Beneath every Czech forest lies a mysterious network that scientists call the mycorrhizal network – and journalists have nicknamed the internet of the forest. Through fine fungal threads, trees share nutrients, water and even warnings about pests. Test how well you know this underground communication and read our guide to the symbiosis of trees and mycelium in Czech forests.
🌲 Quiz: Trees and mycelium – the internet of the forest
Choose a difficulty and find out how deep your knowledge of the forest's underground world goes. The quiz has 10 questions with 4 possible answers and an educational fact after each one.
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Visit AMADEAA guide to the mycorrhizal network of Czech forests
Forests are not just a collection of trees – they are interconnected organisms, and the key to their cooperation is fungi. Mycorrhizal threads (mycelium) grow through the soil and link the roots of dozens, sometimes hundreds of trees in a network that scientists compare to the internet. Understanding this network means understanding why Czech beech, spruce and oak forests are so resilient – or, on the contrary, so vulnerable.
The mycorrhizal network (symbiosis of fungus and root)
Mycorrhiza (from the Greek mykés = fungus, rhiza = root) is a symbiotic relationship in which a fungus wraps a tree's fine roots in a dense mesh of threads called mycelium. The tree supplies the fungus with sugars made by photosynthesis, and the fungus pays it back with minerals – especially phosphorus and nitrogen – and water, which its thin threads draw from the tiniest soil pores that the root itself cannot reach. The relationship is so beneficial to both sides that practically all forest trees in Central Europe take part in it.
Two main types of mycorrhiza meet in Czech forests. Ectomycorrhiza wraps the fine roots from outside and is typical of beech, oak, spruce, pine and fir – in other words, the vast majority of forest stands in the Šumava, the Ore Mountains and the Bohemian-Moravian Highlands. Arbuscular mycorrhiza grows directly into root cells and dominates in grasslands and tropical forests. It is the ectomycorrhizal fungi that produce the beautiful fruiting bodies we see in the forest – boletes, chanterelles, milk caps and amanitas.
Penny bun (Boletus edulis)
The penny bun (also known as the cep or porcini) is the most prestigious mycorrhizal partner in Czech forests. It forms ectomycorrhiza mainly with spruce, beech and fir in mixed stands from the lowlands up to the foothills at around 1,200 m above sea level in the Krkonoše and Šumava mountains. Penny bun mycelium can link hundreds of trees over an area of up to several hectares and move carbon from sunlit trees to their shaded neighbours.
The fruiting body – the part we see and pick – is only a fraction of the fungus's total biomass. The underground mycelium is permanent and can survive for decades. That is exactly why mushroom spots are so reliable: where a penny bun grew this year, it is very likely to grow again next year, because the mycelium is not going anywhere.
Golden chanterelle (Cantharellus cibarius)
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The golden chanterelle is one of the best-known edible mushrooms in the Czech Republic and a loyal mycorrhizal partner of spruce, pine, beech and oak. Thanks to this wide range of hosts, it occurs in almost every type of forest – from the oak woods of Central Bohemia through the spruce forests of the Ore Mountains to the beech woods of the Moravian Karst. Its golden yellow fruiting bodies appear from June and, in damp weather, last until late autumn.
Research has shown that the chanterelle is particularly sensitive to air pollution – in areas with high nitrogen and sulphur deposition, its numbers fall dramatically. That is why the decline of chanterelles in the Krkonoše Mountains in the late 1980s and early 1990s was a direct indicator of the health of the local spruce forests. Their return after emissions were reduced, on the other hand, was a good sign for the whole ecosystem.
Fly agaric (Amanita muscaria)
The fly agaric is an icon of European forests and also one of the most important mycorrhizal partners of birch and spruce. Despite its toxicity, it plays an irreplaceable role in the forest ecosystem – its mycelium connects tree roots and especially helps young seedlings in their first years, when their own root system is not yet well developed. Without the fly agaric, the regeneration of birch and spruce stands after disturbances would slow down dramatically.
In the Czech Republic it grows from the lowlands up to the subalpine zone (Krkonoše, Šumava), most abundantly from August to October. Its red cap with white flakes is everywhere in films and fairy tales – and that is precisely why many people wrongly think of it as “the typical poisonous mushroom”. In reality, the fly agaric rarely causes fatal poisoning – its close relatives, the death cap and the destroying angel, are far more dangerous.
Saffron milk cap (Lactarius deliciosus)
The saffron milk cap is an exclusive mycorrhizal partner of pine – you will not find it anywhere else. It grows in pine forests on the sandy soils of Bohemia (Czech Canada, the Třeboň region, the Kokořín region) and in mountain pine woods in the Šumava. Its mycelium is so specialised that if pine disappears from a site, the milk cap does not move to another tree species – it simply vanishes from the habitat.
The saffron milk cap is a sought-after mushroom in the kitchen and also a fascinating subject for mycologists at the Czech Academy of Sciences, who study how mycorrhizal specialists respond to climate change and changes in forest management. When the fruiting body is damaged, orange milk oozes out and turns green in the air – this feature is the key to safe identification.
