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Close-up: white fungal threads wrapping fine tree roots
Soil and life

Mycorrhiza

Terra Humana editorial teamLast updated: 2026-10-013 min read

Close-up: white fungal threads wrapping fine tree roots

In brief

The underground partnership between roots and fungi: the fungi reach water and phosphorus, the plant returns sugars and vitamins.

What is mycorrhiza?

Beneath a healthy forest lies a hidden partnership older than trees themselves. Mycorrhiza, from the Greek for "fungus-root", is the union of plant roots with specialised soil fungi. The fungi weave a fine network of threads, far thinner and far more far-reaching than any root, through the soil. They draw in water and nutrients such as phosphorus that the plant could never reach alone, and deliver them to the root. In exchange, the plant hands over a share of the sugars it makes from sunlight.

This is not a rare arrangement but the norm: the great majority of land plants, and almost all trees, live in partnership with mycorrhizal fungi. The network can even link many plants together underground, letting them share resources and signals: the living fabric that writers have called the "wood wide web".

For soil, mycorrhiza is a sign and a source of health. Where it flourishes, water and nutrients circulate; where the soil has been sterilised by heavy tillage or chemicals, it is lost, and plants struggle.

Fungus and root:,an underground partnershipLearning panel: mycorrhiza is the underground partnership between fungus and root. The fungal threads, far thinner and far more far-reaching than any root, deliver water and nutrients such as phosphorus that the plant could never reach alone. The plant hands over a share of the sugars it makes from sunlight. The great majority of land plants and almost all trees live in this partnership; the network can link many plants and let them share resources and signals, the “wood wide web”. Deep ploughing, synthetic fungicides and bare ground left to bake break the network. Minimal disturbance, permanent mulch and ground cover, and diverse plantings let it thrive. On dry ground, that fungal reach for water can decide whether a young tree survives its first summers. TERRAWIKI · LEARNING PANEL Fungus and root:an underground partnership Mycorrhiza, from the Greek for “fungus-root”. 1THE EXCHANGE sugars root fungal threads water phosphorus The fungus delivers water and nutrientssuch as phosphorusthat the plant couldnever reach alone The plant hands over a share of thesugars it makesfrom sunlight 2NOT A RARE ARRANGEMENT, THE NORM The great majority of land plants, and almostall trees, live in partnership withmycorrhizal fungi. “wood wide web”: sharing resources and signals 3HOW WE WORK THE LAND Breaks the network deep ploughingsynthetic fungicidesbare ground leftto bake Lets it thrive minimal disturbancepermanent mulchand ground coverdiverse plantings On dry ground, that fungal reach for water candecide whether a young tree survives itsfirst summers. Basis: Merlin Sheldrake, Entangled Life (2020) · TerraWiki: Mycorrhiza

How Terra Humana understands it

Terra Humana sees the soil not as a passive medium but as a living community, and mycorrhiza as one of its most important members. Restoration, in this view, is not only about the trees you can see but about rebuilding the invisible partnerships beneath them. A tree is only as healthy as the fungal network its roots can join.

This shapes how we work the land. Practices that tear the soil apart or poison its life (deep ploughing, synthetic fungicides, bare ground left to bake) break the mycorrhizal network. Gentle, covered, living soil lets it thrive. On dry ground especially, that fungal reach for water can decide whether a young tree survives its first summers.

Mycorrhiza in practice

At Sa Medada, near Jerzu, Terra Humana tends the soil in ways meant to keep its fungal life intact: minimal disturbance, permanent mulch and ground cover, and diverse plantings that give many fungi a home. Support species, compost and materials like charged biochar all help create the sheltered, living soil in which mycorrhiza flourishes.

This underground work is slow and largely unseen, but it is foundational. By protecting soil life rather than degrading it, Terra Humana gives the trees of Project Eden the best chance to establish on poor, dry ground, and gathers practical knowledge on how to bring a tired Mediterranean soil back to life.

The valley of Sa Medada near Jerzu, Sardinia, with olive grove and macchia
The valley of Sa Medada near Jerzu, Sardinia, with olive grove and macchia

Sa Medada

What this looks like at Sa Medada

How dense the fungal network in the soil of Sa Medada already is, we do not yet know: a laboratory analysis is outstanding, and no soil pH has been measured so far. Until there are values, the simplest principle applies. We keep the ground covered and shaded and dig as little as possible, because digging is exactly what tears the fungal threads.

More about Project Eden

Frequently asked

What is mycorrhiza?

Mycorrhiza is a partnership between plant roots and certain soil fungi. The fungi grow a vast, thread-like network through the soil, reaching water and nutrients far beyond what the roots alone could access, and pass much of it to the plant. In return the plant shares the sugars it makes from sunlight. Most plants on earth, the great majority of trees among them, depend on this partnership.

Why does mycorrhiza matter for Terra Humana?

In dry Mediterranean soil, the fungal network greatly extends a tree's access to scarce water and helps it establish. Healthy mycorrhiza can be the difference between a struggling sapling and a thriving one. Terra Humana works to protect and encourage this soil life, avoiding practices that destroy it, as a foundation of restoration at Sa Medada.

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Related terms

Mentioned in

See this in practice

Sources

  • PNAS, Climate mismatches with ectomycorrhizal fungi and tree range shifts
  • Nature Communications, Mycorrhizal colonization of dryland tree establishment
  • Merlin Sheldrake, Entangled Life (2020)

Last updated: 2026-10-01