16 May 2025 | Article

The Underground Network

Wolves helping the forest, and salmon climbing trees — how is that possible? The answer lies in a hidden world beneath our feet — in the extraordinary symbiosis between fungi and the plant kingdom, known as mycorrhiza.

Fungal spores lying dormant in the soil spring to life when they come into contact with a plant’s roots. They penetrate the root system and receive carbohydrates from the plant. In exchange, the fungi assist the plant in absorbing water and essential nutrients.

This mutual relationship deepens as the fungi grow thread-like structures called hyphae, which extend from the roots and branch out into complex underground networks known as mycelium. These delicate threads weave through the soil in search of nutrients, acting like an extension of the plant’s own root system. Many common edible mushrooms — such as boletes, russulas, and chanterelles — are mycorrhizal fungi.

Plants and mycorrhizal fungi have coexisted and co-evolved for over 400 million years — virtually since plants first appeared on Earth. But when forests are clear-cut, about three-quarters of the soil’s mycorrhizal species disappear. We still don’t know how long it takes for such a network to recover — or if it even can.

So how can wolves help forests? And what about salmon climbing trees? If you’re curious and want to dive deeper into these fascinating connections in nature, read Naturens dolda nätverk (original title Das geheime Netzwerk der Natur) by Peter Wohlleben. Published in 2017, the book offers a compelling and accessible explanation of the complex web of life that keeps ecosystems thriving.

Highly recommended reading!

Photo: fightCOtwo