Mother trees (hub trees)
Researcher Suzanne Simard of the University of British Columbia showed that the largest, oldest trees in a forest – known as mother trees or hub trees – are connected to far more neighbours in the mycorrhizal network than young trees. They act as hubs of the network and, in times of drought, shade or pest attack, redistribute carbon and minerals to weaker neighbours through the mycelium.
In Czech conditions, the role of mother trees is played above all by mighty beeches in natural beech forests – for example in the Šumava National Park or in the Žofín and Boubín primeval forest reserves. That is why primeval forests and reserves with minimal human intervention are irreplaceable: their mycorrhizal networks, built up over centuries, are a fragile ecological heritage we cannot recreate artificially. The wood of old beeches and oaks has also inspired AMADEA's craftspeople – chopping and serving boards made of solid wood carry the story of every growth ring.
Common myths and misconceptions about the forest's underground network
Mycorrhizal fungi are in fact mutualists – both sides benefit. The tree gets nutrients, the fungus gets sugars. True parasites are other fungi (e.g. honey fungus), which really do weaken the tree. Confusing these two groups is one of the most common mistakes, even among experienced mushroom pickers.
The transfer of nutrients in the mycorrhizal network is neither conscious nor intentional – it follows physical and chemical gradients, much like water flowing downhill. Trees do not “communicate” in the human sense. Science does, however, confirm that the result of these processes is a real movement of resources from strong trees to weaker seedlings.
Picking or cutting fruiting bodies does not damage the mycelium – they are just the “fruit” of the underground network. What does destroy mycelium is unsuitable forest management, widespread use of pesticides and deep mechanical ploughing when preparing land for new plantings. Natural forest regeneration is therefore key to preserving mycorrhizal networks.
Overview: Mycorrhizal fungi and their trees in Czech forests
| Mushroom | Latin name | Hosts in the Czech Republic | Altitude | Edibility | Key feature |
|---|---|---|---|---|---|
| Penny bun | Boletus edulis | Spruce, beech, fir | 200–1,200 m | ✅ Excellent | White flesh that does not turn blue |
| Golden chanterelle | Cantharellus cibarius | Spruce, pine, beech, oak | 100–1,100 m | ✅ Excellent | Ridges (not gills), apricot scent |
| Fly agaric | Amanita muscaria | Birch, spruce | 200–1,400 m | ❌ Poisonous | Red cap, white flakes |
| Saffron milk cap | Lactarius deliciosus | Pine (exclusively) | 150–900 m | ✅ Good | Orange milk that turns green in the air |
| Slippery jack | Suillus luteus | Pine (exclusively) | 150–1,000 m | ✅ Good (peel the slimy cap) | Slimy cap, ring on the stem |
| Bitter bolete | Tylopilus felleus | Spruce, pine, beech | 200–1,200 m | ⚠️ Inedible (bitter) | Pinkish pores, dark network on the stem, intensely bitter |
Frequently asked questions about mycorrhiza and the internet of the forest
What is the mycorrhizal network and why is it called the internet of the forest?
The mycorrhizal network is a system of fungal threads (mycelium) that connect the roots of different trees in the soil. Minerals, carbon and chemical signals circulate through these threads – just as data travels through internet cables. The term “Wood Wide Web” was introduced by scientists in the late 1990s as a nod to the internet boom of the time.
How big can a mycorrhizal network be?
The mycelium of a single fungus can cover several hectares. In some species (e.g. the dark honey fungus, Armillaria ostoyae – which is a parasite rather than a mycorrhizal partner), individuals covering more than 900 hectares have been recorded in the USA. Mycorrhizal networks in Czech forests commonly span tens of square metres, and occasionally whole hectares.
Can the mycorrhizal network help trees weakened by the climate?
Research suggests that it can. Shaded or drought-stressed trees can receive carbon through the mycelium from neighbours in a better position. This support is limited, though – it will not save a tree that is diseased or growing in unsuitable conditions in the long term. Preserving old forests richly connected by mycorrhiza is therefore key to making forests more resilient to climate change.
Why do mushrooms grow in the same places year after year?
Because the underground mycelium survives outside the picking season. Fruiting bodies are only temporary organs for reproduction (releasing spores). The mycelium itself is permanent and can live in one place for decades – unless conditions change (felling, drought, a change in soil pH). That is why your favourite “mushroom spots” are so reliable.
Where can I find natural wooden products inspired by Czech nature?
At AMADEA you will find handmade wooden puzzles with nature motifs, candle holders made of solid wood and home decorations inspired by the forest. Everything is made from native timbers and handcrafted in the Czech Republic.
🌳 Looking for a gift made of natural wood? At AMADEA you will find handmade products from Czech forests – from decorations to kitchen accessories.
Visit AMADEAAuthor: Martin Portych – specialist in wooden products, gift advice and shop content
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