrhiza: a distinction among fungi

Mycorrhiza encompasses various forms, with the two principal types being ectomycorrhiza and endomycorrhiza. Ectomycorrhiza develops a sheath around the root without infiltrating the cells, whereas endomycorrhiza penetrates the root cells themselves. Distinct tree species establish symbiotic relationships with different fungal species; for instance, pines and spruces engage with ectomycorrhizal fungi, while grains and grasses typically associate with endomycorrhiza.
Notably, fungi exhibit a degree of selectivity—some species form exclusive partnerships with specific tree species, while others are generalists, capable of associating with a variety of tree genera. This phenomenon fosters the development of extensive underground communities.

Urban trees and mycorrhiza: isolation amidst concrete

In urban settings, trees frequently encounter isolation due to the presence of asphalt, concrete, compacted soil, and aggressive land management practices, which impede the establishment of typical mycorrhizal relationships. Consequently, this limitation restricts underground communication, rendering urban trees more susceptible to vulnerabilities, increasing their likelihood of disease, and shortening their lifespan.
Nevertheless, when provided with suitable conditions—such as being planted in living soil, in proximity to other trees, and with minimal chemical intervention—these trees can initiate the formation of their mycorrhizal networks. This prospect offers hope for the cultivation of more vibrant and resilient urban environments.

Threats to mycorrhiza: emerging challenges for the subterranean ecosystem

In contemporary times, mycorrhiza confronts a multitude of threats, prominently including urbanization and the adverse effects of chemicals such as pesticides, herbicides, and excessive nitrogen fertilizers. Furthermore, deforestation, soil compaction, and alterations in soil acidity also detrimentally impact fungal networks. The degradation of mycorrhiza precipitates the collapse of entire ecosystems.
In forests where mycorrhiza has been preserved, recovery following natural disasters, such as wildfires or hurricanes, occurs at a markedly accelerated rate. Thus, safeguarding this subterranean ecosystem is as crucial as the protection of wildlife and the combat against illegal logging.

Mycorrhiza in agriculture: future prospects

It is noteworthy that mycorrhiza is increasingly being integrated into agricultural practices. Specialized formulations containing mycorrhizal fungi facilitate successful plant growth in nutrient-deficient soils, diminish the reliance on fertilizers, and enhance crop yields. While this is not a panacea, it signifies a progressive step towards more sustainable agricultural methodologies.

A hidden world beneath our feet

Mycorrhiza represents more than merely a fungus coexisting with a plant’s root; it constitutes a complex ecosystem that breathes, responds, assists, and interacts. This realm, though largely imperceptible to the majority, plays a pivotal role in sustaining forests, fields, climate, and ultimately, human existence.
Should you find yourself wandering through a forest in the future and feel compelled to pause by an ancient oak, do not disregard this impulse. Beneath it may lie a network that sustains life within the forest—a living entity that harbors memories.

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